1. Forum
  2. FidoNet
  3. WEATHER

  • HVYRAIN: Excessive Rainfall Discussion

    From COD Weather Processor @1:2320/107 to All on Tue Jul 28 18:47:34 2026
    FOUS30 KWBC 281847
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    247 PM EDT Tue Jul 28 2026

    Day 1
    Valid 16Z Tue Jul 28 2026 - 12Z Wed Jul 29 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    18Z Update: An update to the Day 1 ERO has been sent to extend the
    Moderate Risk area across western MA into far southern VT. Most
    recent guidance is pointing toward a significant flash flood setup
    across that area beginning this evening and continuing through
    Wednesday morning, where training and repeating rounds of intense
    rainfall is most likely. The rest of the discussion below remains
    valid.

    Taylor

    ...Mid Atlantic and Northeast...
    A significant flash flooding day is expected across portions of the
    Mid Atlantic and Northeast. Convection is rapidly initiating
    already between 15-16Z across much of the region, and should become
    more widespread by early-mid afternoon. Growing instability in
    areas of clearing to the southeast of ongoing rain, and increasing
    PWs (likely to approach 2 inches in the Moderate Risk area by 21Z)
    should support increasingly intense rain rates by this afternoon.
    As convection becomes more widespread, there should also be larger
    clusters that develop. The combination of these factors should
    yield corridors where intense rain rates can persist in certain
    areas for 2-3 hours, and may yield locally extreme rainfall. Almost
    every available hi-res model shows at least one localized max of 5
    or more inches of rainfall in 6 hours or less. Hourly rain rates
    appear likely to exceed 2 inches in the most organized convective
    clusters, and could even reach 3 inches. Therefore, the expectation
    is for numerous cases of flash flooding associated with the high
    rain rates from this afternoon into the early evening, with the
    potential for locally significant flash flooding. Given the early
    initiation of convection, there is considerable concern for impacts
    during the evening commute in the populous urban centers of the
    Northeast corridor.

    There will be a transition in the convective pattern as we reach
    the overnight hours. A strong mid-level vort max, very evident in
    GOES East satellite channels across north-central Pennsylvania, is
    likely to induce the development of a surface low somewhere over
    the region. The position of this surface low will be critical to
    where the threat of flash flooding maximizes during the overnight
    period and as we approach 12Z (and the morning commute). Our best
    estimate is that this would be favored just southeast of the
    current trajectory of the surface low, and near the largest
    concentration of afternoon convection. For now that looks like it
    will be somewhere from SE PA to C NJ by the 00-06Z time frame, and
    lifting northeast toward S NY and CT by 06-12Z. This is where the
    latest 14Z HRRR places it, and is consistent with the ECMWF
    Ensemble and AIFS/AIFS Ensemble. However, there is still
    considerable uncertainty. The reason the position of the low is
    important is that instability should decrease while PWs stay quite
    high, favoring low-topped and very efficient convective rain bands,
    and these would tend to concentrate near and just north/east of the
    surface low in an area of maximum mesoscale forcing and low-level
    convergence. There are also signs that rain bands will extend north
    along an inverted trough, perhaps well up the Hudson Valley and
    into Vermont. While the maximum rain rates may slightly decrease
    during the overnight period, more into the 1-2 inch per hour range
    in the strongest convective bands, there would be greater potential
    for persistence, and thus locally extreme rainfall will still be
    possible -- the threat will just shift more into far southern and
    eastern New York, Long Island, Connecticut, western Massachusetts,
    and southern Vermont. It's possible there will be an ongoing rain
    band with active flash flooding around the end of the period and in
    the transition to Day 2, around the time of the Wednesday morning
    commute, particularly from Long Island north into Connecticut and
    western Massachusetts.

    ...Central and Southern Appalachians and Virginia...
    A broader Marginal Risk area was maintained from southern and
    western Maryland south into Virginia, northern North Carolina, and
    the central and southern Appalachians. A more conditional threat of
    localized heavy rainfall and flash flooding exists in these areas,
    largely due to stronger deep layer mean winds (over 30 knots),
    which should keep storm motions relatively fast. Precipitable water
    values remaining in the 1.6 inch (at higher elevations) to 2.0 inch
    (at lower elevations) range should support high instantaneous rain
    rates, which could yield localized heavy rain where any training
    could occur. However, the overall pattern does not favor widespread
    training, and thus the threat is more conditional.

    ...Four Corners States...
    The primary adjustment was to expand the Slight Risk to include
    much of northern Arizona, where probabilities of localized heavy
    rainfall have increased. The Marginal Risk was also pushed west in
    Utah to account for some signal for slow-moving thunderstorms.
    Overall, the previous reasoning still applies. The strongest signal
    for heavy rain is in northeast Colorado where precipitable water
    values are above the 90th percentile and deep layer mean wind and
    Corfidi vector magnitudes are lower (generally 10 knots or less).
    Therefore, the greatest concern would be around the time of
    convective initiation over higher terrain, and for the several
    hours afterward. With bulk shear of 30-40 knots, however, as the
    storms become more numerous they should begin to organize into
    clusters or lines and begin to establish cold pools and accelerate
    eastward onto the Plains, which would eventually reduce the threat
    of flash flooding. Further to the southwest (NM, AZ), storm motions
    should remain relatively slow and should promote the threat of
    isolated flash flooding.

    ...Western Florida Peninsula and the Keys...
    No changes. PREVIOUS DISCUSSION: A shortwave diving along the
    Florida Peninsula/Western Gulf will interact with broad diffluence
    aloft to maintain deep layer ascent for convection across the
    eastern Gulf and into parts of South Florida and the keys. Mean
    0-6km winds of just 5-10 kts will be aligned SW to NW, anti-
    parallel to collapsed Corfidi vectors, and parallel to the Keys.
    This suggests that convection will repeatedly build across the Gulf
    where PWs will be pooled at 2-2.25 inches within impressive
    2000-3000 J/kg MUCAPE leading to 2-4" of rainfall with locally
    higher amounts.

    ...Missouri Valley...
    A Marginal Risk was maintained but the Slight Risk was removed
    across this region, given a reduced signal in the hi-res ensemble
    guidance for heavy rainfall.

    Lamers/Bann


    Day 2
    Valid 12Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    ...Northeast...
    Intense rainfall, some of which will be training and repeating, is
    expected to be ongoing at the start of the Day 2 period Wednesday
    morning, particularly across western MA, far southern VT, and
    broadly across southern New England. Rainfall rates between 1-2"/hr
    at times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected. HREF neighborhood probabilities remain high (greater
    than 80 percent) for 3" totals across western/central MA into far
    southern VT. Probabilities are moderate (30-50 percent) for 5"
    totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk has been introduced for the
    day 2 period, mainly to account for what is expected to be ongoing
    in the early part of the period. The second half of the period
    (after 00Z Thu), the intensity of rainfall should subside while
    also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region north and
    eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    on Tuesday and Tuesday night. Overall, the risk area remains in
    good shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms on Wednesday. Guidance continues
    to indicate a low-probability threat for at least 3" of rain due to
    training of 1-2"/hr rain rates within favorable thermodynamics.
    This region can generally tolerate significant rain rates and this
    amount of rainfall, but any more pronounced training could result
    in isolated flash flood related impacts.

    Taylor/Bann/Weiss


    Day 3
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected, especially across the Corn Belt. The Slight Risk is in
    good shape and covers the ensemble guidance and uncertainty/spread
    among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was added.

    Taylor/Bann


    Day 4 and Day 5

    Valid 12Z Fri Jul 31 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE MID AND UPPER MISSISSIPPI, AND ON SATURDAY OVER
    PORTIONS OF THE LOWER OHIO VALLEY, TENNESSEE VALLEY, AND DEEP
    SOUTH...

    ...Mississippi Valley-Ohio Valley-Tennessee Valley-Deep South...
    On Day 4 (Friday-Friday night), minor changes were made to
    yesterday's Day 5 ERO, including refinements to the Slight Risk
    area over parts of the Mid-Upper MS Valley, based on the latest
    (00Z) global deterministic and probabilistic QPFs. The operational
    models continue to show max 24hr totals in the 3-5" range,
    particularly over IA-southeast MN-southwest WI, though again with
    some spatial spread in the guidance. 00Z Operational ECMWF has a
    bit more areal coverage of the 3+ inch totals, while the ECENS QPF
    exceedance probabilities have once again come up from the previous
    run. Based on the latest guidance, along with the most recent ECMWF
    EFI output (EFI values aoa 0.6), have nudged the southern portion
    of the Slight Risk area a little farther north across the Mid MS
    Valley.

    On Day 5 (Saturday-Saturday night), the globals continue to show a
    fairly vigorous 500 mb trough/embedded shortwave energy slowly pivoting
    into the Mid MS Valley. There isn't as strong of a signal in the
    QPF guidance compared to the previous couple of days; however, the
    amplifying upper level trough (favorable Qs forcing and increasing
    effective bulk shear) will combine with a favorable thermodynamic
    profile (ML CAPEs 1000-2000 J/Kg along a swath of 1.8-2.1" PWs) to
    generate organized heavy rainfall threat across western portions
    of the Lower OH Valley into the TN Valley and perhaps as far south
    as southern AL, depending on how far south the upper shortwave and
    favorable 0-6KM bulk shear can get. Concern within this area will
    be heavy rainfall rates (2+ in/hr) given the thermodynamic profile,
    along with the potential for cell training of convection as the
    upper shortwave begins to stall and the low-level inflow out ahead
    of it increases up and aligns more parallel to the mean 850-300 mb
    flow. Because of these factors, we felt that a Slight Risk was
    warranted.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into much of CO. The expanding mid/upper level ridge
    (600dm heights at 500 mb) will likely limit the coverage compared
    to recent days, especially on Friday.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along the New England cyclone's trailing
    front near the FL/GA border, the front that will become more
    quasi-stationary Thu-Fri before lifting lifting back north on Sat
    ahead of the approaching upper trough. Deep-layer moisture and
    instability should be more than sufficient and the guidance shows
    sufficient effective bulk shear (0-6km magnitudes generally over 20
    kts) for more organized/persistent convective organization. As a
    result, have maintained the inherited Marginal Risk on Day 4 (Fri-
    Fri night), with a similar Marginal Risk area on Day 5 (Sat-Sat
    night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7Ogph7zspibnJscm3EQYqckW9l-kycBEO6WuegSojAgQBGO-HmbelTxno9bTd4XYq51HOmqzgKNyPbTL8kJ7i1YM72Y$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7Ogph7zspibnJscm3EQYqckW9l-kycBEO6WuegSojAgQBGO-HmbelTxno9bTd4XYq51HOmqzgKNyPbTL8kJ7AZInIas$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7Ogph7zspibnJscm3EQYqckW9l-kycBEO6WuegSojAgQBGO-HmbelTxno9bTd4XYq51HOmqzgKNyPbTL8kJ73t2RkMI$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Jul 28 19:52:34 2026
    FOUS30 KWBC 281952
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    352 PM EDT Tue Jul 28 2026

    Day 1
    Valid 16Z Tue Jul 28 2026 - 12Z Wed Jul 29 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    18Z Update: An update to the Day 1 ERO has been sent to extend the
    Moderate Risk area across western MA into far southern VT. Most
    recent guidance is pointing toward a significant flash flood setup
    across that area beginning this evening and continuing through
    Wednesday morning, where training and repeating rounds of intense
    rainfall is most likely. The rest of the discussion below remains
    valid.

    Taylor

    ...Mid Atlantic and Northeast...
    A significant flash flooding day is expected across portions of the
    Mid Atlantic and Northeast. Convection is rapidly initiating
    already between 15-16Z across much of the region, and should become
    more widespread by early-mid afternoon. Growing instability in
    areas of clearing to the southeast of ongoing rain, and increasing
    PWs (likely to approach 2 inches in the Moderate Risk area by 21Z)
    should support increasingly intense rain rates by this afternoon.
    As convection becomes more widespread, there should also be larger
    clusters that develop. The combination of these factors should
    yield corridors where intense rain rates can persist in certain
    areas for 2-3 hours, and may yield locally extreme rainfall. Almost
    every available hi-res model shows at least one localized max of 5
    or more inches of rainfall in 6 hours or less. Hourly rain rates
    appear likely to exceed 2 inches in the most organized convective
    clusters, and could even reach 3 inches. Therefore, the expectation
    is for numerous cases of flash flooding associated with the high
    rain rates from this afternoon into the early evening, with the
    potential for locally significant flash flooding. Given the early
    initiation of convection, there is considerable concern for impacts
    during the evening commute in the populous urban centers of the
    Northeast corridor.

    There will be a transition in the convective pattern as we reach
    the overnight hours. A strong mid-level vort max, very evident in
    GOES East satellite channels across north-central Pennsylvania, is
    likely to induce the development of a surface low somewhere over
    the region. The position of this surface low will be critical to
    where the threat of flash flooding maximizes during the overnight
    period and as we approach 12Z (and the morning commute). Our best
    estimate is that this would be favored just southeast of the
    current trajectory of the surface low, and near the largest
    concentration of afternoon convection. For now that looks like it
    will be somewhere from SE PA to C NJ by the 00-06Z time frame, and
    lifting northeast toward S NY and CT by 06-12Z. This is where the
    latest 14Z HRRR places it, and is consistent with the ECMWF
    Ensemble and AIFS/AIFS Ensemble. However, there is still
    considerable uncertainty. The reason the position of the low is
    important is that instability should decrease while PWs stay quite
    high, favoring low-topped and very efficient convective rain bands,
    and these would tend to concentrate near and just north/east of the
    surface low in an area of maximum mesoscale forcing and low-level
    convergence. There are also signs that rain bands will extend north
    along an inverted trough, perhaps well up the Hudson Valley and
    into Vermont. While the maximum rain rates may slightly decrease
    during the overnight period, more into the 1-2 inch per hour range
    in the strongest convective bands, there would be greater potential
    for persistence, and thus locally extreme rainfall will still be
    possible -- the threat will just shift more into far southern and
    eastern New York, Long Island, Connecticut, western Massachusetts,
    and southern Vermont. It's possible there will be an ongoing rain
    band with active flash flooding around the end of the period and in
    the transition to Day 2, around the time of the Wednesday morning
    commute, particularly from Long Island north into Connecticut and
    western Massachusetts.

    ...Central and Southern Appalachians and Virginia...
    A broader Marginal Risk area was maintained from southern and
    western Maryland south into Virginia, northern North Carolina, and
    the central and southern Appalachians. A more conditional threat of
    localized heavy rainfall and flash flooding exists in these areas,
    largely due to stronger deep layer mean winds (over 30 knots),
    which should keep storm motions relatively fast. Precipitable water
    values remaining in the 1.6 inch (at higher elevations) to 2.0 inch
    (at lower elevations) range should support high instantaneous rain
    rates, which could yield localized heavy rain where any training
    could occur. However, the overall pattern does not favor widespread
    training, and thus the threat is more conditional.

    ...Four Corners States...
    The primary adjustment was to expand the Slight Risk to include
    much of northern Arizona, where probabilities of localized heavy
    rainfall have increased. The Marginal Risk was also pushed west in
    Utah to account for some signal for slow-moving thunderstorms.
    Overall, the previous reasoning still applies. The strongest signal
    for heavy rain is in northeast Colorado where precipitable water
    values are above the 90th percentile and deep layer mean wind and
    Corfidi vector magnitudes are lower (generally 10 knots or less).
    Therefore, the greatest concern would be around the time of
    convective initiation over higher terrain, and for the several
    hours afterward. With bulk shear of 30-40 knots, however, as the
    storms become more numerous they should begin to organize into
    clusters or lines and begin to establish cold pools and accelerate
    eastward onto the Plains, which would eventually reduce the threat
    of flash flooding. Further to the southwest (NM, AZ), storm motions
    should remain relatively slow and should promote the threat of
    isolated flash flooding.

    ...Western Florida Peninsula and the Keys...
    No changes. PREVIOUS DISCUSSION: A shortwave diving along the
    Florida Peninsula/Western Gulf will interact with broad diffluence
    aloft to maintain deep layer ascent for convection across the
    eastern Gulf and into parts of South Florida and the keys. Mean
    0-6km winds of just 5-10 kts will be aligned SW to NW, anti-
    parallel to collapsed Corfidi vectors, and parallel to the Keys.
    This suggests that convection will repeatedly build across the Gulf
    where PWs will be pooled at 2-2.25 inches within impressive
    2000-3000 J/kg MUCAPE leading to 2-4" of rainfall with locally
    higher amounts.

    ...Missouri Valley...
    A Marginal Risk was maintained but the Slight Risk was removed
    across this region, given a reduced signal in the hi-res ensemble
    guidance for heavy rainfall.

    Lamers/Bann


    Day 2
    Valid 12Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    ...Northeast...
    Intense rainfall, some of which will be training and repeating, is
    expected to be ongoing at the start of the Day 2 period Wednesday
    morning, particularly across western MA, far southern VT, and
    broadly across southern New England. Rainfall rates between 1-2"/hr
    at times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected. HREF neighborhood probabilities remain high (greater
    than 80 percent) for 3" totals across western/central MA into far
    southern VT. Probabilities are moderate (30-50 percent) for 5"
    totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk has been introduced for the
    day 2 period, mainly to account for what is expected to be ongoing
    in the early part of the period. The second half of the period
    (after 00Z Thu), the intensity of rainfall should subside while
    also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region north and
    eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    on Tuesday and Tuesday night. Overall, the risk area remains in
    good shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms on Wednesday. Guidance continues
    to indicate a low-probability threat for at least 3" of rain due to
    training of 1-2"/hr rain rates within favorable thermodynamics.
    This region can generally tolerate significant rain rates and this
    amount of rainfall, but any more pronounced training could result
    in isolated flash flood related impacts.

    Taylor/Bann/Weiss


    Day 3
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected, especially across the Corn Belt. The Slight Risk is in
    good shape and covers the ensemble guidance and uncertainty/spread
    among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was added.

    Taylor/Bann


    Day 4 and Day 5

    Valid 12Z Fri Jul 31 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE MID AND UPPER MISSISSIPPI, AND ON SATURDAY OVER
    PORTIONS OF THE LOWER OHIO VALLEY, TENNESSEE VALLEY, AND DEEP
    SOUTH...

    20Z Update: Previous forecast and synopsis on the upcoming pattern
    remains prevalent and consistent with regards to run-to-run
    continuity. Biggest adjustment for the D4 was a minor expansion to
    the east over southern WI and northern IL for the SLGT risk as
    ensemble mean QPF >1" saw a small shift in that direction in the
    12z NWP suite. This correlates favorably with the EC-AIFS QPF
    alignment which is even further east than what is currently
    forecast as the heaviest QPF is even east of the Mississippi around
    IA/IL. Didn't want to engage in that large of a shift, so split the
    middle and correlated the SLGT risk with the PQPF >1" probability
    that was greater than 30%, a threshold that typically favors more
    of a SLGT risk opportunity for the D4 period.

    The D5 saw an adjustment of the SLGT risk further to the N/NW over
    IL/IN as the upper level progression from our shortwave over the
    Upper Midwest will play a significant role in where there will be
    not only sufficient convective coverage, but also focusing an area
    where training/repeating cell development could play a greater role
    for flash flood prospects. There's a general consensus on the
    primary circulation aloft cutting through IL and potentially
    closing off somewhere over eastern IL down towards the western Ohio
    Valley. Some of the deterministic is pretty aggressive in their QPF presentations, mainly the models that show that earlier closed 5H
    signal. In this case, enough merit with the ensemble QPF increase
    in the region to to move the SLGT a bit further N/NW to account for
    the trend.

    There were no significant changes to the MRGL risk outlines across
    the Southeastern U.S. and the Southwestern U.S. with their
    respective patterns as the QPF forecast remains pretty consistent
    across the Central Gulf Coast into FL.

    Kleebauer

    ..Previous Discussions..

    ...Mississippi Valley-Ohio Valley-Tennessee Valley-Deep South...
    On Day 4 (Friday-Friday night), minor changes were made to
    yesterday's Day 5 ERO, including refinements to the Slight Risk
    area over parts of the Mid-Upper MS Valley, based on the latest
    (00Z) global deterministic and probabilistic QPFs. The operational
    models continue to show max 24hr totals in the 3-5" range,
    particularly over IA-southeast MN-southwest WI, though again with
    some spatial spread in the guidance. 00Z Operational ECMWF has a
    bit more areal coverage of the 3+ inch totals, while the ECENS QPF
    exceedance probabilities have once again come up from the previous
    run. Based on the latest guidance, along with the most recent ECMWF
    EFI output (EFI values aoa 0.6), have nudged the southern portion
    of the Slight Risk area a little farther north across the Mid MS
    Valley.

    On Day 5 (Saturday-Saturday night), the globals continue to show a
    fairly vigorous 500 mb trough/embedded shortwave energy slowly pivoting
    into the Mid MS Valley. There isn't as strong of a signal in the
    QPF guidance compared to the previous couple of days; however, the
    amplifying upper level trough (favorable Qs forcing and increasing
    effective bulk shear) will combine with a favorable thermodynamic
    profile (ML CAPEs 1000-2000 J/Kg along a swath of 1.8-2.1" PWs) to
    generate organized heavy rainfall threat across western portions
    of the Lower OH Valley into the TN Valley and perhaps as far south
    as southern AL, depending on how far south the upper shortwave and
    favorable 0-6KM bulk shear can get. Concern within this area will
    be heavy rainfall rates (2+ in/hr) given the thermodynamic profile,
    along with the potential for cell training of convection as the
    upper shortwave begins to stall and the low-level inflow out ahead
    of it increases up and aligns more parallel to the mean 850-300 mb
    flow. Because of these factors, we felt that a Slight Risk was
    warranted.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into much of CO. The expanding mid/upper level ridge
    (600dm heights at 500 mb) will likely limit the coverage compared
    to recent days, especially on Friday.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along the New England cyclone's trailing
    front near the FL/GA border, the front that will become more
    quasi-stationary Thu-Fri before lifting lifting back north on Sat
    ahead of the approaching upper trough. Deep-layer moisture and
    instability should be more than sufficient and the guidance shows
    sufficient effective bulk shear (0-6km magnitudes generally over 20
    kts) for more organized/persistent convective organization. As a
    result, have maintained the inherited Marginal Risk on Day 4 (Fri-
    Fri night), with a similar Marginal Risk area on Day 5 (Sat-Sat
    night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4nJDm8Wi8fKxVz1urich6haG3aQGtEqo0C7X77t84w7DULphFvxuiKOApXei6H9Z2uANSXssJMda4BqO2QRDHDKp7Po$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4nJDm8Wi8fKxVz1urich6haG3aQGtEqo0C7X77t84w7DULphFvxuiKOApXei6H9Z2uANSXssJMda4BqO2QRDD-5K2Yg$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4nJDm8Wi8fKxVz1urich6haG3aQGtEqo0C7X77t84w7DULphFvxuiKOApXei6H9Z2uANSXssJMda4BqO2QRDe9ghy0A$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Jul 29 00:41:28 2026
    FOUS30 KWBC 290041
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    841 PM EDT Tue Jul 28 2026

    Day 1
    Valid 01Z Wed Jul 29 2026 - 12Z Wed Jul 29 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    ...Mid Atlantic and Northeast...

    01Z Update: The current forecast Moderate Risk remains on track
    across the Mid Atlantic and Northeastern U.S. with heavy rainfall
    and several flash flood warnings ongoing at this hour. SLP over the
    central Mid Atlantic will continue to make headway towards the
    coast with the center of circulation likely to settle south of LI
    by the morning. Upper pattern will eventually close off over NY
    state into Northern New England, taking on a more neutral to
    negative-tilt as it evolves. This will allow for heavy rain to
    pivot over the Lower Hudson into Southern New England as flow
    becomes increasingly backed and precip likely exhibits more
    training potential in the vicinity of the Lower Hudson into western
    MA along the Berkshires. In this setup, it is likely for
    significant rainfall to occur with most deterministic inferring
    potential for >4" of additional rainfall in the hardest hit areas.
    Considering the general consistency in the hi-res CAMs, elected to
    maintain continuity with the MDT risk to ensure the setup being
    covered and to convey consistent messaging with local WFO's
    impacted.

    Kleebauer

    ..Previous Discussion..

    There will be a transition in the convective pattern as we reach
    the overnight hours. A strong mid-level vort max, very evident in
    GOES East satellite channels across north-central Pennsylvania, is
    likely to induce the development of a surface low somewhere over
    the region. The position of this surface low will be critical to
    where the threat of flash flooding maximizes during the overnight
    period and as we approach 12Z (and the morning commute). Our best
    estimate is that this would be favored just southeast of the
    current trajectory of the surface low, and near the largest
    concentration of afternoon convection. For now that looks like it
    will be somewhere from SE PA to C NJ by the 00-06Z time frame, and
    lifting northeast toward S NY and CT by 06-12Z. This is where the
    latest 14Z HRRR places it, and is consistent with the ECMWF
    Ensemble and AIFS/AIFS Ensemble. However, there is still
    considerable uncertainty. The reason the position of the low is
    important is that instability should decrease while PWs stay quite
    high, favoring low-topped and very efficient convective rain bands,
    and these would tend to concentrate near and just north/east of the
    surface low in an area of maximum mesoscale forcing and low-level
    convergence. There are also signs that rain bands will extend north
    along an inverted trough, perhaps well up the Hudson Valley and
    into Vermont. While the maximum rain rates may slightly decrease
    during the overnight period, more into the 1-2 inch per hour range
    in the strongest convective bands, there would be greater potential
    for persistence, and thus locally extreme rainfall will still be
    possible -- the threat will just shift more into far southern and
    eastern New York, Long Island, Connecticut, western Massachusetts,
    and southern Vermont. It's possible there will be an ongoing rain
    band with active flash flooding around the end of the period and in
    the transition to Day 2, around the time of the Wednesday morning
    commute, particularly from Long Island north into Connecticut and
    western Massachusetts.

    Taylor

    ...Central and Southern Appalachians and Virginia...

    01Z Update: Removed a large portion of Southwest VA from the MRGL
    as rainfall threat over the region remains unlikely, or is subject
    to little offering for flash flooding. Quick-moving vort max at the
    base of the mean trough continues to press southeast out of the
    Tennessee Valley. A line of thunderstorms is likely to maintain
    headway into SC/GA through the first part of the evening before
    dissipating allowing a maintenance of the MRGL risk across the
    Southern Appalachians. A few hours exist for heavy rainfall across
    the Southern Delmarva into the VA Tidewater, but threat should
    dwindle after 04z across the entire area. Fast cell motions should
    limit the extent of any flash flood risks, but some of the more
    complex terrain in the Southern Appalachians could see an isolated
    instance of flooding considering rates between 1-2"/hr prevalent in
    the cells moving over the area.

    ...Four Corners States...

    01Z Update: Scattered bouts of heavy rain will continue for at
    least the next 3-6 hours across the Southwest with the heaviest
    rainfall concentrating over the Front Range of CO thanks to the
    influence from a stronger mid-level shortwave ejecting out of the
    Rockies. Several flash flood warnings remain in effect in the
    terrain from CO into NM and AZ. Models indicate local pockets of up
    to 1" across portions of AZ and NM, but upwards of 2-3" possible
    over the Front Range of CO up into southwestern NE. The previous
    SLGT risk was generally maintained, but extended a bit further
    north into NE to account for current heavy convection in the area.
    Also trimmed out portions of AZ (Central Mogollon Rim) as rainfall
    chances in the area are have likely subsided for the rest of the
    period with only an isolated cell or two plausible to the northwest
    of Flagstaff.

    Kleebauer


    Day 2
    Valid 12Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    ...Northeast...
    Intense rainfall, some of which will be training and repeating, is
    expected to be ongoing at the start of the Day 2 period Wednesday
    morning, particularly across western MA, far southern VT, and
    broadly across southern New England. Rainfall rates between 1-2"/hr
    at times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected. HREF neighborhood probabilities remain high (greater
    than 80 percent) for 3" totals across western/central MA into far
    southern VT. Probabilities are moderate (30-50 percent) for 5"
    totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk has been introduced for the
    day 2 period, mainly to account for what is expected to be ongoing
    in the early part of the period. The second half of the period
    (after 00Z Thu), the intensity of rainfall should subside while
    also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region north and
    eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    on Tuesday and Tuesday night. Overall, the risk area remains in
    good shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms on Wednesday. Guidance continues
    to indicate a low-probability threat for at least 3" of rain due to
    training of 1-2"/hr rain rates within favorable thermodynamics.
    This region can generally tolerate significant rain rates and this
    amount of rainfall, but any more pronounced training could result
    in isolated flash flood related impacts.

    Taylor/Bann/Weiss


    Day 3
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected, especially across the Corn Belt. The Slight Risk is in
    good shape and covers the ensemble guidance and uncertainty/spread
    among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was added.

    Taylor/Bann


    Day 4 and Day 5

    Valid 12Z Fri Jul 31 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE MID AND UPPER MISSISSIPPI, AND ON SATURDAY OVER
    PORTIONS OF THE LOWER OHIO VALLEY, TENNESSEE VALLEY, AND DEEP
    SOUTH...

    20Z Update: Previous forecast and synopsis on the upcoming pattern
    remains prevalent and consistent with regards to run-to-run
    continuity. Biggest adjustment for the D4 was a minor expansion to
    the east over southern WI and northern IL for the SLGT risk as
    ensemble mean QPF >1" saw a small shift in that direction in the
    12z NWP suite. This correlates favorably with the EC-AIFS QPF
    alignment which is even further east than what is currently
    forecast as the heaviest QPF is even east of the Mississippi around
    IA/IL. Didn't want to engage in that large of a shift, so split the
    middle and correlated the SLGT risk with the PQPF >1" probability
    that was greater than 30%, a threshold that typically favors more
    of a SLGT risk opportunity for the D4 period.

    The D5 saw an adjustment of the SLGT risk further to the N/NW over
    IL/IN as the upper level progression from our shortwave over the
    Upper Midwest will play a significant role in where there will be
    not only sufficient convective coverage, but also focusing an area
    where training/repeating cell development could play a greater role
    for flash flood prospects. There's a general consensus on the
    primary circulation aloft cutting through IL and potentially
    closing off somewhere over eastern IL down towards the western Ohio
    Valley. Some of the deterministic is pretty aggressive in their QPF presentations, mainly the models that show that earlier closed 5H
    signal. In this case, enough merit with the ensemble QPF increase
    in the region to to move the SLGT a bit further N/NW to account for
    the trend.

    There were no significant changes to the MRGL risk outlines across
    the Southeastern U.S. and the Southwestern U.S. with their
    respective patterns as the QPF forecast remains pretty consistent
    across the Central Gulf Coast into FL.

    ..Previous Discussions..

    ...Mississippi Valley-Ohio Valley-Tennessee Valley-Deep South...
    On Day 4 (Friday-Friday night), minor changes were made to
    yesterday's Day 5 ERO, including refinements to the Slight Risk
    area over parts of the Mid-Upper MS Valley, based on the latest
    (00Z) global deterministic and probabilistic QPFs. The operational
    models continue to show max 24hr totals in the 3-5" range,
    particularly over IA-southeast MN-southwest WI, though again with
    some spatial spread in the guidance. 00Z Operational ECMWF has a
    bit more areal coverage of the 3+ inch totals, while the ECENS QPF
    exceedance probabilities have once again come up from the previous
    run. Based on the latest guidance, along with the most recent ECMWF
    EFI output (EFI values aoa 0.6), have nudged the southern portion
    of the Slight Risk area a little farther north across the Mid MS
    Valley.

    On Day 5 (Saturday-Saturday night), the globals continue to show a
    fairly vigorous 500 mb trough/embedded shortwave energy slowly pivoting
    into the Mid MS Valley. There isn't as strong of a signal in the
    QPF guidance compared to the previous couple of days; however, the
    amplifying upper level trough (favorable Qs forcing and increasing
    effective bulk shear) will combine with a favorable thermodynamic
    profile (ML CAPEs 1000-2000 J/Kg along a swath of 1.8-2.1" PWs) to
    generate organized heavy rainfall threat across western portions
    of the Lower OH Valley into the TN Valley and perhaps as far south
    as southern AL, depending on how far south the upper shortwave and
    favorable 0-6KM bulk shear can get. Concern within this area will
    be heavy rainfall rates (2+ in/hr) given the thermodynamic profile,
    along with the potential for cell training of convection as the
    upper shortwave begins to stall and the low-level inflow out ahead
    of it increases up and aligns more parallel to the mean 850-300 mb
    flow. Because of these factors, we felt that a Slight Risk was
    warranted.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into much of CO. The expanding mid/upper level ridge
    (600dm heights at 500 mb) will likely limit the coverage compared
    to recent days, especially on Friday.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along the New England cyclone's trailing
    front near the FL/GA border, the front that will become more
    quasi-stationary Thu-Fri before lifting lifting back north on Sat
    ahead of the approaching upper trough. Deep-layer moisture and
    instability should be more than sufficient and the guidance shows
    sufficient effective bulk shear (0-6km magnitudes generally over 20
    kts) for more organized/persistent convective organization. As a
    result, have maintained the inherited Marginal Risk on Day 4 (Fri-
    Fri night), with a similar Marginal Risk area on Day 5 (Sat-Sat
    night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!668kvj-pgVZ0J76C58mbF0JXms3blfC_nomO8zUYoEbcoLoNNdoOuD86Ukzw6VyE1_lj_RwXxeWgZD1gi944ox_Ej6A$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!668kvj-pgVZ0J76C58mbF0JXms3blfC_nomO8zUYoEbcoLoNNdoOuD86Ukzw6VyE1_lj_RwXxeWgZD1gi9448jbePos$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!668kvj-pgVZ0J76C58mbF0JXms3blfC_nomO8zUYoEbcoLoNNdoOuD86Ukzw6VyE1_lj_RwXxeWgZD1gi944vGbIfSE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Jul 29 08:14:44 2026
    FOUS30 KWBC 290814
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    414 AM EDT Wed Jul 29 2026

    Day 1
    Valid 12Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    ...Northeast...
    Intense rainfall will be on-going over portions of the Northeast as
    the Day 1 period begins at 29/12Z, with some training of cells and
    some places experiencing multiple rounds of heavy rainfall--particularly
    across western Massachusetts, far southern Vermont, and broadly
    across southern New England. Rainfall rates between 1-2"/hr at
    times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected.

    HREF/RRFS neighborhood probabilities from the 29/00Z runs remained
    high (greater than 80 percent) for 3" totals across
    western/central MA into far southern VT. Probabilities are moderate
    (30-50 percent) for 5" totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk was maintained with few
    changes given the cumulative rainfall amounts. After 30/00Z...the
    intensity of rainfall should subside while also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region northward and eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    prior to the start of the Day 1 period at 29/12Z. Persistence in
    the pattern and moisture distribution leaves the risk area in good
    shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms today into tonight. Guidance
    continues to indicate a low-probability threat for at least 3" of
    rain due to training of 1-2"/hr rain rates within favorable
    thermodynamics. This region can generally tolerate significant rain
    rates and this amount of rainfall, but any more pronounced
    training could result in isolated flash flood related impacts.

    Taylor/Bann


    Day 2
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected given the potential for training and repeat-convection. The
    Slight Risk remained in good shape and only minor adjustments were
    needed to covers the 29/00Z ensemble guidance and to account for
    the uncertainty/spread among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia near the state line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was maintained.

    Taylor/Bann


    Day 3
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms on Friday morning. The flow pattern on the northern
    part of the upper high anchored to its west sharpens during the
    day...which induces a turn to the south for the northern Plains
    system. Tended to follow the numerical guidance for placement of
    the Marginal and Slight risk areas where the synoptic scale forcing
    is greatest. This necessitated a bit more eastward nudging from
    the previous outlook. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance. Both the GFS and ECMWF placed their axis of highest precipitable water (1.8 to 2.2 inches) near the Mississippi River
    early in the period which gets deflected towards the Tennessee
    Valley by early Saturday morning.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall is possible in proximity to an
    east-west oriented quasi-stationary front that had been associated
    with a Northeast US cyclone in previous days. Deep-layer moisture
    and instability should be more than sufficient and the guidance
    shows sufficient effective bulk shear (0-6km magnitudes generally
    over 20 kts) for more organized/persistent convective organization.
    As a result, maintained the inherited Marginal Risk .

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 4 and Day 5

    Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL SATURDAY OVER
    PORTIONS OF THE OHIO VALLEY AND CUMBERLAND PLATEAU...

    ...Ohio and Tennessee Valleys into parts of the Southeast...
    On Day 4 (Sat-Sat night), rather significant changes were made to
    yesterday's Day 5 ERO, based on the latest guidance trends.
    Specifically, the globals and most ensembles show the upper trough
    amplifying somewhat with the influx of shortwave
    energy/convectively- aided vort lobes dropping southeast. However,
    most of the guidance show less amplification compared to last
    night's runs, with more of a positive to neutral tilt to the trough
    vs. negative. This in turn is allowing for a more progressive
    west-to-east shift in the pre- frontal rainfall east of the
    Mississippi, supported (perhaps led by) both the GFS and ECMWF AI
    models. Therefore the Marginal Risk and encompassing Slight Risk
    areas were shifted east as well, with the Slight Risk confined to
    mainly the northern areas (OH Valley into Cumberland Plateau) per
    the ECMWF and GFS AI trends, along with the highest 24hr QPF
    exceedance probabilities per the 00Z ECENS, and where there is a
    signal (albeit weak) per the most recent ECMWF EFI. The Slight Risk
    is also in an area with comparatively lower 1/3/6 hr FFG vs. areas
    farther south.

    ...Interior Northeast...
    Aforementioned longwave 500 mb trough does begin to take on a more
    neutral to negative tilt on Day 5 (Sun-Sun night) per both the GFS
    and ECMWF. As this occurs, the eastward progression of the
    favorable pre-trough/front dynamical forcing and associated
    moisture axis (PWs of 1.75-2.00") will begin to slow considerably,
    thereby allowing for multiple rounds of moderate-heavy rainfall.
    For now, have hoisted a Marginal Risk across this region on Day 5,
    as the maximum 24hr deterministic QPFs from the latest global runs
    are still (for the time being) under 3".

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into south-central CO on Day 4. By Day 5 (Sun-Sun
    night), both the deterministic and probabilistic QPFs per the
    global and AI guidance would support a smaller MGNL Risk area.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization. As a result, have maintained the inherited Marginal
    Risk on Day 4 (Sat-Sat night), with a similar Marginal Risk area
    on Day 5 (Sun-Sun night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7-YlZcXfln0BcazGW3TZRmCzwl2C4nDpB0O4ZalKer9xamtI0trZBJUkuZQE9nOXfZeI-_V6A-puuu3pLraNV4z1EjY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7-YlZcXfln0BcazGW3TZRmCzwl2C4nDpB0O4ZalKer9xamtI0trZBJUkuZQE9nOXfZeI-_V6A-puuu3pLraNFZdLYMc$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7-YlZcXfln0BcazGW3TZRmCzwl2C4nDpB0O4ZalKer9xamtI0trZBJUkuZQE9nOXfZeI-_V6A-puuu3pLraNFKWG5wA$

    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Jul 29 11:38:08 2026
    FOUS30 KWBC 291137
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    737 AM EDT Wed Jul 29 2026

    Day 1
    Valid 12Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE NORTHEAST...

    11z Update: We expanded the MDT risk westward into eastern NY given observational and model trends. A stationary convergence axis is
    focusing a band of intense rainfall over far eastern NY...a bit
    west of earlier forecasts. Not much instability along this axis,
    but strong convergence is overcoming this and supporting low
    topped convection with efficient warm rain processes. As the low
    over Long Island moves northward expect the rainfall axis to pivot
    and persist over eastern NY, and portions of far western CT/MA.
    Areas of significant flash flooding are likely through the
    morning, with high end life-threatneing impacts possible across the
    mid to upper Hudson Valley and point just east towards the CT/MA
    border.

    Chenard

    ...Previous Discussion...

    ...Northeast...
    Intense rainfall will be on-going over portions of the Northeast as
    the Day 1 period begins at 29/12Z, with some training of cells and
    some places experiencing multiple rounds of heavy rainfall--particularly
    across western Massachusetts, far southern Vermont, and broadly
    across southern New England. Rainfall rates between 1-2"/hr at
    times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected.

    HREF/RRFS neighborhood probabilities from the 29/00Z runs remained
    high (greater than 80 percent) for 3" totals across
    western/central MA into far southern VT. Probabilities are moderate
    (30-50 percent) for 5" totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk was maintained with few
    changes given the cumulative rainfall amounts. After 30/00Z...the
    intensity of rainfall should subside while also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region northward and eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    prior to the start of the Day 1 period at 29/12Z. Persistence in
    the pattern and moisture distribution leaves the risk area in good
    shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms today into tonight. Guidance
    continues to indicate a low-probability threat for at least 3" of
    rain due to training of 1-2"/hr rain rates within favorable
    thermodynamics. This region can generally tolerate significant rain
    rates and this amount of rainfall, but any more pronounced
    training could result in isolated flash flood related impacts.

    Taylor/Bann


    Day 2
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected given the potential for training and repeat-convection. The
    Slight Risk remained in good shape and only minor adjustments were
    needed to covers the 29/00Z ensemble guidance and to account for
    the uncertainty/spread among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia near the state line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was maintained.

    Taylor/Bann


    Day 3
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms on Friday morning. The flow pattern on the northern
    part of the upper high anchored to its west sharpens during the
    day...which induces a turn to the south for the northern Plains
    system. Tended to follow the numerical guidance for placement of
    the Marginal and Slight risk areas where the synoptic scale forcing
    is greatest. This necessitated a bit more eastward nudging from
    the previous outlook. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance. Both the GFS and ECMWF placed their axis of highest precipitable water (1.8 to 2.2 inches) near the Mississippi River
    early in the period which gets deflected towards the Tennessee
    Valley by early Saturday morning.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall is possible in proximity to an
    east-west oriented quasi-stationary front that had been associated
    with a Northeast US cyclone in previous days. Deep-layer moisture
    and instability should be more than sufficient and the guidance
    shows sufficient effective bulk shear (0-6km magnitudes generally
    over 20 kts) for more organized/persistent convective organization.
    As a result, maintained the inherited Marginal Risk .

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 4 and Day 5

    Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL SATURDAY OVER
    PORTIONS OF THE OHIO VALLEY AND CUMBERLAND PLATEAU...

    ...Ohio and Tennessee Valleys into parts of the Southeast...
    On Day 4 (Sat-Sat night), rather significant changes were made to
    yesterday's Day 5 ERO, based on the latest guidance trends.
    Specifically, the globals and most ensembles show the upper trough
    amplifying somewhat with the influx of shortwave
    energy/convectively- aided vort lobes dropping southeast. However,
    most of the guidance show less amplification compared to last
    night's runs, with more of a positive to neutral tilt to the trough
    vs. negative. This in turn is allowing for a more progressive
    west-to-east shift in the pre- frontal rainfall east of the
    Mississippi, supported (perhaps led by) both the GFS and ECMWF AI
    models. Therefore the Marginal Risk and encompassing Slight Risk
    areas were shifted east as well, with the Slight Risk confined to
    mainly the northern areas (OH Valley into Cumberland Plateau) per
    the ECMWF and GFS AI trends, along with the highest 24hr QPF
    exceedance probabilities per the 00Z ECENS, and where there is a
    signal (albeit weak) per the most recent ECMWF EFI. The Slight Risk
    is also in an area with comparatively lower 1/3/6 hr FFG vs. areas
    farther south.

    ...Interior Northeast...
    Aforementioned longwave 500 mb trough does begin to take on a more
    neutral to negative tilt on Day 5 (Sun-Sun night) per both the GFS
    and ECMWF. As this occurs, the eastward progression of the
    favorable pre-trough/front dynamical forcing and associated
    moisture axis (PWs of 1.75-2.00") will begin to slow considerably,
    thereby allowing for multiple rounds of moderate-heavy rainfall.
    For now, have hoisted a Marginal Risk across this region on Day 5,
    as the maximum 24hr deterministic QPFs from the latest global runs
    are still (for the time being) under 3".

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into south-central CO on Day 4. By Day 5 (Sun-Sun
    night), both the deterministic and probabilistic QPFs per the
    global and AI guidance would support a smaller MGNL Risk area.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization. As a result, have maintained the inherited Marginal
    Risk on Day 4 (Sat-Sat night), with a similar Marginal Risk area
    on Day 5 (Sun-Sun night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!-UnuoLs-Y9uDUbhauP-ciyDsGIyovwEqKju7mTbKiBMwFG_432eX-IKYabiZqgnoGCi7_xRj8OhReTCTqC26xS-L59U$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!-UnuoLs-Y9uDUbhauP-ciyDsGIyovwEqKju7mTbKiBMwFG_432eX-IKYabiZqgnoGCi7_xRj8OhReTCTqC26yeFPhtk$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!-UnuoLs-Y9uDUbhauP-ciyDsGIyovwEqKju7mTbKiBMwFG_432eX-IKYabiZqgnoGCi7_xRj8OhReTCTqC26Od_IDPQ$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Jul 29 15:48:34 2026
    FOUS30 KWBC 291548
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1148 AM EDT Wed Jul 29 2026

    Day 1
    Valid 16Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR THE
    BERKSHIRES AND SURROUNDING AREAS...

    ...16Z Update...

    The Moderate Risk was trimmed from the east across central
    Massachusetts and eastern Connecticut with this update. While rain
    is ongoing in most of these areas, the area didn't see anywhere
    near as much rain as areas further west from the Berkshires to the
    Hudson Valley, so the area remains in a Slight.

    The Marginal and Slight risk areas were trimmed on the southern end
    along Long Island Sound (including NYC), as the steadiest rains in
    that area have ended. Scattered showers can't be ruled out, but
    even in urban areas should not produce enough rain to cause even
    isolated flash flooding.

    Minor tweaks were made to other portions of the Northeast.

    Out west, the Marginal Risk was extended northwest to include the
    Missouri River valley in eastern Nebraska and Kansas, as well as
    western Iowa and Missouri, including the KC Metro. This is
    primarily for heavy but slow moving storms that have developed in
    this area from an overnight MCS.

    Finally, the Slight Risk in Colorado was expanded south to include
    the extreme northeastern fringe of New Mexico, where afternoon
    showers and thunderstorms that will be at least initially tied to
    the terrain may cause widely scattered instances of flash flooding.

    Wegman

    ...Previous Discussion...

    ...Northeast...
    Intense rainfall will be on-going over portions of the Northeast as
    the Day 1 period begins at 29/12Z, with some training of cells and
    some places experiencing multiple rounds of heavy rainfall--particularly
    across western Massachusetts, far southern Vermont, and broadly
    across southern New England. Rainfall rates between 1-2"/hr at
    times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected.

    HREF/RRFS neighborhood probabilities from the 29/00Z runs remained
    high (greater than 80 percent) for 3" totals across
    western/central MA into far southern VT. Probabilities are moderate
    (30-50 percent) for 5" totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk was maintained with few
    changes given the cumulative rainfall amounts. After 30/00Z...the
    intensity of rainfall should subside while also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region northward and eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    prior to the start of the Day 1 period at 29/12Z. Persistence in
    the pattern and moisture distribution leaves the risk area in good
    shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms today into tonight. Guidance
    continues to indicate a low-probability threat for at least 3" of
    rain due to training of 1-2"/hr rain rates within favorable
    thermodynamics. This region can generally tolerate significant rain
    rates and this amount of rainfall, but any more pronounced
    training could result in isolated flash flood related impacts.

    Taylor/Bann


    Day 2
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEY...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected given the potential for training and repeat-convection. The
    Slight Risk remained in good shape and only minor adjustments were
    needed to covers the 29/00Z ensemble guidance and to account for
    the uncertainty/spread among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia near the state line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was maintained.

    Taylor/Bann


    Day 3
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms on Friday morning. The flow pattern on the northern
    part of the upper high anchored to its west sharpens during the
    day...which induces a turn to the south for the northern Plains
    system. Tended to follow the numerical guidance for placement of
    the Marginal and Slight risk areas where the synoptic scale forcing
    is greatest. This necessitated a bit more eastward nudging from
    the previous outlook. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance. Both the GFS and ECMWF placed their axis of highest precipitable water (1.8 to 2.2 inches) near the Mississippi River
    early in the period which gets deflected towards the Tennessee
    Valley by early Saturday morning.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall is possible in proximity to an
    east-west oriented quasi-stationary front that had been associated
    with a Northeast US cyclone in previous days. Deep-layer moisture
    and instability should be more than sufficient and the guidance
    shows sufficient effective bulk shear (0-6km magnitudes generally
    over 20 kts) for more organized/persistent convective organization.
    As a result, maintained the inherited Marginal Risk .

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 4 and Day 5

    Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL SATURDAY OVER
    PORTIONS OF THE OHIO VALLEY AND CUMBERLAND PLATEAU...

    ...Ohio and Tennessee Valleys into parts of the Southeast...
    On Day 4 (Sat-Sat night), rather significant changes were made to
    yesterday's Day 5 ERO, based on the latest guidance trends.
    Specifically, the globals and most ensembles show the upper trough
    amplifying somewhat with the influx of shortwave
    energy/convectively- aided vort lobes dropping southeast. However,
    most of the guidance show less amplification compared to last
    night's runs, with more of a positive to neutral tilt to the trough
    vs. negative. This in turn is allowing for a more progressive
    west-to-east shift in the pre- frontal rainfall east of the
    Mississippi, supported (perhaps led by) both the GFS and ECMWF AI
    models. Therefore the Marginal Risk and encompassing Slight Risk
    areas were shifted east as well, with the Slight Risk confined to
    mainly the northern areas (OH Valley into Cumberland Plateau) per
    the ECMWF and GFS AI trends, along with the highest 24hr QPF
    exceedance probabilities per the 00Z ECENS, and where there is a
    signal (albeit weak) per the most recent ECMWF EFI. The Slight Risk
    is also in an area with comparatively lower 1/3/6 hr FFG vs. areas
    farther south.

    ...Interior Northeast...
    Aforementioned longwave 500 mb trough does begin to take on a more
    neutral to negative tilt on Day 5 (Sun-Sun night) per both the GFS
    and ECMWF. As this occurs, the eastward progression of the
    favorable pre-trough/front dynamical forcing and associated
    moisture axis (PWs of 1.75-2.00") will begin to slow considerably,
    thereby allowing for multiple rounds of moderate-heavy rainfall.
    For now, have hoisted a Marginal Risk across this region on Day 5,
    as the maximum 24hr deterministic QPFs from the latest global runs
    are still (for the time being) under 3".

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into south-central CO on Day 4. By Day 5 (Sun-Sun
    night), both the deterministic and probabilistic QPFs per the
    global and AI guidance would support a smaller MGNL Risk area.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization. As a result, have maintained the inherited Marginal
    Risk on Day 4 (Sat-Sat night), with a similar Marginal Risk area
    on Day 5 (Sun-Sun night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6ShoRa0MIGBtX7ltNAtdlp2vVHfdFTcFuje5WZWGs7GxN3ylziLJQJIW_gMMDxUT5R8nrWlGJp4fb0E-rsQABsDmXAY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6ShoRa0MIGBtX7ltNAtdlp2vVHfdFTcFuje5WZWGs7GxN3ylziLJQJIW_gMMDxUT5R8nrWlGJp4fb0E-rsQAr2QW7rQ$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6ShoRa0MIGBtX7ltNAtdlp2vVHfdFTcFuje5WZWGs7GxN3ylziLJQJIW_gMMDxUT5R8nrWlGJp4fb0E-rsQAgp-zvCg$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Jul 30 02:20:40 2026
    FOUS30 KWBC 300103
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    903 PM EDT Wed Jul 29 2026

    Day 1
    Valid 01Z Thu Jul 30 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF NEW
    ENGLAND, UPSTATE NEW YORK, AND CENTRAL TO EASTERN COLORADO...

    01Z Update...

    ...Northeast...
    The Moderate Risk centered over the Hudson Valley
    into the Berkshire and southern Green mountains was removed with
    this update. Drier air wrapping into the low that brought very
    heavy rains to the region has brought a much-needed pause this
    evening to the areas most severely impacted. While deeper moisture
    wrapping back into the area from the east may bring some additional
    showers and some isolated heavy amounts, widespread additional
    heavy amounts within the previous Moderate Risk area are not
    expected. However, given the antecedent conditions and the
    potential for isolated heavier amounts that would easily exceed
    current FFGs, a Slight Risk was maintained. Both the HREF and REFS
    indicate the greater threat for heavier amounts (2+ inches) will
    center farther east from southern coastal Maine, New Hampshire, and northeastern Massachusetts across southern New Hampshire, where
    20-30kt low level onshore flow will continue to support a moisture-
    rich environment into the overnight.

    Elsewhere, smaller adjustments were made based on current
    observation trends and short-term guidance.

    Pereira

    Previous Discussion...

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region northward and eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    prior to the start of the Day 1 period at 29/12Z. Persistence in
    the pattern and moisture distribution leaves the risk area in good
    shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms today into tonight. Guidance
    continues to indicate a low-probability threat for at least 3" of
    rain due to training of 1-2"/hr rain rates within favorable
    thermodynamics. This region can generally tolerate significant rain
    rates and this amount of rainfall, but any more pronounced
    training could result in isolated flash flood related impacts.

    Taylor/Bann


    Day 2
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    ...2030Z Update...

    No major changes were needed with this afternoon's update. The
    Slight Risk over the Plains and Midwest was expanded westward with
    the latest update due to guidance moving the area of heaviest
    rainfall westward as compared to prior forecasts. Otherwise, few
    changes were needed. The heaviest rains through the period continue
    to be forecast from northeastern Nebraska through southwestern
    Minnesota.

    Storm coverage and intensity across the 4 Corners region appears
    significantly muted as compared with previous days. The Marginal
    Risk in the area was trimmed back to portions of Arizona and New
    Mexico as a result.

    A moisture feed from the Gulf will allow for a few storms to form
    over western Arkansas and into the Lower Mississippi Valley. The
    Marginal Risks were combined along the front.

    Lingering moisture along the New England coast could continue to
    pose an isolated flash flooding threat, so the Marginal was
    maintained and expanded a bit over southeastern Massachusetts,
    Rhode Island, and eastern Connecticut.

    Wegman

    ...Previous Discussion...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected given the potential for training and repeat-convection. The
    Slight Risk remained in good shape and only minor adjustments were
    needed to covers the 29/00Z ensemble guidance and to account for
    the uncertainty/spread among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia near the state line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was maintained.

    Taylor/Bann


    Day 3
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...2030Z Update...

    A small increase in coverage of heavy rain across the Mid-
    Mississippi Valley led to a small expansion of the Slight to cover
    portions of eastern Missouri and western Kentucky with this update.
    The heaviest rains continue to be focused into far eastern Iowa,
    northwestern Illinois and southwestern Wisconsin, where no changes
    were made as the forecast remains on track.

    Elsewhere, some small adjustments of the MRGL to remove portions of northwestern New Mexico and include more of the Texas Panhandle
    were made, but total coverage and intensity of storms in these
    areas remains little changed.

    Wegman

    ...Previous Discussion...

    Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms on Friday morning. The flow pattern on the northern
    part of the upper high anchored to its west sharpens during the
    day...which induces a turn to the south for the northern Plains
    system. Tended to follow the numerical guidance for placement of
    the Marginal and Slight risk areas where the synoptic scale forcing
    is greatest. This necessitated a bit more eastward nudging from
    the previous outlook. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance. Both the GFS and ECMWF placed their axis of highest precipitable water (1.8 to 2.2 inches) near the Mississippi River
    early in the period which gets deflected towards the Tennessee
    Valley by early Saturday morning.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall is possible in proximity to an
    east-west oriented quasi-stationary front that had been associated
    with a Northeast US cyclone in previous days. Deep-layer moisture
    and instability should be more than sufficient and the guidance
    shows sufficient effective bulk shear (0-6km magnitudes generally
    over 20 kts) for more organized/persistent convective organization.
    As a result, maintained the inherited Marginal Risk .

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 4 and Day 5

    Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL SATURDAY OVER
    PORTIONS OF THE OHIO AND TENNESSEE VALLEYS...

    2030Z Update...
    Extended the Day 4 Slight Risk farther south from the Ohio into the
    Tennessee Valley. Storms are expected to develop ahead of the cold
    front associated with the shortwave trough moving through the
    Midwest on Saturday. The model spread with regards to where the
    better forcing will focus and its potential impact on the
    development of heavier amounts is notable. However, the 12Z
    guidance presented enough of a signal to warrant extending the
    Slight Risk farther south. Storms that develop in this area will
    have access to deeper moisture (PWs ~2-2.25 inches) and likely
    greater instability, supporting heavy rates.

    Elsewhere, made only minor adjustments to outlook areas on both
    days.

    Pereira

    ...Ohio and Tennessee Valleys into parts of the Southeast...
    On Day 4 (Sat-Sat night), rather significant changes were made to
    yesterday's Day 5 ERO, based on the latest guidance trends.
    Specifically, the globals and most ensembles show the upper trough
    amplifying somewhat with the influx of shortwave
    energy/convectively- aided vort lobes dropping southeast. However,
    most of the guidance show less amplification compared to last
    night's runs, with more of a positive to neutral tilt to the trough
    vs. negative. This in turn is allowing for a more progressive
    west-to-east shift in the pre- frontal rainfall east of the
    Mississippi, supported (perhaps led by) both the GFS and ECMWF AI
    models. Therefore the Marginal Risk and encompassing Slight Risk
    areas were shifted east as well, with the Slight Risk confined to
    mainly the northern areas (OH Valley into Cumberland Plateau) per
    the ECMWF and GFS AI trends, along with the highest 24hr QPF
    exceedance probabilities per the 00Z ECENS, and where there is a
    signal (albeit weak) per the most recent ECMWF EFI. The Slight Risk
    is also in an area with comparatively lower 1/3/6 hr FFG vs. areas
    farther south.

    ...Interior Northeast...
    Aforementioned longwave 500 mb trough does begin to take on a more
    neutral to negative tilt on Day 5 (Sun-Sun night) per both the GFS
    and ECMWF. As this occurs, the eastward progression of the
    favorable pre-trough/front dynamical forcing and associated
    moisture axis (PWs of 1.75-2.00") will begin to slow considerably,
    thereby allowing for multiple rounds of moderate-heavy rainfall.
    For now, have hoisted a Marginal Risk across this region on Day 5,
    as the maximum 24hr deterministic QPFs from the latest global runs
    are still (for the time being) under 3".

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into south-central CO on Day 4. By Day 5 (Sun-Sun
    night), both the deterministic and probabilistic QPFs per the
    global and AI guidance would support a smaller MGNL Risk area.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization. As a result, have maintained the inherited Marginal
    Risk on Day 4 (Sat-Sat night), with a similar Marginal Risk area
    on Day 5 (Sun-Sun night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!9oiXoU2qVjt5mRl76H4EvtuYPdJ4J_nlXC-ZWzZncfcYGDKiUpplaqO3SfUqrNp_Zbc0o9BZGX1e8_1CrBiF9MdEAis$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!9oiXoU2qVjt5mRl76H4EvtuYPdJ4J_nlXC-ZWzZncfcYGDKiUpplaqO3SfUqrNp_Zbc0o9BZGX1e8_1CrBiFAwREsug$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!9oiXoU2qVjt5mRl76H4EvtuYPdJ4J_nlXC-ZWzZncfcYGDKiUpplaqO3SfUqrNp_Zbc0o9BZGX1e8_1CrBiFpbdwcLk$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Jul 30 02:31:20 2026
    FOUS30 KWBC 292001
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    401 PM EDT Wed Jul 29 2026

    Day 1
    Valid 16Z Wed Jul 29 2026 - 12Z Thu Jul 30 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR THE
    BERKSHIRES AND SURROUNDING AREAS...

    ...16Z Update...

    The Moderate Risk was trimmed from the east across central
    Massachusetts and eastern Connecticut with this update. While rain
    is ongoing in most of these areas, the area didn't see anywhere
    near as much rain as areas further west from the Berkshires to the
    Hudson Valley, so the area remains in a Slight.

    The Marginal and Slight risk areas were trimmed on the southern end
    along Long Island Sound (including NYC), as the steadiest rains in
    that area have ended. Scattered showers can't be ruled out, but
    even in urban areas should not produce enough rain to cause even
    isolated flash flooding.

    Minor tweaks were made to other portions of the Northeast.

    Out west, the Marginal Risk was extended northwest to include the
    Missouri River valley in eastern Nebraska and Kansas, as well as
    western Iowa and Missouri, including the KC Metro. This is
    primarily for heavy but slow moving storms that have developed in
    this area from an overnight MCS.

    Finally, the Slight Risk in Colorado was expanded south to include
    the extreme northeastern fringe of New Mexico, where afternoon
    showers and thunderstorms that will be at least initially tied to
    the terrain may cause widely scattered instances of flash flooding.

    Wegman

    ...Previous Discussion...

    ...Northeast...
    Intense rainfall will be on-going over portions of the Northeast as
    the Day 1 period begins at 29/12Z, with some training of cells and
    some places experiencing multiple rounds of heavy rainfall--particularly
    across western Massachusetts, far southern Vermont, and broadly
    across southern New England. Rainfall rates between 1-2"/hr at
    times will be possible through late morning/early afternoon and
    totals of 2-4" (with localized higher amounts possible) are
    expected.

    HREF/RRFS neighborhood probabilities from the 29/00Z runs remained
    high (greater than 80 percent) for 3" totals across
    western/central MA into far southern VT. Probabilities are moderate
    (30-50 percent) for 5" totals.

    Given the setup and risk of significant flash flooding continuing
    from the day 1 period, a Moderate Risk was maintained with few
    changes given the cumulative rainfall amounts. After 30/00Z...the
    intensity of rainfall should subside while also shifting eastward.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow persists with isolated to widely scattered
    convection extending from the Four Corners region northward and eastward...perhaps extending as far east as the plains of Colorado.
    Some of this rain could fall atop soils saturated from heavy rain
    prior to the start of the Day 1 period at 29/12Z. Persistence in
    the pattern and moisture distribution leaves the risk area in good
    shape with the Slight Risk focused on eastern Colorado.

    ...Central Gulf Coast Region into parts of the Southeast...
    A cold front stalling along the Gulf Coast will be a focus for slow
    moving and training thunderstorms today into tonight. Guidance
    continues to indicate a low-probability threat for at least 3" of
    rain due to training of 1-2"/hr rain rates within favorable
    thermodynamics. This region can generally tolerate significant rain
    rates and this amount of rainfall, but any more pronounced
    training could result in isolated flash flood related impacts.

    Taylor/Bann


    Day 2
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    ...2030Z Update...

    No major changes were needed with this afternoon's update. The
    Slight Risk over the Plains and Midwest was expanded westward with
    the latest update due to guidance moving the area of heaviest
    rainfall westward as compared to prior forecasts. Otherwise, few
    changes were needed. The heaviest rains through the period continue
    to be forecast from northeastern Nebraska through southwestern
    Minnesota.

    Storm coverage and intensity across the 4 Corners region appears
    significantly muted as compared with previous days. The Marginal
    Risk in the area was trimmed back to portions of Arizona and New
    Mexico as a result.

    A moisture feed from the Gulf will allow for a few storms to form
    over western Arkansas and into the Lower Mississippi Valley. The
    Marginal Risks were combined along the front.

    Lingering moisture along the New England coast could continue to
    pose an isolated flash flooding threat, so the Marginal was
    maintained and expanded a bit over southeastern Massachusetts,
    Rhode Island, and eastern Connecticut.

    Wegman

    ...Previous Discussion...

    ...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains on Thursday into
    Thursday night/early Friday morning. The shortwave energy will be
    encountering an increasingly moist and unstable airmass with
    precipitable water values in excess of 2 inches being drawn into
    the region ahead of the shortwave. Given the MCS/upscale growth
    potential with this system, concentrated areas of heavy rain are
    expected given the potential for training and repeat-convection. The
    Slight Risk remained in good shape and only minor adjustments were
    needed to covers the 29/00Z ensemble guidance and to account for
    the uncertainty/spread among the models.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front...especially over parts of Florida and
    Georgia near the state line.

    ...New England...
    The departing low pressure is expected to be across eastern MA at
    the start of the period and transition off the coast during the
    period. Locally heavy rainfall will remain possible across the
    region given its proximity and ample moisture to work with. While
    the instability will likely be less compared to Tuesday/Wednesday,
    the stronger dynamics at play and potential for training rainfall
    could lead to a localized threat, particularly if over areas more
    saturated from previous rainfall. A Marginal Risk was maintained.

    Taylor/Bann


    Day 3
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...2030Z Update...

    A small increase in coverage of heavy rain across the Mid-
    Mississippi Valley led to a small expansion of the Slight to cover
    portions of eastern Missouri and western Kentucky with this update.
    The heaviest rains continue to be focused into far eastern Iowa,
    northwestern Illinois and southwestern Wisconsin, where no changes
    were made as the forecast remains on track.

    Elsewhere, some small adjustments of the MRGL to remove portions of northwestern New Mexico and include more of the Texas Panhandle
    were made, but total coverage and intensity of storms in these
    areas remains little changed.

    Wegman

    ...Previous Discussion...

    Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms on Friday morning. The flow pattern on the northern
    part of the upper high anchored to its west sharpens during the
    day...which induces a turn to the south for the northern Plains
    system. Tended to follow the numerical guidance for placement of
    the Marginal and Slight risk areas where the synoptic scale forcing
    is greatest. This necessitated a bit more eastward nudging from
    the previous outlook. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance. Both the GFS and ECMWF placed their axis of highest precipitable water (1.8 to 2.2 inches) near the Mississippi River
    early in the period which gets deflected towards the Tennessee
    Valley by early Saturday morning.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall is possible in proximity to an
    east-west oriented quasi-stationary front that had been associated
    with a Northeast US cyclone in previous days. Deep-layer moisture
    and instability should be more than sufficient and the guidance
    shows sufficient effective bulk shear (0-6km magnitudes generally
    over 20 kts) for more organized/persistent convective organization.
    As a result, maintained the inherited Marginal Risk .

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 4 and Day 5

    Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL SATURDAY OVER
    PORTIONS OF THE OHIO AND TENNESSEE VALLEYS...

    2030Z Update...
    Extended the Day 4 Slight Risk farther south from the Ohio into the
    Tennessee Valley. Storms are expected to develop ahead of the cold
    front associated with the shortwave trough moving through the
    Midwest on Saturday. The model spread with regards to where the
    better forcing will focus and its potential impact on the
    development of heavier amounts is notable. However, the 12Z
    guidance presented enough of a signal to warrant extending the
    Slight Risk farther south. Storms that develop in this area will
    have access to deeper moisture (PWs ~2-2.25 inches) and likely
    greater instability, supporting heavy rates.

    Elsewhere, made only minor adjustments to outlook areas on both
    days.

    Pereira

    ...Ohio and Tennessee Valleys into parts of the Southeast...
    On Day 4 (Sat-Sat night), rather significant changes were made to
    yesterday's Day 5 ERO, based on the latest guidance trends.
    Specifically, the globals and most ensembles show the upper trough
    amplifying somewhat with the influx of shortwave
    energy/convectively- aided vort lobes dropping southeast. However,
    most of the guidance show less amplification compared to last
    night's runs, with more of a positive to neutral tilt to the trough
    vs. negative. This in turn is allowing for a more progressive
    west-to-east shift in the pre- frontal rainfall east of the
    Mississippi, supported (perhaps led by) both the GFS and ECMWF AI
    models. Therefore the Marginal Risk and encompassing Slight Risk
    areas were shifted east as well, with the Slight Risk confined to
    mainly the northern areas (OH Valley into Cumberland Plateau) per
    the ECMWF and GFS AI trends, along with the highest 24hr QPF
    exceedance probabilities per the 00Z ECENS, and where there is a
    signal (albeit weak) per the most recent ECMWF EFI. The Slight Risk
    is also in an area with comparatively lower 1/3/6 hr FFG vs. areas
    farther south.

    ...Interior Northeast...
    Aforementioned longwave 500 mb trough does begin to take on a more
    neutral to negative tilt on Day 5 (Sun-Sun night) per both the GFS
    and ECMWF. As this occurs, the eastward progression of the
    favorable pre-trough/front dynamical forcing and associated
    moisture axis (PWs of 1.75-2.00") will begin to slow considerably,
    thereby allowing for multiple rounds of moderate-heavy rainfall.
    For now, have hoisted a Marginal Risk across this region on Day 5,
    as the maximum 24hr deterministic QPFs from the latest global runs
    are still (for the time being) under 3".

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain a
    Marginal (isolated) excessive rainfall risk over eastern AZ and
    much of NM into south-central CO on Day 4. By Day 5 (Sun-Sun
    night), both the deterministic and probabilistic QPFs per the
    global and AI guidance would support a smaller MGNL Risk area.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization. As a result, have maintained the inherited Marginal
    Risk on Day 4 (Sat-Sat night), with a similar Marginal Risk area
    on Day 5 (Sun-Sun night).

    Hurley


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4lEDIBzv8H50wgDc9dk9cPTBLPPHJ7HyDuk2ifKlcwhUPSR1zEhSjMQ2xOHldB-u_QSfyYhtuiqhFu58lijhzfu2awQ$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4lEDIBzv8H50wgDc9dk9cPTBLPPHJ7HyDuk2ifKlcwhUPSR1zEhSjMQ2xOHldB-u_QSfyYhtuiqhFu58lijhO3H1HhI$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4lEDIBzv8H50wgDc9dk9cPTBLPPHJ7HyDuk2ifKlcwhUPSR1zEhSjMQ2xOHldB-u_QSfyYhtuiqhFu58lijhyDVbzjY$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Jul 30 08:29:18 2026
    FOUS30 KWBC 300828
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    428 AM EDT Thu Jul 30 2026

    Day 1
    Valid 12Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains today into early
    Friday morning. The shortwave energy will be encountering an
    increasingly moist and unstable airmass with precipitable water
    values in excess of 2 inches being drawn ahead of the shortwave.
    Model guidance still reflected an increased risk for excessive
    rainfall over portions of Arkansas and the outlook area was largely
    left unchanged in this cycle. Concentrated areas of heavy rain are
    expected given the potential for training and repeat- convection.
    The Slight Risk remained in good shape and only minor adjustments
    were needed.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front during the afternoon and evening hours.

    ...New England...
    A low pressure system located along the southern New England coast
    at the start of the outlook period will take a turn to the
    northeast and head out to sea later today. Locally heavy rainfall
    will remain possible across the region given its proximity and
    ample moisture to work with. While the instability will likely be
    less compared to Tuesday/Wednesday, the stronger dynamics at play
    and potential for training rainfall could lead to a localized
    threat, particularly if over areas more saturated from previous
    rainfall. A Marginal Risk was maintained.

    Bann


    Day 2
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms as the Day 2 period begins at 12Z on Friday. The
    system will start taking a southward track in response to upscale
    ridging across Montana and nearby areas of southern Canada. The
    placement of the Marginal and Slight risk areas were similar to the
    previous outlook and saw little reason to stray far from the
    adjustments that were made on Wednesday because there was still
    good agreement with where the synoptic scale forcing will be
    greatest. The southern portion of the Marginal risk area remained
    closer to the placement of greater instability which would support
    higher intensity rainfall rates. Any downpours across that region
    may at least have a chance at challenging the flash flood guidance.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall remains possible along and near
    an east to west oriented quasi-stationary front. Deep- layer
    moisture and instability should be more than sufficient and the
    guidance shows sufficient effective bulk shear (0-6km magnitudes
    generally over 20 kts) for more organized/persistent convective
    organization. As a result, no changes to the Marginal Risk area
    already issued.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 3
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO AND TENNESSEE VALLEYS...

    Ohio and Tennesee Valleys To Parts of the Southeast US...

    The transport of moisture northward from the Gulf will only
    increase on Saturday ahead ofan amplifying mid- and upper-level
    trough approaches from the west. This sets up the possibility for
    heavy to excessive rainfall from parts of the Ohio and Tennessee
    Valley and southward into the Southeast states from Saturday to
    early Sunday morning. The spread in model deterministic QPF and
    from the ensemble neighborhood probability of exceedance plots
    remained large...which seemingly led to only modest QPF amounts in
    blended QPF solutions. With the mid-level wave approaching 2
    standardized anomalies and the precipitable water still forecast to
    be in the 2 to 2.25 inches range...think there is more potential
    for heavy rainfall than not. Expanded the Slight Risk area
    southward but not to the point where the 1- and 3-hour flash flood
    guidance exceeds 4 inches per 3 hours.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will persist over
    much of the Four Corners region and adjacent areas. Once
    again...WPC maintained a Marginal excessive rainfall area here
    without much change in coverage due to forecast reasoning remaining
    the same.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    Bann


    Day 4 and Day 5

    Valid 12Z Sun Aug 02 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NORTHEAST
    PENNSYLVANIA INTO NORTHERN NEW YORK STATE...

    An axis of anomalous PW likely along and ahead of the cold front
    expected to push out of the eastern Lakes into the northeast in the
    Sunday to Monday time frame. There is the beginning of model
    divergence with the evolution of the upper trof and the details of
    how the trof splits into northern and southern components,
    affecting the timing in the models with the eastward push of the
    front and the associated precip. However, overall favorable upper
    dynamics in the anomalous PW axis should support active convection
    along and ahead of this front, with potential for a period of
    training in the moist low level southwest flow parallel to the
    front. A slight risk was introduced for heavy rain potential that
    may fall across areas with reduced FFG values from the recent very
    heavy rainfall amounts from northeast PA into northern NY State.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into southwest New
    Mexico. Not a lot of confidence with qpf details here, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    By day 5...there are more significant model differences with the
    evolution of the upper trof across large portions of the east. The
    GFS is keeping the southern component of this trof stronger and
    farther north than much of the other guidance and has a more
    significant heavy rain foot print from NC into southern New England.
    While confidence is low with any one solution, there is still
    potential for heavy precip in the anomalous PW axis that will
    continue ahead of this upper trof. Some of this may fall across
    portions of southern New England and the northern Mid- Atlantic
    that have lowered FFG values from recent heavy rains. However,
    given the low confidence in the mid to upper level trof evolution,
    at this time range, only a marginal risk is depicted from central
    NC, northeastward through the coastal Mid-Atlantic into southern NY
    State and southern New England.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6_5RNq1jcb7R9CR84MIne4d5r3hdYE2HMZkoLpetLmGSOGzh9OsZ9GE0X5316U68ZEip8XfD0kyM63SwH6lRLMH0csU$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6_5RNq1jcb7R9CR84MIne4d5r3hdYE2HMZkoLpetLmGSOGzh9OsZ9GE0X5316U68ZEip8XfD0kyM63SwH6lRT--NYCE$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6_5RNq1jcb7R9CR84MIne4d5r3hdYE2HMZkoLpetLmGSOGzh9OsZ9GE0X5316U68ZEip8XfD0kyM63SwH6lRVfPsojg$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Jul 30 15:58:32 2026
    FOUS30 KWBC 301558
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1158 AM EDT Thu Jul 30 2026

    Day 1
    Valid 16Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    ...16z Update...

    The day 1 outlook areas remain mostly the same with some minor
    adjustments. The latest 12z hi-res guidance has trended higher with
    QPF amounts over portions of the Northern Plains/Upper Midwest. A
    squall line is still expected to develop over southern/central
    South Dakota and propagate east-southeastward. Precipitable water
    percentiles are expected to be at a maximum (2"+) and instability
    between 2000-3000 J/Kg over these areas, which should support an
    enhanced slight risk area for portions of eastern South Dakota,
    northeastern Nebraska, southwestern Minnesota and far northwestern
    Iowa.

    Kebede

    ...Previous Discussion...

    Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains today into early
    Friday morning. The shortwave energy will be encountering an
    increasingly moist and unstable airmass with precipitable water
    values in excess of 2 inches being drawn ahead of the shortwave.
    Model guidance still reflected an increased risk for excessive
    rainfall over portions of Arkansas and the outlook area was largely
    left unchanged in this cycle. Concentrated areas of heavy rain are
    expected given the potential for training and repeat- convection.
    The Slight Risk remained in good shape and only minor adjustments
    were needed.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front during the afternoon and evening hours.

    ...New England...
    A low pressure system located along the southern New England coast
    at the start of the outlook period will take a turn to the
    northeast and head out to sea later today. Locally heavy rainfall
    will remain possible across the region given its proximity and
    ample moisture to work with. While the instability will likely be
    less compared to Tuesday/Wednesday, the stronger dynamics at play
    and potential for training rainfall could lead to a localized
    threat, particularly if over areas more saturated from previous
    rainfall. A Marginal Risk was maintained.

    Bann


    Day 2
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms as the Day 2 period begins at 12Z on Friday. The
    system will start taking a southward track in response to upscale
    ridging across Montana and nearby areas of southern Canada. The
    placement of the Marginal and Slight risk areas were similar to the
    previous outlook and saw little reason to stray far from the
    adjustments that were made on Wednesday because there was still
    good agreement with where the synoptic scale forcing will be
    greatest. The southern portion of the Marginal risk area remained
    closer to the placement of greater instability which would support
    higher intensity rainfall rates. Any downpours across that region
    may at least have a chance at challenging the flash flood guidance.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall remains possible along and near
    an east to west oriented quasi-stationary front. Deep- layer
    moisture and instability should be more than sufficient and the
    guidance shows sufficient effective bulk shear (0-6km magnitudes
    generally over 20 kts) for more organized/persistent convective
    organization. As a result, no changes to the Marginal Risk area
    already issued.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 3
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO AND TENNESSEE VALLEYS...

    Ohio and Tennesee Valleys To Parts of the Southeast US...

    The transport of moisture northward from the Gulf will only
    increase on Saturday ahead ofan amplifying mid- and upper-level
    trough approaches from the west. This sets up the possibility for
    heavy to excessive rainfall from parts of the Ohio and Tennessee
    Valley and southward into the Southeast states from Saturday to
    early Sunday morning. The spread in model deterministic QPF and
    from the ensemble neighborhood probability of exceedance plots
    remained large...which seemingly led to only modest QPF amounts in
    blended QPF solutions. With the mid-level wave approaching 2
    standardized anomalies and the precipitable water still forecast to
    be in the 2 to 2.25 inches range...think there is more potential
    for heavy rainfall than not. Expanded the Slight Risk area
    southward but not to the point where the 1- and 3-hour flash flood
    guidance exceeds 4 inches per 3 hours.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will persist over
    much of the Four Corners region and adjacent areas. Once
    again...WPC maintained a Marginal excessive rainfall area here
    without much change in coverage due to forecast reasoning remaining
    the same.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    Bann


    Day 4 and Day 5

    Valid 12Z Sun Aug 02 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NORTHEAST
    PENNSYLVANIA INTO NORTHERN NEW YORK STATE...

    An axis of anomalous PW likely along and ahead of the cold front
    expected to push out of the eastern Lakes into the northeast in the
    Sunday to Monday time frame. There is the beginning of model
    divergence with the evolution of the upper trof and the details of
    how the trof splits into northern and southern components,
    affecting the timing in the models with the eastward push of the
    front and the associated precip. However, overall favorable upper
    dynamics in the anomalous PW axis should support active convection
    along and ahead of this front, with potential for a period of
    training in the moist low level southwest flow parallel to the
    front. A slight risk was introduced for heavy rain potential that
    may fall across areas with reduced FFG values from the recent very
    heavy rainfall amounts from northeast PA into northern NY State.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into southwest New
    Mexico. Not a lot of confidence with qpf details here, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    By day 5...there are more significant model differences with the
    evolution of the upper trof across large portions of the east. The
    GFS is keeping the southern component of this trof stronger and
    farther north than much of the other guidance and has a more
    significant heavy rain foot print from NC into southern New England.
    While confidence is low with any one solution, there is still
    potential for heavy precip in the anomalous PW axis that will
    continue ahead of this upper trof. Some of this may fall across
    portions of southern New England and the northern Mid- Atlantic
    that have lowered FFG values from recent heavy rains. However,
    given the low confidence in the mid to upper level trof evolution,
    at this time range, only a marginal risk is depicted from central
    NC, northeastward through the coastal Mid-Atlantic into southern NY
    State and southern New England.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!9lkFGoKTynQm2_vjuwmz3KN9_CFip8XsekxyCJViuGXdFHTd2zx8xAnKqMv1pRPs2rdvBsIZLuFKq2pTZqWVnrOyCGk$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!9lkFGoKTynQm2_vjuwmz3KN9_CFip8XsekxyCJViuGXdFHTd2zx8xAnKqMv1pRPs2rdvBsIZLuFKq2pTZqWVDTnWdMU$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!9lkFGoKTynQm2_vjuwmz3KN9_CFip8XsekxyCJViuGXdFHTd2zx8xAnKqMv1pRPs2rdvBsIZLuFKq2pTZqWVEhRszj0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Jul 30 20:13:24 2026
    FOUS30 KWBC 302012
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    412 PM EDT Thu Jul 30 2026

    Day 1
    Valid 16Z Thu Jul 30 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    ...16z Update...

    The day 1 outlook areas remain mostly the same with some minor
    adjustments. The latest 12z hi-res guidance has trended higher with
    QPF amounts over portions of the Northern Plains/Upper Midwest. A
    squall line is still expected to develop over southern/central
    South Dakota and propagate east-southeastward. Precipitable water
    percentiles are expected to be at a maximum (2"+) and instability
    between 2000-3000 J/Kg over these areas, which should support an
    enhanced slight risk area for portions of eastern South Dakota,
    northeastern Nebraska, southwestern Minnesota and far northwestern
    Iowa.

    Kebede

    ...Previous Discussion...

    Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains today into early
    Friday morning. The shortwave energy will be encountering an
    increasingly moist and unstable airmass with precipitable water
    values in excess of 2 inches being drawn ahead of the shortwave.
    Model guidance still reflected an increased risk for excessive
    rainfall over portions of Arkansas and the outlook area was largely
    left unchanged in this cycle. Concentrated areas of heavy rain are
    expected given the potential for training and repeat- convection.
    The Slight Risk remained in good shape and only minor adjustments
    were needed.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front during the afternoon and evening hours.

    ...New England...
    A low pressure system located along the southern New England coast
    at the start of the outlook period will take a turn to the
    northeast and head out to sea later today. Locally heavy rainfall
    will remain possible across the region given its proximity and
    ample moisture to work with. While the instability will likely be
    less compared to Tuesday/Wednesday, the stronger dynamics at play
    and potential for training rainfall could lead to a localized
    threat, particularly if over areas more saturated from previous
    rainfall. A Marginal Risk was maintained.

    Bann


    Day 2
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...2030z Update...

    The inherited slight risk was expanded into central Iowa/Missouri
    and the Chicago Metro area based on the latest hi-res trends.
    Moisture (2"+ & 99th+ percentile PWATs) will be sufficient enough
    to produce efficient rain rates, however, higher instability may
    not make its way far enough north to help realize higher rates.
    Flash flood guidance around 1" will allow for any convection/heavy
    rainfall to potentially produce flash flooding.

    The marginal in the Southwest remains unchanged, however diurnal
    monsoonal convection that develops over northeastern New Mexico is
    expected to dive south and generate isolated to scattered flash
    flooding in eastern portions of the state.

    Kebede

    ...Previous Discussion...

    ...Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms as the Day 2 period begins at 12Z on Friday. The
    system will start taking a southward track in response to upscale
    ridging across Montana and nearby areas of southern Canada. The
    placement of the Marginal and Slight risk areas were similar to the
    previous outlook and saw little reason to stray far from the
    adjustments that were made on Wednesday because there was still
    good agreement with where the synoptic scale forcing will be
    greatest. The southern portion of the Marginal risk area remained
    closer to the placement of greater instability which would support
    higher intensity rainfall rates. Any downpours across that region
    may at least have a chance at challenging the flash flood guidance.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall remains possible along and near
    an east to west oriented quasi-stationary front. Deep- layer
    moisture and instability should be more than sufficient and the
    guidance shows sufficient effective bulk shear (0-6km magnitudes
    generally over 20 kts) for more organized/persistent convective
    organization. As a result, no changes to the Marginal Risk area
    already issued.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 3
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO/TENNESSEE VALLEYS and eastern New Mexico...

    ...2030z Update...

    ...Ohio/Tennessee Valley...

    The slight risk over the Ohio Valley was expanded west into eastern
    Illinois to account for increasing QPF trends in both the
    deterministic GFS and Euro. A potent mid-latitude cyclone is still
    on track to supply ample instability into the Midwest on Saturday
    night, beneath a deepening positively tilted mid-level low. Storms
    will propagate from the Upper Midwest on Saturday into the
    Ohio/Tennessee Valleys on Sunday amidst this strengthening system
    aloft.

    ...New Mexico...

    The slight risk in New Mexico is maintained but shifted south a bit
    based on the latest model guidance. North-to-south storm motion
    within an increasingly moist environment (1"+ and 97.5th
    percentile PWATs) and relatively saturated soils from Friday storms
    will contribute to the flash flooding threat.

    Kebede

    ...Previous Discussion...

    ...Ohio and Tennesee Valleys To Parts of the Southeast US...

    The transport of moisture northward from the Gulf will only
    increase on Saturday ahead of an amplifying mid- and upper-level
    trough approaches from the west. This sets up the possibility for
    heavy to excessive rainfall from parts of the Ohio and Tennessee
    Valley and southward into the Southeast states from Saturday to
    early Sunday morning. The spread in model deterministic QPF and
    from the ensemble neighborhood probability of exceedance plots
    remained large...which seemingly led to only modest QPF amounts in
    blended QPF solutions. With the mid-level wave approaching 2
    standardized anomalies and the precipitable water still forecast to
    be in the 2 to 2.25 inches range...think there is more potential
    for heavy rainfall than not. Expanded the Slight Risk area
    southward but not to the point where the 1- and 3-hour flash flood
    guidance exceeds 4 inches per 3 hours.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will persist over
    much of the Four Corners region and adjacent areas. Once
    again...WPC maintained a Marginal excessive rainfall area here
    without much change in coverage due to forecast reasoning remaining
    the same.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    Bann


    Day 4 and Day 5

    Valid 12Z Sun Aug 02 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER EASTERN
    PORTIONS OF THE UPPER GREAT LAKES AND THE UPPER OHIO VALLEY...

    2030Z Update...
    Following the general trend shown by several 12Z runs toward a more quickly-amplifying, slower solution, shifted the outlook areas
    farther west -- centering the Slight Risk more over the lower Great
    Lake/upper Ohio Valley region and extending it back into
    southeastern Lower Michigan.

    Also added a Marginal Risk to parts of the eastern Gulf Coast on
    both days. A deep moisture pool (PWs 2.25-2.5+ inches) ahead of a
    low level boundary will support storms capable of producing
    highly-efficient rainfall rates and heavy amounts. The greater
    threat for heavy rainfall is expected to extend across the Florida
    Panhandle into North Florida on Day 4, with the threat waning on
    the western edge on Day 5 as the boundary and axis of deepest
    moisture slowly drifts east.

    Pereira

    Previous Discussion...
    An axis of anomalous PW likely along and ahead of the cold front
    expected to push out of the eastern Lakes into the northeast in the
    Sunday to Monday time frame. There is the beginning of model
    divergence with the evolution of the upper trof and the details of
    how the trof splits into northern and southern components,
    affecting the timing in the models with the eastward push of the
    front and the associated precip. However, overall favorable upper
    dynamics in the anomalous PW axis should support active convection
    along and ahead of this front, with potential for a period of
    training in the moist low level southwest flow parallel to the
    front. A slight risk was introduced for heavy rain potential that
    may fall across areas with reduced FFG values from the recent very
    heavy rainfall amounts from northeast PA into northern NY State.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into southwest New
    Mexico. Not a lot of confidence with qpf details here, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    By day 5...there are more significant model differences with the
    evolution of the upper trof across large portions of the east. The
    GFS is keeping the southern component of this trof stronger and
    farther north than much of the other guidance and has a more
    significant heavy rain foot print from NC into southern New England.
    While confidence is low with any one solution, there is still
    potential for heavy precip in the anomalous PW axis that will
    continue ahead of this upper trof. Some of this may fall across
    portions of southern New England and the northern Mid- Atlantic
    that have lowered FFG values from recent heavy rains. However,
    given the low confidence in the mid to upper level trof evolution,
    at this time range, only a marginal risk is depicted from central
    NC, northeastward through the coastal Mid-Atlantic into southern NY
    State and southern New England.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4F1NKxcobe_glD8GPHas4xjDVSPdHi76CxEAQtfqOkLl6Qf5lo6C8NwCX_plY0VNsp_W2FUdIk3RZBsmU0y2laIRo20$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4F1NKxcobe_glD8GPHas4xjDVSPdHi76CxEAQtfqOkLl6Qf5lo6C8NwCX_plY0VNsp_W2FUdIk3RZBsmU0y2bGaND4g$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4F1NKxcobe_glD8GPHas4xjDVSPdHi76CxEAQtfqOkLl6Qf5lo6C8NwCX_plY0VNsp_W2FUdIk3RZBsmU0y20QnFl24$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Jul 31 00:57:44 2026
    FOUS30 KWBC 310057
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    857 PM EDT Thu Jul 30 2026

    Day 1
    Valid 01Z Fri Jul 31 2026 - 12Z Fri Jul 31 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MID TO LOWER MISSOURI AND MID TO UPPER MISSISSIPPI VALLEYS...

    ...01Z Update...

    Current observation trends, recent HRRR runs, and the latest
    HREF/REFS did not suggest any large-scale changes were required for
    much of the ERO. The HRRR, HREF, and REFS are in generally good
    agreement, indicating one of the greater overnight heavy rainfall
    and flash flooding threats is likely to center from eastern South
    Dakota to south-central Minnesota. Slow-moving, highly-efficient
    cells are expected to continue to develop and produce heavy rates
    with an increasing potential for flash flooding during the
    overnight hours. Deep warm cloud layers and PWs around 2 inches,
    sustained by southerly flow, will support heavy rates (2-3 in/hr),
    with the heavy accumulation and flash flooding threat elevated by
    slow storm movements. The HREF shows neighborhood probabilities
    greater than 50 percent for amounts over 3 inches along an axis
    from eastern South Dakota, where storms have already to developed,
    into southwestern to south-central Minnesota. Along this axis, the
    HREF is also showing some lower probabilities (~40 percent) for
    amounts exceeding 5 inches overnight.

    In the Northeast, the Marginal Risk was removed, where scattered
    showers will continue to wane in coverage and intensity.

    Pereira

    ...16z Update...

    The day 1 outlook areas remain mostly the same with some minor
    adjustments. The latest 12z hi-res guidance has trended higher with
    QPF amounts over portions of the Northern Plains/Upper Midwest. A
    squall line is still expected to develop over southern/central
    South Dakota and propagate east-southeastward. Precipitable water
    percentiles are expected to be at a maximum (2"+) and instability
    between 2000-3000 J/Kg over these areas, which should support an
    enhanced slight risk area for portions of eastern South Dakota,
    northeastern Nebraska, southwestern Minnesota and far northwestern
    Iowa.

    Kebede

    ...Previous Discussion...

    Lower Missouri Valley into the Mid-Upper Mississippi Valley...
    Shortwave energy will be progressing east southeast as it tracks
    across parts of the central and northern plains today into early
    Friday morning. The shortwave energy will be encountering an
    increasingly moist and unstable airmass with precipitable water
    values in excess of 2 inches being drawn ahead of the shortwave.
    Model guidance still reflected an increased risk for excessive
    rainfall over portions of Arkansas and the outlook area was largely
    left unchanged in this cycle. Concentrated areas of heavy rain are
    expected given the potential for training and repeat- convection.
    The Slight Risk remained in good shape and only minor adjustments
    were needed.

    ...Four Corners States into the Central/Northern Plains...
    Monsoonal flow and anomalous deep-layer moisture will maintain an
    isolated excessive rainfall risk extending from eastern Arizona
    northeastward across much of western and northern New Mexico into
    parts of Colorado. The expanding mid/upper level ridge will likely
    limit the coverage compared to recent days.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall is expected along a front associated with a low
    pressure system which will be pulling away from New England.
    Heavy rainfall with some potential of flooding will be focused
    along and near the front during the afternoon and evening hours.

    Bann


    Day 2
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...2030z Update...

    The inherited slight risk was expanded into central Iowa/Missouri
    and the Chicago Metro area based on the latest hi-res trends.
    Moisture (2"+ & 99th+ percentile PWATs) will be sufficient enough
    to produce efficient rain rates, however, higher instability may
    not make its way far enough north to help realize higher rates.
    Flash flood guidance around 1" will allow for any convection/heavy
    rainfall to potentially produce flash flooding.

    The marginal in the Southwest remains unchanged, however diurnal
    monsoonal convection that develops over northeastern New Mexico is
    expected to dive south and generate isolated to scattered flash
    flooding in eastern portions of the state.

    Kebede

    ...Previous Discussion...

    ...Central US system...
    Shortwave energy initially moving eastward out of the Northern
    Rockies and adjacent High Plains will be accompanied by showers and thunderstorms as the Day 2 period begins at 12Z on Friday. The
    system will start taking a southward track in response to upscale
    ridging across Montana and nearby areas of southern Canada. The
    placement of the Marginal and Slight risk areas were similar to the
    previous outlook and saw little reason to stray far from the
    adjustments that were made on Wednesday because there was still
    good agreement with where the synoptic scale forcing will be
    greatest. The southern portion of the Marginal risk area remained
    closer to the placement of greater instability which would support
    higher intensity rainfall rates. Any downpours across that region
    may at least have a chance at challenging the flash flood guidance.

    ...Central Gulf Coast Region into parts of the Southeast...
    Locally heavy to excessive rainfall remains possible along and near
    an east to west oriented quasi-stationary front. Deep- layer
    moisture and instability should be more than sufficient and the
    guidance shows sufficient effective bulk shear (0-6km magnitudes
    generally over 20 kts) for more organized/persistent convective
    organization. As a result, no changes to the Marginal Risk area
    already issued.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern AZ and much of New Mexico into Colorado. The
    areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge.

    Bann


    Day 3
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO/TENNESSEE VALLEYS and eastern New Mexico...

    ...2030z Update...

    ...Ohio/Tennessee Valley...

    The slight risk over the Ohio Valley was expanded west into eastern
    Illinois to account for increasing QPF trends in both the
    deterministic GFS and Euro. A potent mid-latitude cyclone is still
    on track to supply ample instability into the Midwest on Saturday
    night, beneath a deepening positively tilted mid-level low. Storms
    will propagate from the Upper Midwest on Saturday into the
    Ohio/Tennessee Valleys on Sunday amidst this strengthening system
    aloft.

    ...New Mexico...

    The slight risk in New Mexico is maintained but shifted south a bit
    based on the latest model guidance. North-to-south storm motion
    within an increasingly moist environment (1"+ and 97.5th
    percentile PWATs) and relatively saturated soils from Friday storms
    will contribute to the flash flooding threat.

    Kebede

    ...Previous Discussion...

    ...Ohio and Tennesee Valleys To Parts of the Southeast US...

    The transport of moisture northward from the Gulf will only
    increase on Saturday ahead of an amplifying mid- and upper-level
    trough approaches from the west. This sets up the possibility for
    heavy to excessive rainfall from parts of the Ohio and Tennessee
    Valley and southward into the Southeast states from Saturday to
    early Sunday morning. The spread in model deterministic QPF and
    from the ensemble neighborhood probability of exceedance plots
    remained large...which seemingly led to only modest QPF amounts in
    blended QPF solutions. With the mid-level wave approaching 2
    standardized anomalies and the precipitable water still forecast to
    be in the 2 to 2.25 inches range...think there is more potential
    for heavy rainfall than not. Expanded the Slight Risk area
    southward but not to the point where the 1- and 3-hour flash flood
    guidance exceeds 4 inches per 3 hours.

    ...Four Corners States into the Southern-Central High Plains...
    Monsoonal flow and anomalous deep-layer moisture will persist over
    much of the Four Corners region and adjacent areas. Once
    again...WPC maintained a Marginal excessive rainfall area here
    without much change in coverage due to forecast reasoning remaining
    the same.

    ...Central Gulf Coast Region into parts of the Southeast...
    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    Bann


    Day 4 and Day 5

    Valid 12Z Sun Aug 02 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER EASTERN
    PORTIONS OF THE UPPER GREAT LAKES AND THE UPPER OHIO VALLEY...

    2030Z Update...
    Following the general trend shown by several 12Z runs toward a more quickly-amplifying, slower solution, shifted the outlook areas
    farther west -- centering the Slight Risk more over the lower Great
    Lake/upper Ohio Valley region and extending it back into
    southeastern Lower Michigan.

    Also added a Marginal Risk to parts of the eastern Gulf Coast on
    both days. A deep moisture pool (PWs 2.25-2.5+ inches) ahead of a
    low level boundary will support storms capable of producing
    highly-efficient rainfall rates and heavy amounts. The greater
    threat for heavy rainfall is expected to extend across the Florida
    Panhandle into North Florida on Day 4, with the threat waning on
    the western edge on Day 5 as the boundary and axis of deepest
    moisture slowly drifts east.

    Pereira

    Previous Discussion...
    An axis of anomalous PW likely along and ahead of the cold front
    expected to push out of the eastern Lakes into the northeast in the
    Sunday to Monday time frame. There is the beginning of model
    divergence with the evolution of the upper trof and the details of
    how the trof splits into northern and southern components,
    affecting the timing in the models with the eastward push of the
    front and the associated precip. However, overall favorable upper
    dynamics in the anomalous PW axis should support active convection
    along and ahead of this front, with potential for a period of
    training in the moist low level southwest flow parallel to the
    front. A slight risk was introduced for heavy rain potential that
    may fall across areas with reduced FFG values from the recent very
    heavy rainfall amounts from northeast PA into northern NY State.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into southwest New
    Mexico. Not a lot of confidence with qpf details here, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    By day 5...there are more significant model differences with the
    evolution of the upper trof across large portions of the east. The
    GFS is keeping the southern component of this trof stronger and
    farther north than much of the other guidance and has a more
    significant heavy rain foot print from NC into southern New England.
    While confidence is low with any one solution, there is still
    potential for heavy precip in the anomalous PW axis that will
    continue ahead of this upper trof. Some of this may fall across
    portions of southern New England and the northern Mid- Atlantic
    that have lowered FFG values from recent heavy rains. However,
    given the low confidence in the mid to upper level trof evolution,
    at this time range, only a marginal risk is depicted from central
    NC, northeastward through the coastal Mid-Atlantic into southern NY
    State and southern New England.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8D3_igmj704A5V_knMHbMGtO1IppxSFUFoSOecWXiGhbRjAuC_BKLzqPBhiID3ElkJiAGCKFFrn5IQ1pc9sbwTZGUEE$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8D3_igmj704A5V_knMHbMGtO1IppxSFUFoSOecWXiGhbRjAuC_BKLzqPBhiID3ElkJiAGCKFFrn5IQ1pc9sbmlxe0_g$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8D3_igmj704A5V_knMHbMGtO1IppxSFUFoSOecWXiGhbRjAuC_BKLzqPBhiID3ElkJiAGCKFFrn5IQ1pc9sbxX0sCIM$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Jul 31 08:19:54 2026
    FOUS30 KWBC 310819
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    419 AM EDT Fri Jul 31 2026

    Day 1
    Valid 12Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    MID TO UPPER MISSISSIPPI VALLEY AND VICINITY...

    ...Central US system...

    Ridging across Montana and the Canadian Prairie will direct
    shortwave energy southeastward spreading showers and thunderstorms
    through the north-central and central states during this period.
    Moisture (2"+ & 99th+ percentile PWATs) will be sufficient enough
    to produce efficient rain rates, however, higher instability may
    not make its way far enough north to help realize higher rates.
    Flash flood guidance around 1" will allow for any convection/heavy
    rainfall to potentially produce flash flooding. A Slight Risk area
    encompasses southeast Minnesota, southern Wisconsin, Illinois,
    western Indiana, northwest Kentucky, eastern Missouri and
    central/eastern Iowa. The southern portion of the Marginal risk
    area remained closer to the placement of greater instability which
    would support higher intensity rainfall rates. Any downpours across
    that region may at least have a chance at challenging the flash
    flood guidance.

    ...Central Gulf Coast Region into parts of the Southeast...

    A quasi-stationary front will be orientated in the west-east
    fashion across the Gulf Coast region and will be a focus for locally
    heavy to excessive rainfall. Deep- layer moisture and instability
    should be more than sufficient and the guidance shows sufficient
    effective bulk shear (0-6km magnitudes generally over 20 kts) for
    more organized/persistent convective organization.

    ...Four Corners States into the Southern-Central High Plains...

    Monsoonal flow and anomalous deep-layer moisture will keep the
    potential for isolated instances of excessive rainfall across
    portions of eastern Arizona and much of New Mexico into Colorado.
    The areal coverage may be less than in preceding days given the
    expansion of the sprawling upper ridge. Diurnal monsoonal
    convection that develops over northeastern New Mexico is expected
    to dive south and generate isolated to scattered flash flooding in
    eastern portions of the state.

    Campbell/Bann


    Day 2
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...Ohio/Tennessee Valley...

    A potent low pressure system will supply plentiful instability to
    the Great Lakes/Ohio and Tennessee Valleys region beneath a
    deepening positively tilted mid-level low. PW values of 2+ standard
    deviations above average (2-2.25 inches) will be advecting into
    the region to support enhanced rainfall. A Slight Risk remains in
    effect from eastern Illinois to Ohio and southward to Alabama and
    Georgia. A broad Marginal Risk spans from Wisconsin to western New
    York south to the eastern Gulf Coast and Southeast.

    ...Central Gulf Coast Region into parts of the Southeast...

    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    ...New Mexico...

    During this period general storm motion is expected to be from
    north to south into an increasingly moist environment (1"+ and
    97.5th percentile PWATs) and relatively saturated soils from Friday
    storms will contribute to the flash flooding threat. A Slight Risk
    was maintained for portions of central/eastern New Mexico with a
    Marginal Risk area stretching from southeast Arizona to western
    Texas and northward to southern Colorado.

    Campbell/Kebede


    Day 3
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE NORTHEAST...

    ...Upper Midwest to Northeast and Mid-Atlantic region...

    The potent mid-level cyclone will continue to track to the east
    during this period ushering the showers and thunderstorms along
    with it into the Lower Great Lakes and Northeast region. Streaks of
    heavy rainfall are also expected to develop across parts of the Mid-Atlantic/North Carolina region. Some of these cells will have the
    potential to yield 2 inches over a short period during the
    afternoon and evening hours. A broad Marginal Risk spans from the
    North/South Carolina border northward to New York and Lower
    Michigan. A Slight Risk area covers extreme southeast Michigan,
    northeast Ohio, northern West Virginia, western Pennsylvania and
    western New York.

    ...Southeast...

    Showers and thunderstorms will persist along the stalled frontal
    boundary thus maintaining an elevated threat for heavy rainfall and
    potential for local flash flooding. Therefore, a Marginal RIsk area
    was maintained for eastern Gulf Coast/northern Florida and southern
    Georgia.

    ...Southwest...

    Monsoonal moisture will continue to drive convection across
    portions of New Mexico and Arizona. Locally heavy rainfall may
    continue to result in isolated flash flooding across the region. A
    Marginal Risk area is in effect for southern Arizona and southwest
    New Mexico.

    Campbell


    Day 4 and Day 5

    Valid 12Z Mon Aug 03 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    The well defined upper trof moving through the Ohio Valley day 3,
    will begin to split into two pieces day 4. While there are
    differences with the details with this upper trof evolution, there
    is agreement that an axis of anomalous PW values, 2+ standard
    deviations above the mean, 2 to 2.25" PW values, will stretch from
    North Florida, northeastward across the coastal Southeast, Mid-
    Atlantic and from eastern NY State into New England. Generally
    favorable right entrance region jet dynamics will accentuate lift
    in this anomalous PW axis, supporting potential for locally heavy
    rainfall totals. A slight risk was added over portions of the
    northern Mid-Atlantic into southern NY State and southern New
    England where recent heavy rains have lowered FFG values. A
    marginal risk extends southward through the remainder of the Mid-
    Atlantic into the Southeast where locally heavy rains are also
    likely but FFG values are higher.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.

    Day 5...the closed low over the Upper OH Valley will become nearly
    stationary day 5. An area of anomalous PW values will remain to the
    east of this closed low, across the Upper OH Valley into the Mid-
    Atlantic, Southern New England and south into the coastal southern Mid-Atlantic. A broad marginal risk area was depicted in this
    anomalous PW axis for locally heavy rains and isolated runoff
    issues. The surface front moving through New England day 4, may
    become stationary and west to east oriented across southern New
    England into the northern Mid-Atlantic day 5. A few models are
    showing more defined heavy rains in the vicinity of this front
    where there is potential for persistent south southwesterly inflow.
    Still a lot of spread with qpf details, warranting only a marginal
    risk at this time, with changes possible with future updates.

    A surface front expected to push southeastward day 5 from the Upper
    MS Valley into the Upper Lakes and south through the Central
    Plains. There is model consensus for an axis of potentially heavy
    rains from Nebraska, eastward into Iowa and southern MN where the
    front may become more west to east oriented late Tue into early
    Wed. Moist southerly low level inflow into the front at this time
    may support organized convection, heavy rains and isolated runoff
    issues.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7K3osG7Gm0gjgVrMAkPbpKXpMndJHQUHXUUtou4b5Jv7GQ9_lb-YpOWRMi_JDx0zjZaZd1nC8atl9M9au6Vyys0hBbo$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7K3osG7Gm0gjgVrMAkPbpKXpMndJHQUHXUUtou4b5Jv7GQ9_lb-YpOWRMi_JDx0zjZaZd1nC8atl9M9au6VyD5_J2QU$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7K3osG7Gm0gjgVrMAkPbpKXpMndJHQUHXUUtou4b5Jv7GQ9_lb-YpOWRMi_JDx0zjZaZd1nC8atl9M9au6VyYDfkjtY$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Jul 31 15:58:24 2026
    FOUS30 KWBC 311558
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1158 AM EDT Fri Jul 31 2026

    Day 1
    Valid 16Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    MID TO UPPER MISSISSIPPI VALLEY, AND THE UPPER PENINSULA OF
    MICHIGAN...

    ...Central US system...
    A potent shortwave diving across the Northern Plains this morning
    will deepen as it ejects southeast into the Upper Midwest by
    Saturday morning. This deepening will create an extremely anomalous
    mid-level low for late July, reflected by NAEFS height anomalies
    falling to below the minimum climatological values at 700mb, and to
    below the 10th percentile at 500mb. An impressively deep system
    overlapping late July thermodynamics is a clear indicator of
    excessive rainfall potential, and this event is no different.

    As the mid-level low dives southeast, it will drive increasing
    downstream ascent through divergence and height falls, with the
    subsequent surface low occluding across Iowa. Within this
    occlusion (and farther downstream warm sector) PWs will climb to
    1.75 to 2.00 inches, above the 90th percentile for the date, and
    overlap with MUCAPE around 1000 J/kg. The accompanying 850mb inflow
    will be locally accelerated to 30-40 kts, drawing these pronounced thermodynamics northward to support heavy rain production within
    thunderstorms. At the same time, the associated theta-e ridge is
    progged to lift cyclonically, creating an impressive (especially
    for the end of July) TROWAL which will pivot atop the Upper
    Midwest. This will not only result in enhanced elevated
    instability, but also support additional moisture to fuel heavy
    rainfall.

    Both the HREF and REFS neighborhood probabilities indicate a 40-70%
    chance for at least hourly rainfall of 1", and although there
    continues to be some latitudinal uncertainty to the placement, the
    consensus of the available high-res CAMs is for locally heavy rain
    rates within a progressive band this morning, becoming more aligned
    for training later today. This is most likely beneath the TROWAL
    where Corfidi vectors and mean 0-6km winds become anti-parallel
    leading to backbuilding/repeating heavy rain rates. The greatest
    risk for 3"/24hrs from the high-res ensembles is from near St.
    Louis, MO northward through southern WI, which is also where there
    are notable probabilities for 5"/24 hrs (30-60%), especially near
    the Quad Cities of IA. This is also where the CSU First-Guess ERO
    field is most aggressive, so despite some dryness in the antecedent
    soils, an elevated SLGT risk is warranted for this region.
    Otherwise, cosmetic adjustments were made to both the SLGT and MRGL
    risks across the region.

    ...Upper Peninsula of Michigan...
    The impressive system moving through the Upper Midwest will result
    in increased deformation between 700-500mb pivoting into the Upper
    Peninsula this aftn/eve. This will encourage enhanced ascent across
    the region, despite a slow wane in MUCAPE noted via the various
    models. The accompanying ascent within this persistent deformation
    axis will support widespread showers and thunderstorms today, which
    despite the waning instability will be fueled by PWs as high as
    1.5 inches, or above the 90th climatological percentile. This will
    support rainfall rates that are progged by both HREF and REFS
    neighborhood probabilities to have a 30-60% chance of exceeding
    1"/hr, which will occur within aligned Corfidi vectors/mean 0-6km
    winds to support training.

    3-hr FFG across the area is generally 1.5 to 2.5 inches which has
    20-40% chance of exceedance. This suggests at least scattered
    instances of flash flooding are possible, but will be most likely
    where any more prolonged training can result in 3 inches (50-60%
    chance) to as much as 5 inches (10-20% chance) of rain. After
    coordination with WFO MQT, a SLGT risk was added for the increased
    excessive rainfall potential today and tonight.

    ...Northern Florida through the Central Gulf Coast...
    Robust late-July thermodynamics characterized by PWs of 2-2.25
    inches and MUCAPE above 2000 J/kg will spread across the area today
    and tonight ahead of a quasi-stationary front. This will likely
    result in two periods of convection capable of producing heavy
    rainfall.

    The first will be during peak heating when airmass
    thunderstorms will develop, aided by a modest vorticity impulse
    digging into MS/AL around the large mid-level ridge to the west.
    Weak shear (less than 20 kts) during this time suggests storms that
    develop will be generally of the pulse variety with limited
    organization and lifespans, but storm mergers, boundary
    collisions, and any locally enhanced ascent in the vicinity of this
    shortwave could increase the overage and intensity of storms during
    the aftn/eve.

    These storms should wane with convective overturning during the
    evening, but a secondary signal has shown up in the guidance for
    late tonight into early Saturday, especially across the Florida
    Panhandle and into the Big Bend area. Here, the aforementioned
    shortwave will slow within an area of thickness diffluence, leading
    to a longer period of enhanced synoptic lift aided by modest jet-
    level diffluence. This ascent acting upon any residual boundaries
    and the land breeze could reignite thunderstorms as the LLJ
    attempts to back subtly more to the WSW from W as the front
    approaches, drawing even more impressive PWs along the coast.
    During this time, Corfidi vectors are progged to collapse to 5 kts
    or less and become increasingly anti-parallel to the mean wind
    suggesting some greater backbuilding/training potential with rain
    rates potentially reaching 3"/hr (10-20% chance). Both the HREF and
    REFS indicate a 20-40% chance for 5" of rainfall from this
    nocturnal event, but the deterministic models are quite different
    in the coverage and placement. At this time, after coordination
    with WFO TAE, the MRGL risk was left unchanged for this area, but
    an upgrade to a targeted SLGT risk may be needed with later
    updates, with the SLGT potentially extending (or being more needed)
    through D2.

    ...Four Corners States into the Southern-Central High Plains...
    The monsoon ridge will get suppressed to the south and west in
    response to the potent system moving through the Plains/Midwest,
    with a secondary piece of vorticity energy dropping across the
    southern High Plains into the Texas Panhandle. This will help push
    a cold front through the Southern Plains and bank against the
    terrain of New Mexico later this evening. The overlapping ascent
    from the cold front and shortwave will act upon favorable
    thermodynamics as a ribbon of PWs above 1.5 inches and pooled
    MUCAPE of 1000-1500 J/kg get drawn westward ahead of the front.

    Coverage of monsoonal thunderstorms may be somewhat less than
    previous days today due to the re-centereing of the ridge. But at
    least scattered diurnal thunderstorms are expected from eastern AZ,
    through NM, and into eastern CO with hourly rainfall up to 1 inch
    at times. The focus for heaviest rain is likely where the
    shortwave/front move into NM/TX Panhandle where some organized
    clusters and better training potential exists. This is reflected by
    both HREF and REFS exceedance probabilities reaching 15-25% (FFG)
    and 30-50% (3"/24hrs). This still supports the inherited MRGL risk,
    and only cosmetic adjustments were made based on the new guidance.

    Weiss/Miller


    Day 2
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FRIDAY ACROSS
    PARTS OF THE UPPER MIDWEST TO MID MISSISSIPPI VALLEY...

    ...Ohio/Tennessee Valley...

    A potent low pressure system will supply plentiful instability to
    the Great Lakes/Ohio and Tennessee Valleys region beneath a
    deepening positively tilted mid-level low. PW values of 2+ standard
    deviations above average (2-2.25 inches) will be advecting into
    the region to support enhanced rainfall. A Slight Risk remains in
    effect from eastern Illinois to Ohio and southward to Alabama and
    Georgia. A broad Marginal Risk spans from Wisconsin to western New
    York south to the eastern Gulf Coast and Southeast.

    ...Central Gulf Coast Region into parts of the Southeast...

    Heavy rainfall threat will continue over this region along the
    southern periphery of the full-latitude trough, south of the
    quasi-sationary front. Deep-layer moisture and instability should
    be more than sufficient, especially when coinciding with the weak
    upper forcing (upstream upper trough w/ embedded convectively-aided shortwaves), for more organized/persistent convective
    organization.

    ...New Mexico...

    During this period general storm motion is expected to be from
    north to south into an increasingly moist environment (1"+ and
    97.5th percentile PWATs) and relatively saturated soils from Friday
    storms will contribute to the flash flooding threat. A Slight Risk
    was maintained for portions of central/eastern New Mexico with a
    Marginal Risk area stretching from southeast Arizona to western
    Texas and northward to southern Colorado.

    Campbell/Kebede


    Day 3
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE NORTHEAST...

    ...Upper Midwest to Northeast and Mid-Atlantic region...

    The potent mid-level cyclone will continue to track to the east
    during this period ushering the showers and thunderstorms along
    with it into the Lower Great Lakes and Northeast region. Streaks of
    heavy rainfall are also expected to develop across parts of the Mid-Atlantic/North Carolina region. Some of these cells will have the
    potential to yield 2 inches over a short period during the
    afternoon and evening hours. A broad Marginal Risk spans from the
    North/South Carolina border northward to New York and Lower
    Michigan. A Slight Risk area covers extreme southeast Michigan,
    northeast Ohio, northern West Virginia, western Pennsylvania and
    western New York.

    ...Southeast...

    Showers and thunderstorms will persist along the stalled frontal
    boundary thus maintaining an elevated threat for heavy rainfall and
    potential for local flash flooding. Therefore, a Marginal RIsk area
    was maintained for eastern Gulf Coast/northern Florida and southern
    Georgia.

    ...Southwest...

    Monsoonal moisture will continue to drive convection across
    portions of New Mexico and Arizona. Locally heavy rainfall may
    continue to result in isolated flash flooding across the region. A
    Marginal Risk area is in effect for southern Arizona and southwest
    New Mexico.

    Campbell


    Day 4 and Day 5

    Valid 12Z Mon Aug 03 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    The well defined upper trof moving through the Ohio Valley day 3,
    will begin to split into two pieces day 4. While there are
    differences with the details with this upper trof evolution, there
    is agreement that an axis of anomalous PW values, 2+ standard
    deviations above the mean, 2 to 2.25" PW values, will stretch from
    North Florida, northeastward across the coastal Southeast, Mid-
    Atlantic and from eastern NY State into New England. Generally
    favorable right entrance region jet dynamics will accentuate lift
    in this anomalous PW axis, supporting potential for locally heavy
    rainfall totals. A slight risk was added over portions of the
    northern Mid-Atlantic into southern NY State and southern New
    England where recent heavy rains have lowered FFG values. A
    marginal risk extends southward through the remainder of the Mid-
    Atlantic into the Southeast where locally heavy rains are also
    likely but FFG values are higher.

    For both day 4 and day 5...a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.

    Day 5...the closed low over the Upper OH Valley will become nearly
    stationary day 5. An area of anomalous PW values will remain to the
    east of this closed low, across the Upper OH Valley into the Mid-
    Atlantic, Southern New England and south into the coastal southern Mid-Atlantic. A broad marginal risk area was depicted in this
    anomalous PW axis for locally heavy rains and isolated runoff
    issues. The surface front moving through New England day 4, may
    become stationary and west to east oriented across southern New
    England into the northern Mid-Atlantic day 5. A few models are
    showing more defined heavy rains in the vicinity of this front
    where there is potential for persistent south southwesterly inflow.
    Still a lot of spread with qpf details, warranting only a marginal
    risk at this time, with changes possible with future updates.

    A surface front expected to push southeastward day 5 from the Upper
    MS Valley into the Upper Lakes and south through the Central
    Plains. There is model consensus for an axis of potentially heavy
    rains from Nebraska, eastward into Iowa and southern MN where the
    front may become more west to east oriented late Tue into early
    Wed. Moist southerly low level inflow into the front at this time
    may support organized convection, heavy rains and isolated runoff
    issues.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4PMAhYmcaXdEv00DnDPRt_nhmEvDCZHo_OSYRusY4QN4JjJKUbRIlNkxtBzKDphriKpRJYaMDWOeAjfPCcwhFqbbW-8$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4PMAhYmcaXdEv00DnDPRt_nhmEvDCZHo_OSYRusY4QN4JjJKUbRIlNkxtBzKDphriKpRJYaMDWOeAjfPCcwh89dUDlM$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4PMAhYmcaXdEv00DnDPRt_nhmEvDCZHo_OSYRusY4QN4JjJKUbRIlNkxtBzKDphriKpRJYaMDWOeAjfPCcwh4mNGUJM$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Jul 31 20:14:12 2026
    FOUS30 KWBC 312013
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    413 PM EDT Fri Jul 31 2026

    Day 1
    Valid 16Z Fri Jul 31 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    MID TO UPPER MISSISSIPPI VALLEY, AND THE UPPER PENINSULA OF
    MICHIGAN...

    ...Central US system...
    A potent shortwave diving across the Northern Plains this morning
    will deepen as it ejects southeast into the Upper Midwest by
    Saturday morning. This deepening will create an extremely anomalous
    mid-level low for late July, reflected by NAEFS height anomalies
    falling to below the minimum climatological values at 700mb, and to
    below the 10th percentile at 500mb. An impressively deep system
    overlapping late July thermodynamics is a clear indicator of
    excessive rainfall potential, and this event is no different.

    As the mid-level low dives southeast, it will drive increasing
    downstream ascent through divergence and height falls, with the
    subsequent surface low occluding across Iowa. Within this
    occlusion (and farther downstream warm sector) PWs will climb to
    1.75 to 2.00 inches, above the 90th percentile for the date, and
    overlap with MUCAPE around 1000 J/kg. The accompanying 850mb inflow
    will be locally accelerated to 30-40 kts, drawing these pronounced thermodynamics northward to support heavy rain production within
    thunderstorms. At the same time, the associated theta-e ridge is
    progged to lift cyclonically, creating an impressive (especially
    for the end of July) TROWAL which will pivot atop the Upper
    Midwest. This will not only result in enhanced elevated
    instability, but also support additional moisture to fuel heavy
    rainfall.

    Both the HREF and REFS neighborhood probabilities indicate a 40-70%
    chance for at least hourly rainfall of 1", and although there
    continues to be some latitudinal uncertainty to the placement, the
    consensus of the available high-res CAMs is for locally heavy rain
    rates within a progressive band this morning, becoming more aligned
    for training later today. This is most likely beneath the TROWAL
    where Corfidi vectors and mean 0-6km winds become anti-parallel
    leading to backbuilding/repeating heavy rain rates. The greatest
    risk for 3"/24hrs from the high-res ensembles is from near St.
    Louis, MO northward through southern WI, which is also where there
    are notable probabilities for 5"/24 hrs (30-60%), especially near
    the Quad Cities of IA. This is also where the CSU First-Guess ERO
    field is most aggressive, so despite some dryness in the antecedent
    soils, an elevated SLGT risk is warranted for this region.
    Otherwise, cosmetic adjustments were made to both the SLGT and MRGL
    risks across the region.

    ...Upper Peninsula of Michigan...
    The impressive system moving through the Upper Midwest will result
    in increased deformation between 700-500mb pivoting into the Upper
    Peninsula this aftn/eve. This will encourage enhanced ascent across
    the region, despite a slow wane in MUCAPE noted via the various
    models. The accompanying ascent within this persistent deformation
    axis will support widespread showers and thunderstorms today, which
    despite the waning instability will be fueled by PWs as high as
    1.5 inches, or above the 90th climatological percentile. This will
    support rainfall rates that are progged by both HREF and REFS
    neighborhood probabilities to have a 30-60% chance of exceeding
    1"/hr, which will occur within aligned Corfidi vectors/mean 0-6km
    winds to support training.

    3-hr FFG across the area is generally 1.5 to 2.5 inches which has
    20-40% chance of exceedance. This suggests at least scattered
    instances of flash flooding are possible, but will be most likely
    where any more prolonged training can result in 3 inches (50-60%
    chance) to as much as 5 inches (10-20% chance) of rain. After
    coordination with WFO MQT, a SLGT risk was added for the increased
    excessive rainfall potential today and tonight.

    ...Northern Florida through the Central Gulf Coast...
    Robust late-July thermodynamics characterized by PWs of 2-2.25
    inches and MUCAPE above 2000 J/kg will spread across the area today
    and tonight ahead of a quasi-stationary front. This will likely
    result in two periods of convection capable of producing heavy
    rainfall.

    The first will be during peak heating when airmass
    thunderstorms will develop, aided by a modest vorticity impulse
    digging into MS/AL around the large mid-level ridge to the west.
    Weak shear (less than 20 kts) during this time suggests storms that
    develop will be generally of the pulse variety with limited
    organization and lifespans, but storm mergers, boundary
    collisions, and any locally enhanced ascent in the vicinity of this
    shortwave could increase the overage and intensity of storms during
    the aftn/eve.

    These storms should wane with convective overturning during the
    evening, but a secondary signal has shown up in the guidance for
    late tonight into early Saturday, especially across the Florida
    Panhandle and into the Big Bend area. Here, the aforementioned
    shortwave will slow within an area of thickness diffluence, leading
    to a longer period of enhanced synoptic lift aided by modest jet-
    level diffluence. This ascent acting upon any residual boundaries
    and the land breeze could reignite thunderstorms as the LLJ
    attempts to back subtly more to the WSW from W as the front
    approaches, drawing even more impressive PWs along the coast.
    During this time, Corfidi vectors are progged to collapse to 5 kts
    or less and become increasingly anti-parallel to the mean wind
    suggesting some greater backbuilding/training potential with rain
    rates potentially reaching 3"/hr (10-20% chance). Both the HREF and
    REFS indicate a 20-40% chance for 5" of rainfall from this
    nocturnal event, but the deterministic models are quite different
    in the coverage and placement. At this time, after coordination
    with WFO TAE, the MRGL risk was left unchanged for this area, but
    an upgrade to a targeted SLGT risk may be needed with later
    updates, with the SLGT potentially extending (or being more needed)
    through D2.

    ...Four Corners States into the Southern-Central High Plains...
    The monsoon ridge will get suppressed to the south and west in
    response to the potent system moving through the Plains/Midwest,
    with a secondary piece of vorticity energy dropping across the
    southern High Plains into the Texas Panhandle. This will help push
    a cold front through the Southern Plains and bank against the
    terrain of New Mexico later this evening. The overlapping ascent
    from the cold front and shortwave will act upon favorable
    thermodynamics as a ribbon of PWs above 1.5 inches and pooled
    MUCAPE of 1000-1500 J/kg get drawn westward ahead of the front.

    Coverage of monsoonal thunderstorms may be somewhat less than
    previous days today due to the re-centereing of the ridge. But at
    least scattered diurnal thunderstorms are expected from eastern AZ,
    through NM, and into eastern CO with hourly rainfall up to 1 inch
    at times. The focus for heaviest rain is likely where the
    shortwave/front move into NM/TX Panhandle where some organized
    clusters and better training potential exists. This is reflected by
    both HREF and REFS exceedance probabilities reaching 15-25% (FFG)
    and 30-50% (3"/24hrs). This still supports the inherited MRGL risk,
    and only cosmetic adjustments were made based on the new guidance.

    Weiss/Miller


    Day 2
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE THE UPPER
    MIDWEST TO THE GULF COAST AND THE SOUTHERN HIGH PLAINS...

    ...Upper Midwest...

    A potent and unseasonably deep low pressure system (ensemble mean
    forecast MSLP values below the minimum CFSR climatological) will
    continue to pivot across the Upper Midwest as its parent mid/upper
    low digs and deepens over the region. Ahead of the system, strong
    low-level south and southwesterly flow will advect deep Gulf
    moisture (PWs 2-2.25 inches/150-175% of normal) northward. Combined
    with impressive dynamics, large scale ascent, and sufficient
    instability, the threat of convectively driven heavy rain is
    expected to continue into Day 2/Saturday, especially within the
    pivoting comma head due north of the low track across parts of
    Illinois and Indiana. There, the 12Z HREF/RRFS guidance is
    highlighting the potential for significant QPF, with notable
    probabilities of exceeding 3"/24 hrs (60-80%) and 5"/24 hrs
    (25-50%). As a result, the existing SLGT risk can be considered an
    enhanced SLGT from east-central Illinois to northwest Indiana.
    Elsewhere across the Ohio and Tennessee Valleys, only cosmetic
    adjustments were made to the SLGT and MRGL risks.

    ...Parts of the Southeast to the Gulf Coast...

    A mid/upper impulse embedded within northwesterly flow on the
    southern periphery of the deepening low over the Upper Midwest will
    dive into the Southeast before slowing down near the Florida
    Panhandle during the Day on Saturday. Anomalously high PWs of
    2.25-2.75 inches (125-150% of normal) along with 1000-2000+ J/kg of
    MUCAPE will support numerous clusters of slow-moving showers and
    thunderstorms containing intense rainfall rates. The 12Z HREF/RRFS
    show fairly widespread probabilities of 40-90% for QPF greater than
    3"/24 hours and 20-60% for greater than 5"/24 hours across parts
    of the Southeast, especially for portions of Georgia and the
    Florida Panhandle. Given this increased signal for potentially
    significant rainfall, the SLGT risk was expanded southward to
    include southwest Alabama, southern Georgia, and most of the
    Florida Panhandle.

    ...Southern Rockies/High Plains to the Texas Hill Country...

    Monsoonal moisture and instability interacting with upslope flow
    and a southward progressing cold front will support scattered
    showers and thunderstorms from the southern Rockies and High Plains
    to the Texas Hill Country on Day 2/Saturday. This activity will
    have the potential to produce heavy rainfall rates in excess of 1"
    per hour, leading to isolated and scattered instances of flash
    flooding. 12Z HREF/RRFS probabilities for QPF greater than 3"/24
    hours are 20-50% and mostly concentrated across the southern High
    Plains of New Mexico. The existing SLGT risk covering that area
    looked on track so minimal changes were made. However, the
    HREF/RRFS is also beginning to highlight the Texas Hill Country
    with a 10-40% chance for QPF greater than 3"/24 hours. Also notable
    are the very low but non-zero probabilities for greater than 5"/24
    hrs (5-10%). As a result, the MRGL risk was expanded eastward from
    far western Texas with this update, and a future upgrade to a SLGT
    risk can't be ruled out.

    Miller


    Day 3
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, AND OVER PORTIONS OF THE NORTHEAST...

    ...Gulf Coast into the Southeast...
    Long duration onshore flow event from the Gulf continues into D3
    bringing heavy rain to the Big Bend area of Florida and portions of
    the Southeast.

    A potent closed mid-level low centered over Indiana Sunday morning
    will rotate E/SE through D3 bringing height falls to the Gulf
    Coast, and keeping pronounced S/SW flow downstream. As this closed
    low elongated to become at least subtly more N-S oriented, onshore
    flow from the Gulf will locally back and intensify, drawing robust thermodynamics northward into Florida/Georgia. An impressive plume
    of PWs above 2.25" overlapped with MUCAPE of around 2000 J/kg will
    be pooled ahead of the approaching surface cold front, and it is
    this impressive environment that will shift northeast through D3.
    Within this setup, widespread thunderstorms are likely, and with
    mean 0-6km winds aligned parallel to the front onshore, and anti-
    parallel to the Corfidi vectors, the setup appears to suggest a
    high threat for backbuilding and training convection with heavy
    rainfall rates of 2"/hr or more. This will result in locally more
    than 3" of rainfall (SREF/GEFS/ECENS probabilities for 3"/24 hrs as
    high as 10%) falling atop saturated soils from anticipated heavy
    rain on D2. For this reason a SLGT was added near the Florida Big
    Bend region, with the MRGL expanded northeast from inherited.

    ...Upper Midwest to Northeast and Mid-Atlantic region...
    The anomalous mid-level low will continue to track slowly eastward
    from the Midwest into the Ohio Valley on Sunday and Sunday night.
    Beneath this upper low, an occluded surface cyclone will track
    eastward in tandem, with the accompanying fronts producing locally
    enhanced ascent within their vicinity due to overrunning and/or
    convergence. As the wave pushes east, impressive thermodynamic
    advection within the warm sector will surge northward as 30-40 kts
    of wind at 850mb transport PWs of 1.75 to 2.0 inches all the way to
    the Canadian Border overlapping 500-1000 J/kg of MUCAPE. This will
    support widespread thunderstorms with rainfall rates of 1-2"/hr,
    with organization into clusters fostered via 30-35 kts of bulk
    shear.

    Within this warm sector, propagation vectors and mean 0-6km winds
    will become increasingly parallel and aligned to the approaching
    front, which suggests an increasing training threat from the Mid-
    Atlantic states northward into Upstate NY. The guidance has trended
    upward in QPF for this area, and an upgrade to a SLGT risk in parts
    of this area may be needed with later issuances. However, the
    current SLGT risk is focused from eastern lower Michigan northeast
    towards the Adirondacks where an impressive deformation axis will
    develop and lay beneath a rare August-TROWAL to enhance both ascent
    and instability. Here, mean winds become anti-parallel to the
    propagation vectors, and it is likely that some slow
    moving/backbuilding cells will bring heavy rainfall to areas
    including Detroit, Cleveland, and Buffalo on D3. This is where the
    greatest excessive rainfall risk exists, and the inherited SLGT
    risk was modified to account for recent guidance and highest
    (albeit still modest) probabilities for rainfall exceeding
    3"/24hrs.

    ...Southwest...
    The mid-level ridge responsible for the monsoon will remain
    somewhat flattened Sunday into Monday /D3/ but begin to expand
    eastward once again as the downstream trough advects east into the
    Mid-Atlantic states. This will keep much of the favorable
    instability and moisture suppressed to the southern edge of the
    typical monsoon region, with both anomalous PWs and SBCAPE above
    1000 J/kg confined to generally the Mogollon Rim and points south.
    Convection is still likely to blossom across AZ/NM, and storms that
    develop may organize slightly within 25 kts of bulk shear to move
    SW off the terrain at 10-15 kts. However, the coverage and speed of
    convection should limit excessive rainfall potential to be
    isolated, so the MRGL risk was maintained with only subtle cosmetic adjustments.

    Weiss


    Day 4 and Day 5

    Valid 12Z Mon Aug 03 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    ...Portions of the East/Great Lakes/OH Valley...
    The well-defined upper level trough moving through the Ohio Valley
    will begin to fracture on Thursday. There is agreement that an
    axis of anomalous PW values, 2+ standard deviations above the mean,
    2 to 2.25" PW values, will stretch from North Florida,
    northeastward across the coastal Southeast, Mid- Atlantic and from
    eastern NY State into New England. Generally favorable right
    entrance region jet dynamics will accentuate lift in this anomalous
    PW axis, supporting potential for locally heavy rainfall totals. A
    slight risk remains over portions of the northern Mid-Atlantic
    (including portions of NY) into southwest New England where recent
    heavy rains have lowered FFG values/saturated soils.

    The closed low over the Upper OH Valley will become nearly
    stationary on Friday. An area of anomalous PW values will remain
    to the east of this closed low, across the Upper OH Valley into the
    Mid- Atlantic, Southern New England and south into the coastal
    southern Mid-Atlantic. A broad marginal risk area was depicted in
    this anomalous PW axis for locally heavy rains and isolated runoff
    issues. The surface front moving through New England Thursday may
    become stationary and west to east oriented across southern New
    England into the northern Mid-Atlantic Friday. A few models are
    showing more defined heavy rains in the vicinity of this front
    where there is potential for persistent south southwesterly inflow.
    Still a lot of spread with qpf details, warranting only a marginal
    risk at this time, with changes possible with future updates.

    ...Southwest/Southern High Plains...
    For Thursday and Friday, a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.

    ...Portions of the Central/Northern Plains & Midwest...
    A surface front expected to push southeastward from the Upper MS
    Valley into the Upper Lakes and south through the Central Plains.
    On Thursday, there is a decent model signal for 1-2" of rain which
    could fall in a short period of time, so added a Marginal Risk area
    for portions of the Dakotas and northern MN -- it would not be a
    surprise if the guidance trended upward on amounts. For Friday, a
    model consensus exists for an axis of potentially heavy rains from
    Nebraska, eastward into Iowa and southern MN where the front may
    become more west to east oriented. Moist southerly low level
    inflow into the front at this time may support organized
    convection, heavy rains and isolated runoff issues.

    Roth/Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8uO9ta3lAwxMcaAYPPmQbf-_q-aRQ7PNF1IKIwdEnsMyipbUWnK-Fcmz84GqTTdlHDvKC2OfNwHn3Y2DzK31HBOyiY4$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8uO9ta3lAwxMcaAYPPmQbf-_q-aRQ7PNF1IKIwdEnsMyipbUWnK-Fcmz84GqTTdlHDvKC2OfNwHn3Y2DzK31-iCu7CM$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8uO9ta3lAwxMcaAYPPmQbf-_q-aRQ7PNF1IKIwdEnsMyipbUWnK-Fcmz84GqTTdlHDvKC2OfNwHn3Y2DzK311KQz9XE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 1 00:47:20 2026
    FOUS30 KWBC 010045
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    845 PM EDT Fri Jul 31 2026

    Day 1
    Valid 01Z Sat Aug 01 2026 - 12Z Sat Aug 01 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MIDWEST & UPPER PENINSULA OF MICHIGAN...

    ...Central US system...
    An extremely anomalous mid- level low exists for late July across
    IA. An impressively deep system overlapping late July thermodynamics
    is a clear indicator of excessive rainfall potential. Near the
    occluded cyclone in IA (and farther downstream warm sector) PWs
    range from 1.75 to 2.00 inches, with ML CAPE of 500-3000 J/kg at
    the writing of this discussion. Effective bulk shear of 25-35 kts
    should continue convective organization. This environment supports
    hourly rain amounts to 2.5", with the 18z HREF/12z REFS supporting
    additional local totals to 5" this evening/tonight. The three
    hourly flash flood guidance values have lowered due to earlier
    rainfall. Overall, the risk levels from continuity appear
    reasonable but areas were reshaped based on recent convective
    evolution and the 18z HREF/12z REFS guidance.


    ...Upper Peninsula of Michigan...
    Increased deformation between 700-500mb pivoting into the Upper
    Peninsula this aftn/eve along with lake breeze circulations have
    led to convection across eastern portion of the UP of MI. PWs are
    as high as 1.8 inches. Along with ML CAPE of 500+ J/kg, hourly rain
    amounts up to 2.5" remain possible in the short term. This would
    exceed the 3-hr FFG, suggesting at least scattered instances of
    flash flooding are possible. The Slight Risk remains intact to deal
    with convective development here over the next several hours.


    ...Northern Florida through the Central Gulf Coast...
    Robust late-July thermodynamics characterized by PWs of 2-2.25
    inches and MUCAPE above 2000 J/kg will spread across the area today
    and tonight ahead of a quasi-stationary front. Afternoon and
    evening thunderstorms are presently on the wane, but a secondary
    signal exists early Saturday morning, especially across the
    Florida Panhandle and into the Big Bend area. A slow moving
    shortwave moving within an area of thickness diffluence leads to a
    longer period of enhanced synoptic lift aided by modest jet- level
    diffluence. Low-level inflow backs subtly more to the WSW from W
    as the front approaches, drawing even more impressive PWs along the
    coast and instability from the Gulf. During this time, Corfidi
    vectors are progged to collapse to 5 kts or less and become
    increasingly anti- parallel to the mean wind suggesting some
    greater backbuilding/training potential with rain rates potentially
    reaching 3"/hr if everything aligns perfectly prior to 12z. The
    18z HREF/12z REFS indicate the potential for local 2-4" by 12z,
    with the HREF less bullish. Left the Marginal Risk intact but
    Slight Risk impacts can't be ruled out.


    ...Southern-Central High Plains...
    The monsoon ridge gets suppressed to the south and west in
    response to the potent system moving through the Plains/Midwest,
    with a secondary piece of vorticity energy dropping across the
    southern High Plains into the Texas Panhandle. This will help push
    a cold front through the Southern Plains and bank against the
    terrain of New Mexico later this evening. The overlapping ascent
    from the cold front and shortwave will act upon favorable
    thermodynamics as a ribbon of PWs above 1.5 inches and pooled
    MUCAPE of 1000-1500 J/kg get drawn westward ahead of the front.
    Radar reflectivity trends show some clustering of thunderstorms in
    eastern NM which could merge into preceding activity across
    northwest TX in the short term. Activity should be on the wane
    midnight or so. Left the Marginal Risk level but resculpted the
    area to reflect recent radar reflectivity and 18z HREF/12z REFS
    guidance.

    Roth


    Day 2
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE THE UPPER
    MIDWEST TO THE GULF COAST AND THE SOUTHERN HIGH PLAINS...

    ...Upper Midwest...
    A potent and unseasonably deep low pressure system (ensemble mean
    forecast MSLP values below the minimum CFSR climatological) will
    continue to pivot across the Upper Midwest as its parent mid/upper
    low digs and deepens over the region. Ahead of the system, strong
    low-level south and southwesterly flow will advect deep Gulf
    moisture (PWs 2-2.25 inches/150-175% of normal) northward. Combined
    with impressive dynamics, large scale ascent, and sufficient
    instability, the threat of convectively driven heavy rain is
    expected to continue into Day 2/Saturday, especially within the
    pivoting comma head due north of the low track across parts of
    Illinois and Indiana. There, the 12Z HREF/RRFS guidance is
    highlighting the potential for significant QPF, with notable
    probabilities of exceeding 3"/24 hrs (60-80%) and 5"/24 hrs
    (25-50%). As a result, the existing SLGT risk can be considered an
    enhanced SLGT from east-central Illinois to northwest Indiana.
    Elsewhere across the Ohio and Tennessee Valleys, only cosmetic
    adjustments were made to the SLGT and MRGL risks.


    ...Parts of the Southeast to the Gulf Coast...
    A mid/upper impulse embedded within northwesterly flow on the
    southern periphery of the deepening low over the Upper Midwest will
    dive into the Southeast before slowing down near the Florida
    Panhandle during the Day on Saturday. Anomalously high PWs of
    2.25-2.75 inches (125-150% of normal) along with 1000-2000+ J/kg of
    MUCAPE will support numerous clusters of slow-moving showers and
    thunderstorms containing intense rainfall rates. The 12Z HREF/RRFS
    show fairly widespread probabilities of 40-90% for QPF greater than
    3"/24 hours and 20-60% for greater than 5"/24 hours across parts
    of the Southeast, especially for portions of Georgia and the
    Florida Panhandle. Given this increased signal for potentially
    significant rainfall, the SLGT risk was expanded southward to
    include southwest Alabama, southern Georgia, and most of the
    Florida Panhandle.


    ...Southern Rockies/High Plains to the Texas Hill Country...
    Monsoonal moisture and instability interacting with upslope flow
    and a southward progressing cold front will support scattered
    showers and thunderstorms from the southern Rockies and High Plains
    to the Texas Hill Country on Day 2/Saturday. This activity will
    have the potential to produce heavy rainfall rates in excess of 1"
    per hour, leading to isolated and scattered instances of flash
    flooding. 12Z HREF/RRFS probabilities for QPF greater than 3"/24
    hours are 20-50% and mostly concentrated across the southern High
    Plains of New Mexico. The existing SLGT risk covering that area
    looked on track so minimal changes were made. However, the
    HREF/RRFS is also beginning to highlight the Texas Hill Country
    with a 10-40% chance for QPF greater than 3"/24 hours. Also notable
    are the very low but non-zero probabilities for greater than 5"/24
    hrs (5-10%). As a result, the MRGL risk was expanded eastward from
    far western Texas with this update, and a future upgrade to a SLGT
    risk can't be ruled out.

    Miller


    Day 3
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, AND OVER PORTIONS OF THE NORTHEAST...

    ...Gulf Coast into the Southeast...
    Long duration onshore flow event from the Gulf continues into D3
    bringing heavy rain to the Big Bend area of Florida and portions of
    the Southeast.

    A potent closed mid-level low centered over Indiana Sunday morning
    will rotate E/SE through D3 bringing height falls to the Gulf
    Coast, and keeping pronounced S/SW flow downstream. As this closed
    low elongated to become at least subtly more N-S oriented, onshore
    flow from the Gulf will locally back and intensify, drawing robust thermodynamics northward into Florida/Georgia. An impressive plume
    of PWs above 2.25" overlapped with MUCAPE of around 2000 J/kg will
    be pooled ahead of the approaching surface cold front, and it is
    this impressive environment that will shift northeast through D3.
    Within this setup, widespread thunderstorms are likely, and with
    mean 0-6km winds aligned parallel to the front onshore, and anti-
    parallel to the Corfidi vectors, the setup appears to suggest a
    high threat for backbuilding and training convection with heavy
    rainfall rates of 2"/hr or more. This will result in locally more
    than 3" of rainfall (SREF/GEFS/ECENS probabilities for 3"/24 hrs as
    high as 10%) falling atop saturated soils from anticipated heavy
    rain on D2. For this reason a SLGT was added near the Florida Big
    Bend region, with the MRGL expanded northeast from inherited.


    ...Upper Midwest to Northeast and Mid-Atlantic region...
    The anomalous mid-level low will continue to track slowly eastward
    from the Midwest into the Ohio Valley on Sunday and Sunday night.
    Beneath this upper low, an occluded surface cyclone will track
    eastward in tandem, with the accompanying fronts producing locally
    enhanced ascent within their vicinity due to overrunning and/or
    convergence. As the wave pushes east, impressive thermodynamic
    advection within the warm sector will surge northward as 30-40 kts
    of wind at 850mb transport PWs of 1.75 to 2.0 inches all the way to
    the Canadian Border overlapping 500-1000 J/kg of MUCAPE. This will
    support widespread thunderstorms with rainfall rates of 1-2"/hr,
    with organization into clusters fostered via 30-35 kts of bulk
    shear.

    Within this warm sector, propagation vectors and mean 0-6km winds
    will become increasingly parallel and aligned to the approaching
    front, which suggests an increasing training threat from the Mid-
    Atlantic states northward into Upstate NY. The guidance has trended
    upward in QPF for this area, and an upgrade to a SLGT risk in parts
    of this area may be needed with later issuances. However, the
    current SLGT risk is focused from eastern lower Michigan northeast
    towards the Adirondacks where an impressive deformation axis will
    develop and lay beneath a rare August-TROWAL to enhance both ascent
    and instability. Here, mean winds become anti-parallel to the
    propagation vectors, and it is likely that some slow
    moving/backbuilding cells will bring heavy rainfall to areas
    including Detroit, Cleveland, and Buffalo on D3. This is where the
    greatest excessive rainfall risk exists, and the inherited SLGT
    risk was modified to account for recent guidance and highest
    (albeit still modest) probabilities for rainfall exceeding
    3"/24hrs.


    ...Southwest...
    The mid-level ridge responsible for the monsoon will remain
    somewhat flattened Sunday into Monday /D3/ but begin to expand
    eastward once again as the downstream trough advects east into the
    Mid-Atlantic states. This will keep much of the favorable
    instability and moisture suppressed to the southern edge of the
    typical monsoon region, with both anomalous PWs and SBCAPE above
    1000 J/kg confined to generally the Mogollon Rim and points south.
    Convection is still likely to blossom across AZ/NM, and storms that
    develop may organize slightly within 25 kts of bulk shear to move
    SW off the terrain at 10-15 kts. However, the coverage and speed of
    convection should limit excessive rainfall potential to be
    isolated, so the MRGL risk was maintained with only subtle cosmetic adjustments.

    Weiss


    Day 4 and Day 5

    Valid 12Z Mon Aug 03 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    ...Portions of the East/Great Lakes/OH Valley...
    The well-defined upper level trough moving through the Ohio Valley
    will begin to fracture on Thursday. There is agreement that an
    axis of anomalous PW values, 2+ standard deviations above the mean,
    2 to 2.25" PW values, will stretch from North Florida,
    northeastward across the coastal Southeast, Mid- Atlantic and from
    eastern NY State into New England. Generally favorable right
    entrance region jet dynamics will accentuate lift in this anomalous
    PW axis, supporting potential for locally heavy rainfall totals. A
    slight risk remains over portions of the northern Mid-Atlantic
    (including portions of NY) into southwest New England where recent
    heavy rains have lowered FFG values/saturated soils.

    The closed low over the Upper OH Valley will become nearly
    stationary on Friday. An area of anomalous PW values will remain
    to the east of this closed low, across the Upper OH Valley into the
    Mid- Atlantic, Southern New England and south into the coastal
    southern Mid-Atlantic. A broad marginal risk area was depicted in
    this anomalous PW axis for locally heavy rains and isolated runoff
    issues. The surface front moving through New England Thursday may
    become stationary and west to east oriented across southern New
    England into the northern Mid-Atlantic Friday. A few models are
    showing more defined heavy rains in the vicinity of this front
    where there is potential for persistent south southwesterly inflow.
    Still a lot of spread with qpf details, warranting only a marginal
    risk at this time, with changes possible with future updates.


    ...Southwest/Southern High Plains...
    For Thursday and Friday, a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.


    ...Portions of the Central/Northern Plains & Midwest...
    A surface front expected to push southeastward from the Upper MS
    Valley into the Upper Lakes and south through the Central Plains.
    On Thursday, there is a decent model signal for 1-2" of rain which
    could fall in a short period of time, so added a Marginal Risk area
    for portions of the Dakotas and northern MN -- it would not be a
    surprise if the guidance trended upward on amounts. For Friday, a
    model consensus exists for an axis of potentially heavy rains from
    Nebraska, eastward into Iowa and southern MN where the front may
    become more west to east oriented. Moist southerly low level
    inflow into the front at this time may support organized
    convection, heavy rains and isolated runoff issues.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_0AgoXurlre95Uea792Zf1dIxaFMaZlVqlpsMl-sbkXEYBJXL4J5kV8rMsN0VP1VB6lAmb5IJ2y9FgFco-fWCSVF3iI$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_0AgoXurlre95Uea792Zf1dIxaFMaZlVqlpsMl-sbkXEYBJXL4J5kV8rMsN0VP1VB6lAmb5IJ2y9FgFco-fWWgOp7ak$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_0AgoXurlre95Uea792Zf1dIxaFMaZlVqlpsMl-sbkXEYBJXL4J5kV8rMsN0VP1VB6lAmb5IJ2y9FgFco-fWEr2nu8M$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 1 08:36:22 2026
    FOUS30 KWBC 010835
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    435 AM EDT Sat Aug 1 2026

    Day 1
    Valid 12Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE UPPER
    MIDWEST TO THE GULF COAST AND FOR NEW MEXICO INTO THE SOUTHERN
    HIGH PLAINS...

    ...Upper Midwest...

    A potent and unseasonably deep low pressure system will continue tracking across the Upper Midwest as its parent mid/upper low digs and
    deepens over the region. A steady influx of deep Gulf moisture will
    be pooling ahead of the system with PW values around 2-2.25
    inches/150-175% of normal. Strong forcing, large scale ascent,
    and sufficient instability will all be present to lead to
    efficient,heavy rainfall especially within the pivoting comma head
    due north of the low track across parts of Illinois and Indiana
    where guidance has been suggesting a concentration of 3 to 5
    inches. As a result, the existing Slight Risk spans the Midwest to
    the Tennessee Valley and the portion over east-central Illinois to
    northern Indiana can be considered an enhanced Slight.

    ...Parts of the Southeast to the Gulf Coast...

    A mid/upper impulse embedded within northwesterly flow on the
    southern periphery of the deepening low over the Upper Midwest will
    dive into the Southeast before slowing down near the Florida
    Panhandle during the Day. Anomalously high PW values of 2.25-2.75
    inches (125-150% of normal) along with 1000-2000+ J/kg of MUCAPE
    will support numerous clusters of slow-moving showers and
    thunderstorms containing intense rainfall rates. Some of the hi-res
    guidance is favoring parts of Georgia and Florida for very
    localized pockets of 3+ inches (very isolated areas of 5+ inches).
    A Slight Risk covers much of the Florida Panhandle, eastern
    Alabama, most of Georgia, western half of South Carolina, and western
    North Carolina.

    ...Southern Rockies/High Plains to the Texas Hill Country...

    Monsoonal moisture and instability interacting with upslope flow
    and a southward progressing cold front will support scattered
    showers and thunderstorms from the Southern Rockies and High
    Plains to the Texas Hill Country. Individual storms could
    potentially drop 1+ inch/hr rainfall rates that may lead to
    isolated to scattered instances of flash flooding. The most
    favorable locations for this will be across eastern New Mexico
    into far western portions of Texas. A Slight Risk area remains in
    effect for this part of the region. There continues to be an
    increasing signal for multiple inches of rainfall to focus across
    the Hill Country. A broad Marginal Risk spans from southeast
    Arizona northward to southern Colorado and to the east of the Texas
    Hill Country.

    Campbell/Miller


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, AND OVER PORTIONS OF THE NORTHEAST...

    ...Gulf Coast into the Southeast...

    Onshore flow will continue to focus heavy rainfall over northern
    Florida and parts of the Southeast. The mid-level low over Indiana
    is forecast to move east/south allowing for height falls to reach
    the Gulf Coast and maintaining S/SW flow downstream. An impressive
    plume of PWs above 2.25" overlapped with MUCAPE of around 2000
    J/kg will be pooled ahead of the approaching surface cold front,
    and it is this impressive environment that will shift northeast

    Thunderstorms will be widespread; training and backbuilding can be
    expected with hourly rates reaching 2 or more inches/hour. Several
    locations may accumulate 3+ inches/24 hours thus maintaining an
    elevated threat for flash flooding.

    ...Upper Midwest to Northeast and Mid-Atlantic region...

    A slow moving occluded front will be advancing eastward into the
    Ohio Valley. Impressive thermodynamic advection within the warm
    sector will surge northward as 30-40 kts of wind at 850mb transport
    PW values of 1.75 to 2.0 inches all the way to the Canadian Border
    overlapping 500-1000 J/kg of MUCAPE. This will support widespread
    thunderstorms with rainfall rates of 1-2"/hr, with organization
    into clusters fostered via 30-35 kts of bulk shear.

    With time, winds will become more parallel to the front which will
    increase the threat for training of cells from the Mid-Atlantic
    states northward into Upstate New York. The current Slight Risk is
    focused from eastern lower Michigan northeast towards the
    Adirondacks where an impressive deformation axis will develop and
    lay beneath a rare August-TROWAL to enhance both ascent and
    instability. Here, mean winds become anti-parallel to the
    propagation vectors, and it is likely that some slow
    moving/backbuilding cells will bring heavy rainfall to areas
    including Detroit, Cleveland, and Buffalo. This is where the
    greatest excessive rainfall risk exists and where the highest
    probabilities for rainfall exceeding 3"/24hrs.

    ...Southwest...

    Favorable instability and moisture will be a bit suppressed during
    this period thanks to the with the somewhat flattened ridge
    downstream. The anomalous PW values and SBCAPE above 1000 J/kg will
    generally be confined to the Mogollon Rim and southern vicinity.
    Convection is still likely to blossom across Arizona and New Mexico
    and storms that develop may organize slightly to move southwest
    off the terrain. A Marginal Risk area remains in effect for this
    period.

    Campbell/Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID-ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    ...Portions of the East Coast and Ohio Valley...

    An axis of anomalous PW values, 2+ standard deviations above the
    mean, 2 to 2.25" PW values, will stretch from North Florida,
    northeastward across the coastal Southeast, Mid- Atlantic and from
    eastern New York State into New England will support locally heavy
    rainfall. A slight risk remains over portions of the northern Mid-
    Atlantic (including portions of NY) into southwest New England
    where recent heavy rains have lowered FFG values/saturated soils.

    During the day the closed low is forecast to slow/stall while
    maintaining an area of anomalous PW values east of this closed
    low, across the Upper Ohio Valley into the Mid- Atlantic, Southern
    New England and south into the coastal southern Mid-Atlantic. A
    broad marginal risk area was depicted in this anomalous PW axis for
    locally heavy rains and isolated runoff issues.

    ...Southwest/Southern High Plains...

    Convection will become less suppressed as the ridge builds to the
    east allowing for more monsoonal moisture and instability to reach
    the Southern Rockies/adjacent High Plains. Locally heavy rainfall
    with isolated runoff issues possible for this period. A Marginal
    Risk spans from southeast Arizona into New Mexico and south-
    central Colorado.

    ...Portions of the Central/Northern Plains and Midwest...

    Areal average of 1-2 inches expected as a surface front advances
    southeastward from the Upper Mississippi Valley into the Upper
    Lakes and south through the Central Plains. Moist southerly low
    level inflow into the front at this time may support organized
    convection, heavy rains and isolated runoff issues. A Marginal Risk
    is in affect for northern Minnesota, easter North Dakota and
    northeast South Dakota.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Tue Aug 04 2026 - 12Z Thu Aug 06 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FROM THE UPPER
    OHIO VALLEY/EASTERN LAKES INTO THE NORTHEAST, FROM THE CENTRAL
    PLAINS IN THE MID TO UPPER MISSISSIPPI VALLEY AND OVER THE
    SOUTHWEST...

    ...Upper OH Valley, Central Appalachians, Lower Lakes, Mid-Atlantic
    into the Northeast...

    Very little movement expected day 4 to the closed low in the
    vicinity of eastern KY/eastern TN, with then a northeastward push
    into the eastern lakes on Wednesday as it begins to weaken. A broad
    region of anomalous PW values will persist day 4 and day 5 to the
    east of this closed low from the Upper OH Valley, Central
    Appalachians, eastward into the Mid- Atlantic, much of NY State and
    southern New England. Confidence is low with qpf details, but
    there will likely be areas of heavy rains both day 4 and 5 across
    these areas with isolated runoff issues possible. Given the
    uncertainties with details, the risk level was kept at marginal for
    both day 4 and 5.

    ...Southwest/Southern High Plains...
    For both day 4 and 5, 1200 UTC Tuesday to 1200 UTC Thursday, a
    marginal risk was depicted for monsoonal convection across southern
    Arizona into New Mexico. Not a lot of confidence with qpf details
    here, but locally heavy rains and isolated runoff issues possible
    in the above average PW values expected across this area.

    ...Central Plains into the Mid to Upper MS Valley...

    A surface frontal boundary is expected to remain nearly stationary
    during the day 4 and day 5 time period from the Central Plains, east-northeastward into the Mid to Upper MS Valley region. This
    front will be situated along the southern edge of the westerlies
    where shortwave energy pushing east northeastward along the frontal
    zone will support potential for organized convection both day 4 and
    day 5. PW values expected to be slightly above average...1.5 to
    1.75"+ in the vicinity of this front, supporting heavy precip
    totals where convection does organize and isolated runoff issues.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!5Y8o1rAqsn2gIRW9rzzor7Xw-gDz8JY-I0eF0Rv2CSyc_R9M4uOk89Q2cxYnvDMkVUATd0IpqPNt70rRTeW4UEdUCjI$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!5Y8o1rAqsn2gIRW9rzzor7Xw-gDz8JY-I0eF0Rv2CSyc_R9M4uOk89Q2cxYnvDMkVUATd0IpqPNt70rRTeW4fRFPK2c$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!5Y8o1rAqsn2gIRW9rzzor7Xw-gDz8JY-I0eF0Rv2CSyc_R9M4uOk89Q2cxYnvDMkVUATd0IpqPNt70rRTeW4ca8HEkE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 1 15:57:18 2026
    FOUS30 KWBC 011556
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1156 AM EDT Sat Aug 1 2026

    Day 1
    Valid 16Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE UPPER
    MIDWEST TO THE GULF COAST AND FOR NEW MEXICO INTO THE SOUTHERN
    HIGH PLAINS...

    ...Upper Midwest to the Gulf Coast...
    An anomalously strong upper low (NAEFS 500mb heights falling below
    the 2.5 percentile, 850mb heights to below the climo minimum) will
    pivot slowly eastward today, reaching central Indiana by the end
    of the forecast period. This closed low will drive pronounced
    height falls and mid-level divergence for ascent across the area,
    while the accompanying occluded surface low and trailing cold front
    push into the Ohio and Tennessee Valleys. Downstream of these
    features, robust thermodynamics will be drawn northward from the
    Gulf, resulting in a corridor of MUCAPE above 1000 J/kg overlapped
    with PWs of 1.75 to 2.00 inches extending from the Florida
    Panhandle all the way into Indiana.

    Within this broad plume of impressive thermodynamics, all convection
    which develops ahead of the system will have the potential to
    produce excessive rain rates. This is supported by both HREF and
    REFS neighborhood probabilities that indicate a 30-70% chance of
    at least 1"/hr rates within a broad area where thunderstorms are
    expected today. With mean 0-6km winds aligned to the front,
    especially from Florida through Kentucky, at least short duration
    training is expected, and this results in notable spatial coverage
    of probabilities above 40% (almost continuous) for at least 3" of
    rainfall today from Florida to Illinois. Some of this will be
    moving across vulnerable soils due to natural sensitivity of
    terrain features or from recent heavy rains, but within this
    broader area there are two focused regions with a slightly higher
    threat today for flash flooding.

    1) Illinois into Indiana: Here, an impressive deformation axis will
    setup N/NW of the mid-level low as it pivots E/SE, and will drive
    ascent into an impressive (especially for August 1) TROWAL as the
    accompanying theta-e ridge pivots cyclonically around the system.
    This will result not only as a region of increased instability and
    moisture, but also a greater training risk as propagation vectors
    and mean winds become increasingly anti-parallel. This suggests a
    high threat for backbuilding and repeating cells, through which the
    1-2"/hr rain rates could cause locally more than 5" of rain (30-50%
    chance). Although the SBCAPE may be somewhat muted here, the
    elevated CAPE should offset that limitation, and an enhanced slight
    risk continues with only modest cosmetic adjustments.

    2) Florida Gulf Coast and Panhandle: Impressive thermodynamics
    acted upon by a notable shortwave digging across Alabama will spawn
    multiple rounds of thunderstorms today producing rainfall rates as
    much as 3"/hr. Storms will likely develop over the Gulf through
    today and then train to the E/NE moving shore the central/eastern
    Florida Panhandle before lifting northeast into southern Georgia.
    The cold front slowly approaching from the NW will additionally
    contribute ascent and increase shear, so organization into clusters
    is likely, and this could result in 5+" of rain, with locally up to
    8" possible (10-20% chance). Although there is some uncertainty in
    placement of the heaviest rain among the various deterministic
    models, both the HREF and REFS have the greatest signal from the
    Emerald Coast through the Nature Coast, and then just inland.
    Although there is consistency in this ensemble signal, the
    variability in the guidance across a region that has some of the
    highest FFG in the country, suggests the current SLGT risk remains
    the correct level for this event, but after coordination with WFO
    TAE a targeted enhanced slight was added where heavy rain is
    ongoing and both the REFS and HREF focus the greatest 24-hr rain
    probabilities.

    ...Southern Rockies/High Plains to the Texas Hill Country...
    Monsoon ridge gets suppressed to the SW even further today as the
    anomalous closed low and longwave trough dig across the
    Mississippi Valley. This re-structuring of the ridge will squelch a
    lot of monsoon activity today, but weak shortwaves rotating around
    the ridge and south/southeast into NM/AZ will provide sufficient
    ascent for convection this aftn/eve. At the same time, a cold front
    dropping through the middle of the country will bank into the High
    Plains of NM, providing an additional focus for ascent through
    accompanying upslope flow. Together, this will create scattered to
    widespread thunderstorms for eastern NM.

    This activity will likely begin on higher terrain, typical, but
    increased effective bulk shear (30-40 kts by this aftn) will help
    organized cells into clusters which will then drop steadily
    southward on mean 0-6km winds of 10-15 kts. Despite the steady
    progression of cells today, hourly rainfall may exceed 1" in places
    (supported by HREF, REFS, and the UA WRF), which could cause
    excessive rainfall leading to flash flooding, especially atop
    vulnerable terrain, burn scars, or urban areas. The greatest
    coverage of activity is expected in eastern NM today where the
    inherited SLGT risk was only cosmetically adjusted.

    The other area of interest is associated with an increasing signal
    for heavy rainfall for portions of West Texas into the Hill
    Country. Thunderstorms developing along the southward sagging cold
    front will tap into robust thermodynamics characterized by PWs of
    1.75 to 2.00 and MUCAPE of 2000 J/kg. This will be most impressive
    in a narrow channel immediately ahead of the cold front, and will
    support heavy rainfall rates of 2"/hr or more. The high-res CAMs
    have become more aggressive with convective coverage today, and
    although cells should move steadily S/SW, any short term training
    through modest shear along the front could produce 2-3" of rain
    with locally higher amounts. Considered an upgrade to a SLGT risk,
    especially noting the continued elevated 0-40cm soil moisture and
    general sensitivity of this region, but after coordination with
    the impacted WFOs, and due to uncertainty in storm coverage, opted
    to maintain the MRGL risk at this time.

    Weiss


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, AND OVER PORTIONS OF THE NORTHEAST...

    ...Gulf Coast into the Southeast...

    Onshore flow will continue to focus heavy rainfall over northern
    Florida and parts of the Southeast. The mid-level low over Indiana
    is forecast to move east/south allowing for height falls to reach
    the Gulf Coast and maintaining S/SW flow downstream. An impressive
    plume of PWs above 2.25" overlapped with MUCAPE of around 2000
    J/kg will be pooled ahead of the approaching surface cold front,
    and it is this impressive environment that will shift northeast

    Thunderstorms will be widespread; training and backbuilding can be
    expected with hourly rates reaching 2 or more inches/hour. Several
    locations may accumulate 3+ inches/24 hours thus maintaining an
    elevated threat for flash flooding.

    ...Upper Midwest to Northeast and Mid-Atlantic region...

    A slow moving occluded front will be advancing eastward into the
    Ohio Valley. Impressive thermodynamic advection within the warm
    sector will surge northward as 30-40 kts of wind at 850mb transport
    PW values of 1.75 to 2.0 inches all the way to the Canadian Border
    overlapping 500-1000 J/kg of MUCAPE. This will support widespread
    thunderstorms with rainfall rates of 1-2"/hr, with organization
    into clusters fostered via 30-35 kts of bulk shear.

    With time, winds will become more parallel to the front which will
    increase the threat for training of cells from the Mid-Atlantic
    states northward into Upstate New York. The current Slight Risk is
    focused from eastern lower Michigan northeast towards the
    Adirondacks where an impressive deformation axis will develop and
    lay beneath a rare August-TROWAL to enhance both ascent and
    instability. Here, mean winds become anti-parallel to the
    propagation vectors, and it is likely that some slow
    moving/backbuilding cells will bring heavy rainfall to areas
    including Detroit, Cleveland, and Buffalo. This is where the
    greatest excessive rainfall risk exists and where the highest
    probabilities for rainfall exceeding 3"/24hrs.

    ...Southwest...

    Favorable instability and moisture will be a bit suppressed during
    this period thanks to the with the somewhat flattened ridge
    downstream. The anomalous PW values and SBCAPE above 1000 J/kg will
    generally be confined to the Mogollon Rim and southern vicinity.
    Convection is still likely to blossom across Arizona and New Mexico
    and storms that develop may organize slightly to move southwest
    off the terrain. A Marginal Risk area remains in effect for this
    period.

    Campbell/Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE NORTHERN
    MID-ATLANTIC INTO SOUTHERN NEW YORK STATE AND SOUTHERN NEW
    ENGLAND...

    ...Portions of the East Coast and Ohio Valley...

    An axis of anomalous PW values, 2+ standard deviations above the
    mean, 2 to 2.25" PW values, will stretch from North Florida,
    northeastward across the coastal Southeast, Mid- Atlantic and from
    eastern New York State into New England will support locally heavy
    rainfall. A slight risk remains over portions of the northern Mid-
    Atlantic (including portions of NY) into southwest New England
    where recent heavy rains have lowered FFG values/saturated soils.

    During the day the closed low is forecast to slow/stall while
    maintaining an area of anomalous PW values east of this closed
    low, across the Upper Ohio Valley into the Mid- Atlantic, Southern
    New England and south into the coastal southern Mid-Atlantic. A
    broad marginal risk area was depicted in this anomalous PW axis for
    locally heavy rains and isolated runoff issues.

    ...Southwest/Southern High Plains...

    Convection will become less suppressed as the ridge builds to the
    east allowing for more monsoonal moisture and instability to reach
    the Southern Rockies/adjacent High Plains. Locally heavy rainfall
    with isolated runoff issues possible for this period. A Marginal
    Risk spans from southeast Arizona into New Mexico and south-
    central Colorado.

    ...Portions of the Central/Northern Plains and Midwest...

    Areal average of 1-2 inches expected as a surface front advances
    southeastward from the Upper Mississippi Valley into the Upper
    Lakes and south through the Central Plains. Moist southerly low
    level inflow into the front at this time may support organized
    convection, heavy rains and isolated runoff issues. A Marginal Risk
    is in affect for northern Minnesota, easter North Dakota and
    northeast South Dakota.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Tue Aug 04 2026 - 12Z Thu Aug 06 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FROM THE UPPER
    OHIO VALLEY/EASTERN LAKES INTO THE NORTHEAST, FROM THE CENTRAL
    PLAINS IN THE MID TO UPPER MISSISSIPPI VALLEY AND OVER THE
    SOUTHWEST...

    ...Upper OH Valley, Central Appalachians, Lower Lakes, Mid-Atlantic
    into the Northeast...

    Very little movement expected day 4 to the closed low in the
    vicinity of eastern KY/eastern TN, with then a northeastward push
    into the eastern lakes on Wednesday as it begins to weaken. A broad
    region of anomalous PW values will persist day 4 and day 5 to the
    east of this closed low from the Upper OH Valley, Central
    Appalachians, eastward into the Mid- Atlantic, much of NY State and
    southern New England. Confidence is low with qpf details, but
    there will likely be areas of heavy rains both day 4 and 5 across
    these areas with isolated runoff issues possible. Given the
    uncertainties with details, the risk level was kept at marginal for
    both day 4 and 5.

    ...Southwest/Southern High Plains...
    For both day 4 and 5, 1200 UTC Tuesday to 1200 UTC Thursday, a
    marginal risk was depicted for monsoonal convection across southern
    Arizona into New Mexico. Not a lot of confidence with qpf details
    here, but locally heavy rains and isolated runoff issues possible
    in the above average PW values expected across this area.

    ...Central Plains into the Mid to Upper MS Valley...

    A surface frontal boundary is expected to remain nearly stationary
    during the day 4 and day 5 time period from the Central Plains, east-northeastward into the Mid to Upper MS Valley region. This
    front will be situated along the southern edge of the westerlies
    where shortwave energy pushing east northeastward along the frontal
    zone will support potential for organized convection both day 4 and
    day 5. PW values expected to be slightly above average...1.5 to
    1.75"+ in the vicinity of this front, supporting heavy precip
    totals where convection does organize and isolated runoff issues.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7Zcccnm4AHYD6xVpdIQmigWoH3vd4QRqEMwgRouYyty7zep8RWEZQlxEHqsfYU4FwFL_xFw0cRFHi0uiC_VK9U8RdSg$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7Zcccnm4AHYD6xVpdIQmigWoH3vd4QRqEMwgRouYyty7zep8RWEZQlxEHqsfYU4FwFL_xFw0cRFHi0uiC_VKOQZvx7A$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7Zcccnm4AHYD6xVpdIQmigWoH3vd4QRqEMwgRouYyty7zep8RWEZQlxEHqsfYU4FwFL_xFw0cRFHi0uiC_VKrZW9n0M$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 1 19:11:30 2026
    FOUS30 KWBC 011911
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    311 PM EDT Sat Aug 1 2026

    Day 1
    Valid 16Z Sat Aug 01 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE UPPER
    MIDWEST TO THE GULF COAST AND FOR NEW MEXICO INTO THE SOUTHERN
    HIGH PLAINS...

    ...Upper Midwest to the Gulf Coast...
    An anomalously strong upper low (NAEFS 500mb heights falling below
    the 2.5 percentile, 850mb heights to below the climo minimum) will
    pivot slowly eastward today, reaching central Indiana by the end
    of the forecast period. This closed low will drive pronounced
    height falls and mid-level divergence for ascent across the area,
    while the accompanying occluded surface low and trailing cold front
    push into the Ohio and Tennessee Valleys. Downstream of these
    features, robust thermodynamics will be drawn northward from the
    Gulf, resulting in a corridor of MUCAPE above 1000 J/kg overlapped
    with PWs of 1.75 to 2.00 inches extending from the Florida
    Panhandle all the way into Indiana.

    Within this broad plume of impressive thermodynamics, all convection
    which develops ahead of the system will have the potential to
    produce excessive rain rates. This is supported by both HREF and
    REFS neighborhood probabilities that indicate a 30-70% chance of
    at least 1"/hr rates within a broad area where thunderstorms are
    expected today. With mean 0-6km winds aligned to the front,
    especially from Florida through Kentucky, at least short duration
    training is expected, and this results in notable spatial coverage
    of probabilities above 40% (almost continuous) for at least 3" of
    rainfall today from Florida to Illinois. Some of this will be
    moving across vulnerable soils due to natural sensitivity of
    terrain features or from recent heavy rains, but within this
    broader area there are two focused regions with a slightly higher
    threat today for flash flooding.

    1) Illinois into Indiana: Here, an impressive deformation axis will
    setup N/NW of the mid-level low as it pivots E/SE, and will drive
    ascent into an impressive (especially for August 1) TROWAL as the
    accompanying theta-e ridge pivots cyclonically around the system.
    This will result not only as a region of increased instability and
    moisture, but also a greater training risk as propagation vectors
    and mean winds become increasingly anti-parallel. This suggests a
    high threat for backbuilding and repeating cells, through which the
    1-2"/hr rain rates could cause locally more than 5" of rain (30-50%
    chance). Although the SBCAPE may be somewhat muted here, the
    elevated CAPE should offset that limitation, and an enhanced slight
    risk continues with only modest cosmetic adjustments.

    2) Florida Gulf Coast and Panhandle: Impressive thermodynamics
    acted upon by a notable shortwave digging across Alabama will spawn
    multiple rounds of thunderstorms today producing rainfall rates as
    much as 3"/hr. Storms will likely develop over the Gulf through
    today and then train to the E/NE moving shore the central/eastern
    Florida Panhandle before lifting northeast into southern Georgia.
    The cold front slowly approaching from the NW will additionally
    contribute ascent and increase shear, so organization into clusters
    is likely, and this could result in 5+" of rain, with locally up to
    8" possible (10-20% chance). Although there is some uncertainty in
    placement of the heaviest rain among the various deterministic
    models, both the HREF and REFS have the greatest signal from the
    Emerald Coast through the Nature Coast, and then just inland.
    Although there is consistency in this ensemble signal, the
    variability in the guidance across a region that has some of the
    highest FFG in the country, suggests the current SLGT risk remains
    the correct level for this event, but after coordination with WFO
    TAE a targeted enhanced slight was added where heavy rain is
    ongoing and both the REFS and HREF focus the greatest 24-hr rain
    probabilities.

    ...Southern Rockies/High Plains to the Texas Hill Country...
    Monsoon ridge gets suppressed to the SW even further today as the
    anomalous closed low and longwave trough dig across the
    Mississippi Valley. This re-structuring of the ridge will squelch a
    lot of monsoon activity today, but weak shortwaves rotating around
    the ridge and south/southeast into NM/AZ will provide sufficient
    ascent for convection this aftn/eve. At the same time, a cold front
    dropping through the middle of the country will bank into the High
    Plains of NM, providing an additional focus for ascent through
    accompanying upslope flow. Together, this will create scattered to
    widespread thunderstorms for eastern NM.

    This activity will likely begin on higher terrain, typical, but
    increased effective bulk shear (30-40 kts by this aftn) will help
    organized cells into clusters which will then drop steadily
    southward on mean 0-6km winds of 10-15 kts. Despite the steady
    progression of cells today, hourly rainfall may exceed 1" in places
    (supported by HREF, REFS, and the UA WRF), which could cause
    excessive rainfall leading to flash flooding, especially atop
    vulnerable terrain, burn scars, or urban areas. The greatest
    coverage of activity is expected in eastern NM today where the
    inherited SLGT risk was only cosmetically adjusted.

    The other area of interest is associated with an increasing signal
    for heavy rainfall for portions of West Texas into the Hill
    Country. Thunderstorms developing along the southward sagging cold
    front will tap into robust thermodynamics characterized by PWs of
    1.75 to 2.00 and MUCAPE of 2000 J/kg. This will be most impressive
    in a narrow channel immediately ahead of the cold front, and will
    support heavy rainfall rates of 2"/hr or more. The high-res CAMs
    have become more aggressive with convective coverage today, and
    although cells should move steadily S/SW, any short term training
    through modest shear along the front could produce 2-3" of rain
    with locally higher amounts. Considered an upgrade to a SLGT risk,
    especially noting the continued elevated 0-40cm soil moisture and
    general sensitivity of this region, but after coordination with
    the impacted WFOs, and due to uncertainty in storm coverage, opted
    to maintain the MRGL risk at this time.

    Weiss


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION AND THE EASTERN GREAT LAKES...

    ...East Coast States...
    Widespread showers and thunderstorms are expected from the Gulf
    Coast of Florida through the Mid-Atlantic States, and into the
    interior Northeast on Sunday.

    An anomalously strong upper closed low (NAEFS 500mb heights down to
    the 1st climatological percentile and 850mb heights below the
    climatological minimum) will be positioned over IN Sunday morning.
    This feature will begin to open during D2 as a piece of vorticity
    energy swings through the base, but this will result in a still
    highly amplified/short wavelength trough digging all the way to the
    Gulf Coast. This evolution will help strengthen a meridionally
    arcing jet streak into the Northeast and Canada such that the
    favorable diffluent RRQ will overlap the broad height falls
    downstream of the opening trough. Together, this will create a
    large expanse of impressive synoptic ascent from the Gulf Coast
    all the way into New England.

    This ascent will act upon impressive thermodynamics as tropical
    moisture gets drawn northward ahead of the system. PWs as high as
    2.25" are progged to flood northward as far as Massachusetts, with
    still impressive PWs above 1.75" as far west as the St. Lawrence
    River Valley. Together with a collocated plume of 1000+ J/kg
    MUCAPE, this will provide an environment for which thunderstorms
    will be widespread, and create numerous 1-2"/hr rain rates.
    Generally fast 0-6km mean winds of 20-30 kts should limit the
    duration of any individual cell in most areas, but this flow will
    additionally be aligned to an approaching cold front beneath the
    upper trough, suggesting the potential for repeating/training of
    cells. This has prompted a large MRGL risk expansion to encompass
    most of the eastern states, with isolated flash flood potential
    beneath any of these heavier rain rates.

    However, there appear to be two area of a more focused threat. The
    first is across the Florida Gulf Coast/Big Bend and just inland
    where heavy rain will occur again after heavy rain that is
    currently falling during D1. An additional 3-5" of rain is possible
    (30-50% chance of at least 5") due to backbuilding of cells across
    the Gulf repeating onshore with 2-3"/hr rates. Within this region,
    an enhanced slight risk was added for Taylor, Dixie, and Lafayette
    counties which is where the 2-day rainfall is expected to be
    heaviest.

    Another area of locally higher excessive rainfall risk exists along
    the eastern Great Lakes from around Cleveland, OH through Buffalo,
    NY and into the Northern Adirondacks. While instability may be a
    bit less here, this is also the region where a pivoting
    deformation axis and accompanying mid-level TROWAL may exist north
    of the closed low. This will produce some higher thermodynamics
    into which storms, which will be slow moving and training, can
    repeat with 1-2"/hr rain rates. The inherited SLGT risk was
    cosmetically adjusted for new guidance, and the urban areas will be
    most susceptible to impacts on Sunday.

    ..Southwest...
    The monsoon ridge begins to expand back to the east once again on
    Sunday, but activity is still expected to be suppressed to just
    southern AZ/NM. This will be partially due to a shortwave rotating anticylonically around the base of the ridge to enhance ascent,
    impinging into areas with favorable thermodynamics characterized by
    PWs of 1,25 to 1.5 inches, and MUCAPE above 1000 J/kg. The
    challenge Sunday is that it appears there will be some drying that
    occurs from NE to SW as a decaying front drops across Texas,
    followed by a weak surface trough as well. This suggests that
    during peak heating, there will actually be somewhat of a
    deterioration of the environment, further limiting convective
    coverage. Still, scattered thunderstorms are likely for the
    southeast portion of AZ, with some more isolated activity as far
    east as the Sacramento Mountains of NM. With sufficient bulk shear
    of 20-25 kts for modest organization, any of these storms could
    produce locally 1"/hr rain rates and instances of flash flooding.

    Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT..

    ...United States East Coast...
    The impressive upper trough/low moving across the Ohio Valley is
    progged to cutoff once again as it digs into the Southeast by
    Tuesday morning. Downstream of this anomalous feature, robust PWs
    of more than +2 sigma will flood the Atlantic Seaboard, combining
    with a ribbon of elevated instability within the deep layer WAA to
    produce an environment supportive of heavy rainfall for nearly the
    entire coast. While specific locations for heavier rainfall and a
    greater excessive rainfall risk are difficult to discern at this
    time range, it appears nearly any location that received repeating
    showers and thunderstorms with 1-2"/hr rain rates could experienced
    impacts, so the inherited MRGL risk was adjusted for newer
    guidance.

    The narrow SLGT risk for the Tri-State area of CT/NJ/NY was
    curtailed a bit on the SW side (closer to Philadelphia, PA) due to
    a slightly more progressive/eastward signal in the QPF from the
    guidance. Did not remove the SLGT risk all together due to
    extremely vulnerable soils from recent heavy rainfall in this area,
    but if the trends continue for lesser/faster QPF, this SLGT may
    also be removed with later updates.

    Additionally, there may be the need for a small SLGT across the Big
    Bend of Florida where additional heavy rain may pivot onshore
    Monday after 2-days of heavy rain this weekend. However, there is
    just enough uncertainty as to the amount of rain lingering D3 that,
    after coordination with WFO TAE, opted to maintain just the MRGL
    risk for now and re-evaluate the need for an upgrade with later
    forecasts.

    ...Southwest...
    Convection associated with the monsoon will become even less
    suppressed Monday as the ridge expands even farther east, and weak
    vorticity impulses rotate around it. Moisture and instability will
    gradually lift northward during this time, allowing for an
    expansion north of an environment supportive of heavy rain. The
    limiting factor Monday appears to be instability moreso than
    moisture, so the inherited MRGL risk was curtailed a bit from the
    north, but at least isolated instances of excessive rainfall
    leading to flash flood related impacts are expected for parts of
    AZ/NM.

    ...Northern Plains...
    A potent shortwave diving along the Canadian/United States border
    will race eastward Monday bringing height falls into the Dakotas
    and Minnesota. Downstream of this feature, brief but pinched SW
    flow will draw moisture and instability northward to create an
    environment supportive of heavy rainfall, into which a cold front
    beneath the shortwave will create enhanced ascent for convective
    development. Strong 0-6km mean winds suggests storms will move
    rapidly northeast ahead of the front, but with flow aligned
    parallel to the boundary, at least short duration training could
    occur. As rainfall rates climb to 1+"/hr, any training could create
    locally excessive rainfall as reflected by the ECMWF EFI reaching
    above 0.7 coincident with low-end probabilities for 3"/24 hr
    rainfall.

    Weiss


    Day 4 and Day 5

    Valid 12Z Tue Aug 04 2026 - 12Z Thu Aug 06 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE SOUTHWEST, PLAINS, MIDWEST, & EAST...

    ...Upper OH Valley/Cumberland Plateau/East...
    There has been a substantial change to most of the model guidance
    at 12z, with the UKMET holding serve with a more northern solution
    to the mid- to upper-level low while the other guidance has trended
    southwest. Conceptually, the non-UKMET guidance makes the most
    sense based on the position/strength of the ridge forecast to move
    over the top of the feature. However, the concern is sensitivity
    over portions of NY from recent heavy rains. Taking into account
    continuity, NY's sensitivity, and the southwest trend of the
    guidance led to a bit of southwest broadening of the Marginal Risk
    area. No matter where the system is, some cool air aloft along with
    ample moisture and resultant instability could lead to hourly rain
    amounts up to 2.5", which would be problematic in rugged terrain,
    sensitive soils, and urban areas. Should the UKMET shift southwest
    towards the remainder of the guidance later, we can shave off the
    northeast side of the Marginal Risk area at that time.

    ...Southwest/Southern High Plains...
    For both Tuesday and Wednesday, a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.

    ...Central Plains into the Mid to Upper MS Valley...
    A surface frontal boundary is expected to be slow-moving Tuesday
    and Wednesday from the Central Plains, east- northeastward into the
    Mid to Upper MS Valley into the Great Lakes. This front will be
    situated along the southern edge of the westerlies where shortwave
    energy pushing east northeastward near the front will support the
    potential for organized convection both days. PW values expected
    to be slightly above average...1.5 to 1.75"+ in the vicinity of
    this front, supporting the potential of hourly rain amounts to 2.5"
    where convection does organize and isolated runoff issues. For the
    moment, coverage/amounts appear shy of a Slight Risk, so let the
    Marginal Risk continue from continuity.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_I8fktITP-rtDKwcK1YU3zWpUJPBmar_8OO4KgZxlhopc7gfUU9ttH9T5MuWSF07P4Xd6opGaadR1oTlzaC97DLZVcg$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_I8fktITP-rtDKwcK1YU3zWpUJPBmar_8OO4KgZxlhopc7gfUU9ttH9T5MuWSF07P4Xd6opGaadR1oTlzaC9fihyQEc$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_I8fktITP-rtDKwcK1YU3zWpUJPBmar_8OO4KgZxlhopc7gfUU9ttH9T5MuWSF07P4Xd6opGaadR1oTlzaC92IZLyVY$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 2 00:25:24 2026
    FOUS30 KWBC 020025
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    825 PM EDT Sat Aug 1 2026

    Day 1
    Valid 01Z Sun Aug 02 2026 - 12Z Sun Aug 02 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE MIDWEST, NEW MEXICO, AND THE GULF COAST...

    ...Portions of the Midwest...
    An anomalously strong upper low will continue to pivot slowly
    eastward, reaching central Indiana by Sunday morning. This closed
    low fosters divergence aloft to its east, while the accompanying
    occluded surface low and trailing cold front push into/through
    portions of the Ohio and Tennessee Valleys. There will be moisture
    to spare across the region, with precipitable water values
    approaching 2" and sufficient instability for heavy rain concerns.
    Across IL & IN an impressive deformation axis will exist N/NW of
    the mid- level low as it pivots E/SE, and will drive ascent into an
    impressive (especially for August 1) TROWAL as the accompanying
    theta-e ridge pivots cyclonically around the system. This will
    result not only as a region of increased instability and moisture,
    but also a greater training risk as propagation vectors and mean
    winds become increasingly anti- parallel. This suggests a high
    threat for backbuilding and repeating cells, through which the
    1-2"/hr rain amounts could cause locally more than 5" of rain. This
    segment of the Slight Risk from continuity was maintained, but the
    previous portion to the south near the Cumberland Plateau was
    downgraded to a Marginal as any additional thunderstorm activity
    should be progressive.

    ...North-Central/Northeast Gulf coast...
    An approaching front backs the low-level flow to west to west-
    southwest. A deep layer cyclone to the north aids divergence aloft.
    With precipitable water values approaching 2.5" and ample
    instability moving ashore from the Gulf, hourly rain amounts to 3"
    are possible in this region. Both the 18z HREF/12z REFS indicate
    that heavy rain could fall quickly during the 06z-12z period, with
    local totals of 5-6" within the realm of possibility. Kept the Gulf
    Coast portions of the Slight Risk though extended it westward
    through Southeast LA in concert with the HREF/REFS guidance. The
    higher end Slight Risk area was maintained near Cedar Key.

    ...Southern Rockies/High Plains to the Texas Hill Country...
    Convection moving southward through New Mexico could cause heavy
    rainfall particularly in and near southeast portions of the state
    per 18z HREF/12z REFS guidance in the very short term, with
    activity waning after 05z. Both the Marginal and Slight Risks
    across the region were shrunk a bit from continuity due to
    convective propagation and the 18z HREF/12z REFS guidance. Until
    activity fades, hourly amounts to 2" should be possible locally.

    Roth


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION AND THE EASTERN GREAT LAKES...

    ...East Coast States...
    Widespread showers and thunderstorms are expected from the Gulf
    Coast of Florida through the Mid-Atlantic States, and into the
    interior Northeast on Sunday.

    An anomalously strong upper closed low (NAEFS 500mb heights down to
    the 1st climatological percentile and 850mb heights below the
    climatological minimum) will be positioned over IN Sunday morning.
    This feature will begin to open during D2 as a piece of vorticity
    energy swings through the base, but this will result in a still
    highly amplified/short wavelength trough digging all the way to the
    Gulf Coast. This evolution will help strengthen a meridionally
    arcing jet streak into the Northeast and Canada such that the
    favorable diffluent RRQ will overlap the broad height falls
    downstream of the opening trough. Together, this will create a
    large expanse of impressive synoptic ascent from the Gulf Coast
    all the way into New England.

    This ascent will act upon impressive thermodynamics as tropical
    moisture gets drawn northward ahead of the system. PWs as high as
    2.25" are progged to flood northward as far as Massachusetts, with
    still impressive PWs above 1.75" as far west as the St. Lawrence
    River Valley. Together with a collocated plume of 1000+ J/kg
    MUCAPE, this will provide an environment for which thunderstorms
    will be widespread, and create numerous 1-2"/hr rain rates.
    Generally fast 0-6km mean winds of 20-30 kts should limit the
    duration of any individual cell in most areas, but this flow will
    additionally be aligned to an approaching cold front beneath the
    upper trough, suggesting the potential for repeating/training of
    cells. This has prompted a large MRGL risk expansion to encompass
    most of the eastern states, with isolated flash flood potential
    beneath any of these heavier rain rates.

    However, there appear to be two area of a more focused threat. The
    first is across the Florida Gulf Coast/Big Bend and just inland
    where heavy rain will occur again after heavy rain that is
    currently falling during D1. An additional 3-5" of rain is possible
    (30-50% chance of at least 5") due to backbuilding of cells across
    the Gulf repeating onshore with 2-3"/hr rates. Within this region,
    an enhanced slight risk was added for Taylor, Dixie, and Lafayette
    counties which is where the 2-day rainfall is expected to be
    heaviest.

    Another area of locally higher excessive rainfall risk exists along
    the eastern Great Lakes from around Cleveland, OH through Buffalo,
    NY and into the Northern Adirondacks. While instability may be a
    bit less here, this is also the region where a pivoting
    deformation axis and accompanying mid-level TROWAL may exist north
    of the closed low. This will produce some higher thermodynamics
    into which storms, which will be slow moving and training, can
    repeat with 1-2"/hr rain rates. The inherited SLGT risk was
    cosmetically adjusted for new guidance, and the urban areas will be
    most susceptible to impacts on Sunday.

    ..Southwest...
    The monsoon ridge begins to expand back to the east once again on
    Sunday, but activity is still expected to be suppressed to just
    southern AZ/NM. This will be partially due to a shortwave rotating anticyclonically around the base of the ridge to enhance ascent,
    impinging into areas with favorable thermodynamics characterized by
    PWs of 1,25 to 1.5 inches, and MUCAPE above 1000 J/kg. The
    challenge Sunday is that it appears there will be some drying that
    occurs from NE to SW as a decaying front drops across Texas,
    followed by a weak surface trough as well. This suggests that
    during peak heating, there will actually be somewhat of a
    deterioration of the environment, further limiting convective
    coverage. Still, scattered thunderstorms are likely for the
    southeast portion of AZ, with some more isolated activity as far
    east as the Sacramento Mountains of NM. With sufficient bulk shear
    of 20-25 kts for modest organization, any of these storms could
    produce locally 1"/hr rain rates and instances of flash flooding.

    Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT..

    ...United States East Coast...
    The impressive upper trough/low moving across the Ohio Valley is
    progged to cutoff once again as it digs into the Southeast by
    Tuesday morning. Downstream of this anomalous feature, robust PWs
    of more than +2 sigma will flood the Atlantic Seaboard, combining
    with a ribbon of elevated instability within the deep layer WAA to
    produce an environment supportive of heavy rainfall for nearly the
    entire coast. While specific locations for heavier rainfall and a
    greater excessive rainfall risk are difficult to discern at this
    time range, it appears nearly any location that received repeating
    showers and thunderstorms with 1-2"/hr rain rates could experienced
    impacts, so the inherited MRGL risk was adjusted for newer
    guidance.

    The narrow SLGT risk for the Tri-State area of CT/NJ/NY was
    curtailed a bit on the SW side (closer to Philadelphia, PA) due to
    a slightly more progressive/eastward signal in the QPF from the
    guidance. Did not remove the SLGT risk all together due to
    extremely vulnerable soils from recent heavy rainfall in this area,
    but if the trends continue for lesser/faster QPF, this SLGT may
    also be removed with later updates.

    Additionally, there may be the need for a small SLGT across the Big
    Bend of Florida where additional heavy rain may pivot onshore
    Monday after 2-days of heavy rain this weekend. However, there is
    just enough uncertainty as to the amount of rain lingering D3 that,
    after coordination with WFO TAE, opted to maintain just the MRGL
    risk for now and re-evaluate the need for an upgrade with later
    forecasts.

    ...Southwest...
    Convection associated with the monsoon will become even less
    suppressed Monday as the ridge expands even farther east, and weak
    vorticity impulses rotate around it. Moisture and instability will
    gradually lift northward during this time, allowing for an
    expansion north of an environment supportive of heavy rain. The
    limiting factor Monday appears to be instability moreso than
    moisture, so the inherited MRGL risk was curtailed a bit from the
    north, but at least isolated instances of excessive rainfall
    leading to flash flood related impacts are expected for parts of
    AZ/NM.

    ...Northern Plains...
    A potent shortwave diving along the Canadian/United States border
    will race eastward Monday bringing height falls into the Dakotas
    and Minnesota. Downstream of this feature, brief but pinched SW
    flow will draw moisture and instability northward to create an
    environment supportive of heavy rainfall, into which a cold front
    beneath the shortwave will create enhanced ascent for convective
    development. Strong 0-6km mean winds suggests storms will move
    rapidly northeast ahead of the front, but with flow aligned
    parallel to the boundary, at least short duration training could
    occur. As rainfall rates climb to 1+"/hr, any training could create
    locally excessive rainfall as reflected by the ECMWF EFI reaching
    above 0.7 coincident with low-end probabilities for 3"/24 hr
    rainfall.

    Weiss


    Day 4 and Day 5

    Valid 12Z Tue Aug 04 2026 - 12Z Thu Aug 06 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE SOUTHWEST, PLAINS, MIDWEST, & EAST...

    ...Upper OH Valley/Cumberland Plateau/East...
    There has been a substantial change to most of the model guidance
    at 12z, with the UKMET holding serve with a more northern solution
    to the mid- to upper-level low while the other guidance has trended
    southwest. Conceptually, the non-UKMET guidance makes the most
    sense based on the position/strength of the ridge forecast to move
    over the top of the feature. However, the concern is sensitivity
    over portions of NY from recent heavy rains. Taking into account
    continuity, NY's sensitivity, and the southwest trend of the
    guidance led to a bit of southwest broadening of the Marginal Risk
    area. No matter where the system is, some cool air aloft along with
    ample moisture and resultant instability could lead to hourly rain
    amounts up to 2.5", which would be problematic in rugged terrain,
    sensitive soils, and urban areas. Should the UKMET shift southwest
    towards the remainder of the guidance later, we can shave off the
    northeast side of the Marginal Risk area at that time.

    ...Southwest/Southern High Plains...
    For both Tuesday and Wednesday, a marginal risk was depicted for
    monsoonal convection across southern Arizona into New Mexico. Not a
    lot of confidence with qpf details here, but locally heavy rains
    and isolated runoff issues possible in the above average PW values
    expected across this area.

    ...Central Plains into the Mid to Upper MS Valley...
    A surface frontal boundary is expected to be slow-moving Tuesday
    and Wednesday from the Central Plains, east- northeastward into the
    Mid to Upper MS Valley into the Great Lakes. This front will be
    situated along the southern edge of the westerlies where shortwave
    energy pushing east northeastward near the front will support the
    potential for organized convection both days. PW values expected
    to be slightly above average...1.5 to 1.75"+ in the vicinity of
    this front, supporting the potential of hourly rain amounts to 2.5"
    where convection does organize and isolated runoff issues. For the
    moment, coverage/amounts appear shy of a Slight Risk, so let the
    Marginal Risk continue from continuity.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!-IfO8aasU0_Pv2xgG9vIyfnKggnAlq6Z5PfdNFMKi2nxpGhzoU6oIC_Pcwq6ScmV1jcXG-iil60mAk-oVW9Ta-VsKEQ$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!-IfO8aasU0_Pv2xgG9vIyfnKggnAlq6Z5PfdNFMKi2nxpGhzoU6oIC_Pcwq6ScmV1jcXG-iil60mAk-oVW9TZm8stNY$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!-IfO8aasU0_Pv2xgG9vIyfnKggnAlq6Z5PfdNFMKi2nxpGhzoU6oIC_Pcwq6ScmV1jcXG-iil60mAk-oVW9TEEoIOcc$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 2 08:29:52 2026
    FOUS30 KWBC 020829
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    429 AM EDT Sun Aug 2 2026

    Day 1
    Valid 01Z Sun Aug 02 2026 - 12Z Sun Aug 02 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, COASTAL NORTH CAROLINA AND THE EASTERN GREAT LAKES
    INTO THE NORTHEAST AND NORTHERN/CENTRAL APPALACHIANS...

    ...East Coast States...

    Widespread showers and thunderstorms are expected from the Gulf
    Coast of Florida through the Mid-Atlantic States, and into the
    interior Northeast. A highly amplified trough will be tracking
    though the region. A strong upper level jet will help provide
    impressive synoptic ascent from the Gulf Coast all the way into New
    England. Meanwhile Gulf moisture will be drawn northward ahead of
    the system with PW values climbing into the 2-2.25 inches range.
    Widespread thunderstorm are expected to break out and capable to
    produce rain rates of 1-2 inches/hour with the potential for
    repeating/training of cells. A broad Marginal Risk are spans from
    the eastern Gulf Coast up the Eastern Seaboard to th Northeast and
    Ohio Valley.

    There are three areas with a more focused threat. The first is
    across the Florida Gulf Coast/Big Bend and just inland where heavy
    rain will occur over recently saturated soils. An additional 3-5
    inches of rain is possible (30-50% chance of at least 5 inches)
    due to backbuilding of cells across the Gulf repeating onshore with
    2-3 inches/hour rates. Within this region, an enhanced slight risk
    was added for Taylor, Dixie, and Lafayette counties which is where
    the 2-day rainfall is expected to be heaviest.

    Another area of locally higher excessive rainfall risk exists along
    the eastern Great Lakes from around Cleveland, Ohio through
    Buffalo, New York and into the Northern Adirondacks and southward
    for the Central Appalachians where there is a Slight Risk for
    excessive rainfall. While instability may be a bit less here, this
    is also the region where a pivoting deformation axis and
    accompanying mid- level TROWAL may exist north of the closed low.
    This will produce some higher thermodynamics into which storms,
    which will be slow moving and training, can repeat with 1-2
    inches/hour rain rates.

    And the third area is for coastal North Carolina where there is a
    signal for 2-5 inches of rainfall too fall over recently saturated
    soils. A Slight Risk area was raised for this part of the state.

    ..Southwest...

    During this time the ridge will be expanding eastward however the
    convective activity is expected to stay suppressed across Arizona,
    New Mexico and West Texas. The challenge Sunday is that it appears
    there will be some drying that occurs from NE to SW as a decaying
    front drops across Texas, followed by a weak surface trough as
    well. This suggests that during peak heating, there will actually
    be somewhat of a deterioration of the environment, further limiting
    convective coverage. Any storms that do develop will have the
    potential to yield local hourly rates of 1 inch/hour that lead to
    isolated instances of flash flooding.

    Campbell/Weiss


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT, COASTAL CAROLINAS
    AND BIG BEND OF FLORIDA...

    ...East Coast...

    The impressive upper trough/low moving across the Ohio Valley is
    progged to cutoff once again as it digs into the Southeast by
    Tuesday morning. Downstream of this anomalous feature, robust PWs
    of more than +2 sigma will flood the Atlantic Seaboard, combining
    with a ribbon of elevated instability within the deep layer WAA to
    produce an environment supportive of heavy rainfall for nearly the
    entire coast. While specific locations for heavier rainfall and a
    greater excessive rainfall risk are difficult to discern at this
    time range, it appears nearly any location that received repeating
    showers and thunderstorms with 1-2 inches/hour rain rates could
    experienced impacts. The Marginal Risk area stretching from Florida
    to Maine was maintained.

    The narrow Slight risk for the Tri-State area of CT/NJ/NY and
    northwest Rhode Island was maintained due to extremely vulnerable
    soils from recent heavy rainfall in this area. A small Slight
    Risk area was raised for the Big Bend of Florida where additional
    heavy rain may pivot onshore Monday after 2-days of heavy rain this
    weekend. A Slight Risk was also raised for coastal areas of South
    and North Carolina given additional rainfall is expected to fall
    over very saturated soils.

    ...Southwest...

    The ridge will continue to expand farther east while weak
    vorticity impulses rotate around it. Moisture and instability will
    gradually lift northward during this time, allowing for an
    expansion north of an environment supportive of heavy rain. The
    limiting factor Monday appears to be instability. The Marginal Risk
    area was maintained for isolated instances of excessive rainfall
    leading to flash flood related impacts are expected for parts of
    Arizona, New Mexico and far western Texas.

    ...Northern Plains...

    A shortwave will quickly track along the International border
    bringing height falls to the Dakotas and Minnesota. Southwest flow
    will direct Gulf moisture and instability northward to help support
    the development of heavy rainfall. Storm motion is expected to be
    quite progressive however there may be briefs periods where training/backbuilding occurs. As rainfall rates climb to 1+
    inches/hour, any training could create locally excessive rainfall.

    Campbell/Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE SOUTHWEST, PLAINS AND MIDWEST, SOUTH FLORIDA AND THE EAST...

    ...Upper Ohio Valley/Cumberland Plateau/East...

    Cool air aloft along with ample moisture and instability could
    lead to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    There is some overlap with areas that had rainfall during the Day 1
    and 2 period, thus maintaining soil sensitivity for potential
    flooding issues.

    ...Southwest/Southern High Plains...

    A Marginal Risk for monsoonal convection across southern Arizona,
    New Mexico, southern Colorado and into the Texas Panhandle was
    maintained for this period. Locally heavy rains and isolated
    runoff issues will be possible in the above average PW values
    expected across this area.

    ...Central Plains into the Mid to Upper Mississippi Valley...

    A slow moving front pushing through the Central Plains and
    portions of the Mississippi Valley will trigger organized
    convection for ahead along and ahead of the boundary. PW values
    expected to be slightly above average...1.5 to 1.75"+ in the
    vicinity of this front, supporting the potential of hourly rain
    amounts to 2.5" where convection does organize and isolated runoff
    issues. A Marginal Risk remains in effect for this part of the
    country.

    ...South Florida...

    Onshore flow will trigger showers and thunderstorms capable of
    producing 1 to 2+ inches of rainfall that may lead to isolated
    flash flooding/ponding. A Marginal Risk area was raised for this
    period.

    Campbell


    Day 4 and Day 5

    Valid 12Z Wed Aug 05 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MID WEST...

    ...Mid to Upper Mississippi Valley/Mid West...
    There is fairly good model qpf agreement on heavy precip potential
    along and ahead of the cold front sinking southeastward day 4 from
    the Upper MS Valley/Upper Lakes region. Favorable right entrance
    region jet dynamics along the southern edge of the westerlies
    should enhance uvvs in an axis of 1.75"+ PW values in the vicinity
    of this front. There is a good chance of organized convection along
    and ahead of the front Wednesday night into the early hours of
    Thursday, with potential for localized runoff issues. The slight
    risk area was drawn to encompass the model qpf axis consensus from
    southern IA/far northern MO, eastward into northern IL/far southern
    WI, including the Chicago metro area.

    ...Central Plains into the Lower Missouri Valley...
    By day 5...additional shortwave energy moving along the southern
    edge of the westerlies into the Central High Plains may ignite
    another round of organized convection along the southward moving
    cold front from KS into MO. Not as good of agreement model qpf wise
    day 5 compared to day 4 farther to the northeast, but with low
    level southerly flow expected to strengthen Thursday night into
    early Friday morning into this front, locally heavy rains are
    possible. At the moment, the risk level along the front over the
    Central Plains toward the Lower MO Valley kept at marginal for day
    5.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper trof across the eastern U.S. by the
    beginning of the day 4/5 time period, should continue to weaken.
    However, an axis of high PW values...1.5-1.75"+, will remain across
    much of the eastern U.S. in the Wednesday to Friday time frame.
    This will support additional widespread scattered showers in this
    high PW axis, with locally heavy rains and runoff issues possible.
    A marginal risk was continued for both day 4 and 5 across the
    Southern to Central Appalachians into the northern Mid- Atlantic.
    After several days of locally heavy rains during the short range
    period, FFG values will likely be lower through the Southern to
    Central Appalachians into the Northern Mid Atlantic. This may
    warrant a greater risk area across these regions with future
    updates.

    ...Southwest/Southern High Plains...
    For the 1200 UTC Wednesday to 1200 UTC Friday time period, a
    marginal risk was depicted across much of AZ/NM for monsoonal
    convection. Continued low confidence with qpf details here, but
    locally heavy rains and isolated runoff issues possible in the
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!9Vv3Of6Ho5uRYnd2sF07XROq09mb0HHrOru44EQWr0VvsDb_fl8TEPDYHlNH68aBMIJxO95wKDOYfPgw8eZSjg7whtc$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!9Vv3Of6Ho5uRYnd2sF07XROq09mb0HHrOru44EQWr0VvsDb_fl8TEPDYHlNH68aBMIJxO95wKDOYfPgw8eZSrS5eK9g$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!9Vv3Of6Ho5uRYnd2sF07XROq09mb0HHrOru44EQWr0VvsDb_fl8TEPDYHlNH68aBMIJxO95wKDOYfPgw8eZSWeF3LRI$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 2 15:55:46 2026
    FOUS30 KWBC 021555
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1155 AM EDT Sun Aug 2 2026

    Day 1
    Valid 16Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, COASTAL NORTH CAROLINA, AND THE EASTERN GREAT LAKES
    INTO THE NORTHERN/CENTRAL APPALACHIANS...

    ...East Coast States...
    Anomalous upper low will continue to plague the eastern portions of
    the CONUS with broad and impressive synoptic ascent impinging into
    extreme thermodynamics. Morning 12Z U/A soundings from a variety of
    sites in the east measured PWs from 1.8 to 2.2 inches, well above
    the 90th percentile, and with additional moistening expected
    through today, a broad plume of +2-+2.5 sigma PWs are anticipated
    to stretch from Florida to New England. This will provide an
    environment favorable for heavy rainfall within convection almost
    anywhere from Florida to Upstate NY. The high-res CAMs support this
    idea also, with widespread convection continuing through the day,
    and isolated extreme rainfall events with small spatial coverage of
    4-6 inches of rain, similar to what occurred near Mt Airy, NC
    yesterday, are possible within the inherited broad MRGL risk, and
    if this occurs along the I-95 corridor between Washington, D.C. and
    New York, more substantial impacts could occur.

    While the forcing will be generally broad and diffuse, a few
    focused areas of heavier rainfall and greater flash flood potential
    exist.

    The first is along the Florida Panhandle and into the Big Bend.
    Not only is this area saturated from heavy rainfall on Saturday,
    but pronounced onshore flow from the Gulf drawing impressive
    PWs/CAPE onshore ahead of a cold front will again result in
    repeating rounds of thunderstorms with 2-3"/hr rain rates which has
    a 40-50% chance of creating more than 5" of rain (HREF and REFS
    probabilities). This heavy rain falling atop saturated soils will
    likely lead to rapid runoff and instances of flash flooding, so the
    inherited SLGT (and enhanced SLGT) was only cosmetically adjusted.

    Farther north into the eastern Great Lakes and Central
    Appalachians, the combination of a TROWAL/deformation axis and
    vulnerable soils also create a more robust excessive rainfall risk
    today. While SBCAPE into the Great Lakes may be somewhat more
    limited, the theta-e ridge rotating into a TROWAL will sufficiently
    enhanced instability to support 1+"/hr rain rates with
    slow/backbuilding motions. This will support a stripe of 3-5" of
    rain from near Cleveland, OH through Buffalo, NY and into far
    northern Upstate NY, where the SLGT risk continues. A bit farther
    south into the Appalachians any periods of heavy rain atop
    vulnerable terrains/soils will also enhance the risk today.

    Finally, A SLGT risk exists for extreme coastal NC where a coastal
    band of heavy rain may develop. The guidance varies with how far
    onshore this heavy rain may pivot, but if this band does move
    onshore (generally Cape Fear to Cape Hatteras) it would suggest
    pronounced training of 2"/hr rain rates. Most of this area has
    been dry outside of far eastern NC and the Outer Banks, and 3-hr
    FFG is generally 3-4" which has only a very minor threat of
    exceedance from the HREF. Due to the potential for training if this
    band comes onshore, left the SLGT in place but made some minor
    cosmetic adjustments.

    ...South Texas...
    A cold front dropping into South Texas is the focus for slow moving thunderstorms this morning. The environment downstream of this
    front is favorable for heavy rain rates with PWs of +2 sigma
    overlapping 2000-3000 J/kg MUCAPE. The CAMs are not extremely
    excited with this event, but may be under-representing the
    potential as the ingredients remain in place as the front stalls
    before weakening. Rainfall rates of 2"/hr are likely at times,
    which despite a slow southern advance, could produce 2-4" of rain
    and isolated flash flooding.

    ..Southwest...
    As the monsoon ridge expands a bit northeast today, convection will
    again develop across the Southwest. While the past few days have
    featured generally scattered convection focused in AZ/NM, a surge
    of instability peeking into CO may allow for a northward expansion
    of thunderstorm activity today. For this reason, the inherited MRGL
    risk was expanded a bit northeast for rainfall rates that may
    exceed 1"/hr at times, especially in the presence of enhanced 25-35
    kts shear which could organize cells into clusters across the area.

    Weiss


    Day 2
    Valid 12Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT, COASTAL CAROLINAS
    AND BIG BEND OF FLORIDA...

    ...East Coast...

    The impressive upper trough/low moving across the Ohio Valley is
    progged to cutoff once again as it digs into the Southeast by
    Tuesday morning. Downstream of this anomalous feature, robust PWs
    of more than +2 sigma will flood the Atlantic Seaboard, combining
    with a ribbon of elevated instability within the deep layer WAA to
    produce an environment supportive of heavy rainfall for nearly the
    entire coast. While specific locations for heavier rainfall and a
    greater excessive rainfall risk are difficult to discern at this
    time range, it appears nearly any location that received repeating
    showers and thunderstorms with 1-2 inches/hour rain rates could
    experienced impacts. The Marginal Risk area stretching from Florida
    to Maine was maintained.

    The narrow Slight risk for the Tri-State area of CT/NJ/NY and
    northwest Rhode Island was maintained due to extremely vulnerable
    soils from recent heavy rainfall in this area. A small Slight
    Risk area was raised for the Big Bend of Florida where additional
    heavy rain may pivot onshore Monday after 2-days of heavy rain this
    weekend. A Slight Risk was also raised for coastal areas of South
    and North Carolina given additional rainfall is expected to fall
    over very saturated soils.

    ...Southwest...

    The ridge will continue to expand farther east while weak
    vorticity impulses rotate around it. Moisture and instability will
    gradually lift northward during this time, allowing for an
    expansion north of an environment supportive of heavy rain. The
    limiting factor Monday appears to be instability. The Marginal Risk
    area was maintained for isolated instances of excessive rainfall
    leading to flash flood related impacts are expected for parts of
    Arizona, New Mexico and far western Texas.

    ...Northern Plains...

    A shortwave will quickly track along the International border
    bringing height falls to the Dakotas and Minnesota. Southwest flow
    will direct Gulf moisture and instability northward to help support
    the development of heavy rainfall. Storm motion is expected to be
    quite progressive however there may be briefs periods where training/backbuilding occurs. As rainfall rates climb to 1+
    inches/hour, any training could create locally excessive rainfall.

    Campbell/Weiss


    Day 3
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE SOUTHWEST, PLAINS AND MIDWEST, SOUTH FLORIDA AND THE EAST...

    ...Upper Ohio Valley/Cumberland Plateau/East...

    Cool air aloft along with ample moisture and instability could
    lead to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    There is some overlap with areas that had rainfall during the Day 1
    and 2 period, thus maintaining soil sensitivity for potential
    flooding issues.

    ...Southwest/Southern High Plains...

    A Marginal Risk for monsoonal convection across southern Arizona,
    New Mexico, southern Colorado and into the Texas Panhandle was
    maintained for this period. Locally heavy rains and isolated
    runoff issues will be possible in the above average PW values
    expected across this area.

    ...Central Plains into the Mid to Upper Mississippi Valley...

    A slow moving front pushing through the Central Plains and
    portions of the Mississippi Valley will trigger organized
    convection for ahead along and ahead of the boundary. PW values
    expected to be slightly above average...1.5 to 1.75"+ in the
    vicinity of this front, supporting the potential of hourly rain
    amounts to 2.5" where convection does organize and isolated runoff
    issues. A Marginal Risk remains in effect for this part of the
    country.

    ...South Florida...

    Onshore flow will trigger showers and thunderstorms capable of
    producing 1 to 2+ inches of rainfall that may lead to isolated
    flash flooding/ponding. A Marginal Risk area was raised for this
    period.

    Campbell


    Day 4 and Day 5

    Valid 12Z Wed Aug 05 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MID WEST...

    ...Mid to Upper Mississippi Valley/Mid West...
    There is fairly good model qpf agreement on heavy precip potential
    along and ahead of the cold front sinking southeastward day 4 from
    the Upper MS Valley/Upper Lakes region. Favorable right entrance
    region jet dynamics along the southern edge of the westerlies
    should enhance uvvs in an axis of 1.75"+ PW values in the vicinity
    of this front. There is a good chance of organized convection along
    and ahead of the front Wednesday night into the early hours of
    Thursday, with potential for localized runoff issues. The slight
    risk area was drawn to encompass the model qpf axis consensus from
    southern IA/far northern MO, eastward into northern IL/far southern
    WI, including the Chicago metro area.

    ...Central Plains into the Lower Missouri Valley...
    By day 5...additional shortwave energy moving along the southern
    edge of the westerlies into the Central High Plains may ignite
    another round of organized convection along the southward moving
    cold front from KS into MO. Not as good of agreement model qpf wise
    day 5 compared to day 4 farther to the northeast, but with low
    level southerly flow expected to strengthen Thursday night into
    early Friday morning into this front, locally heavy rains are
    possible. At the moment, the risk level along the front over the
    Central Plains toward the Lower MO Valley kept at marginal for day
    5.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper trof across the eastern U.S. by the
    beginning of the day 4/5 time period, should continue to weaken.
    However, an axis of high PW values...1.5-1.75"+, will remain across
    much of the eastern U.S. in the Wednesday to Friday time frame.
    This will support additional widespread scattered showers in this
    high PW axis, with locally heavy rains and runoff issues possible.
    A marginal risk was continued for both day 4 and 5 across the
    Southern to Central Appalachians into the northern Mid- Atlantic.
    After several days of locally heavy rains during the short range
    period, FFG values will likely be lower through the Southern to
    Central Appalachians into the Northern Mid Atlantic. This may
    warrant a greater risk area across these regions with future
    updates.

    ...Southwest/Southern High Plains...
    For the 1200 UTC Wednesday to 1200 UTC Friday time period, a
    marginal risk was depicted across much of AZ/NM for monsoonal
    convection. Continued low confidence with qpf details here, but
    locally heavy rains and isolated runoff issues possible in the
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!5YbFmF76ByhI36X7Fn4v9hCqXKS5BCcqDlScTFIOptWlBvtAgKTRBGWrYTV4rCHy74DZJ5x89g0OY7Yl2Mp3dQTV__I$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!5YbFmF76ByhI36X7Fn4v9hCqXKS5BCcqDlScTFIOptWlBvtAgKTRBGWrYTV4rCHy74DZJ5x89g0OY7Yl2Mp3j1Ym_Ac$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!5YbFmF76ByhI36X7Fn4v9hCqXKS5BCcqDlScTFIOptWlBvtAgKTRBGWrYTV4rCHy74DZJ5x89g0OY7Yl2Mp3drvLu_g$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 2 19:19:50 2026
    FOUS30 KWBC 021919
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    319 PM EDT Sun Aug 2 2026

    Day 1
    Valid 16Z Sun Aug 02 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA BIG
    BEND REGION, COASTAL NORTH CAROLINA, AND THE EASTERN GREAT LAKES
    INTO THE NORTHERN/CENTRAL APPALACHIANS...

    ...East Coast States...
    Anomalous upper low will continue to plague the eastern portions of
    the CONUS with broad and impressive synoptic ascent impinging into
    extreme thermodynamics. Morning 12Z U/A soundings from a variety of
    sites in the east measured PWs from 1.8 to 2.2 inches, well above
    the 90th percentile, and with additional moistening expected
    through today, a broad plume of +2-+2.5 sigma PWs are anticipated
    to stretch from Florida to New England. This will provide an
    environment favorable for heavy rainfall within convection almost
    anywhere from Florida to Upstate NY. The high-res CAMs support this
    idea also, with widespread convection continuing through the day,
    and isolated extreme rainfall events with small spatial coverage of
    4-6 inches of rain, similar to what occurred near Mt Airy, NC
    yesterday, are possible within the inherited broad MRGL risk, and
    if this occurs along the I-95 corridor between Washington, D.C. and
    New York, more substantial impacts could occur.

    While the forcing will be generally broad and diffuse, a few
    focused areas of heavier rainfall and greater flash flood potential
    exist.

    The first is along the Florida Panhandle and into the Big Bend.
    Not only is this area saturated from heavy rainfall on Saturday,
    but pronounced onshore flow from the Gulf drawing impressive
    PWs/CAPE onshore ahead of a cold front will again result in
    repeating rounds of thunderstorms with 2-3"/hr rain rates which has
    a 40-50% chance of creating more than 5" of rain (HREF and REFS
    probabilities). This heavy rain falling atop saturated soils will
    likely lead to rapid runoff and instances of flash flooding, so the
    inherited SLGT (and enhanced SLGT) was only cosmetically adjusted.

    Farther north into the eastern Great Lakes and Central
    Appalachians, the combination of a TROWAL/deformation axis and
    vulnerable soils also create a more robust excessive rainfall risk
    today. While SBCAPE into the Great Lakes may be somewhat more
    limited, the theta-e ridge rotating into a TROWAL will sufficiently
    enhanced instability to support 1+"/hr rain rates with
    slow/backbuilding motions. This will support a stripe of 3-5" of
    rain from near Cleveland, OH through Buffalo, NY and into far
    northern Upstate NY, where the SLGT risk continues. A bit farther
    south into the Appalachians any periods of heavy rain atop
    vulnerable terrains/soils will also enhance the risk today.

    Finally, A SLGT risk exists for extreme coastal NC where a coastal
    band of heavy rain may develop. The guidance varies with how far
    onshore this heavy rain may pivot, but if this band does move
    onshore (generally Cape Fear to Cape Hatteras) it would suggest
    pronounced training of 2"/hr rain rates. Most of this area has
    been dry outside of far eastern NC and the Outer Banks, and 3-hr
    FFG is generally 3-4" which has only a very minor threat of
    exceedance from the HREF. Due to the potential for training if this
    band comes onshore, left the SLGT in place but made some minor
    cosmetic adjustments.

    ...South Texas...
    A cold front dropping into South Texas is the focus for slow moving thunderstorms this morning. The environment downstream of this
    front is favorable for heavy rain rates with PWs of +2 sigma
    overlapping 2000-3000 J/kg MUCAPE. The CAMs are not extremely
    excited with this event, but may be under-representing the
    potential as the ingredients remain in place as the front stalls
    before weakening. Rainfall rates of 2"/hr are likely at times,
    which despite a slow southern advance, could produce 2-4" of rain
    and isolated flash flooding.

    ..Southwest...
    As the monsoon ridge expands a bit northeast today, convection will
    again develop across the Southwest. While the past few days have
    featured generally scattered convection focused in AZ/NM, a surge
    of instability peeking into CO may allow for a northward expansion
    of thunderstorm activity today. For this reason, the inherited MRGL
    risk was expanded a bit northeast for rainfall rates that may
    exceed 1"/hr at times, especially in the presence of enhanced 25-35
    kts shear which could organize cells into clusters across the area.

    Weiss


    Day 2
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT, AS WELL AS FOR THE COASTAL CAROLINAS, THE BIG BEND OF FLORIDA, AND FAR SOUTHERN ARIZONA...

    ...East Coast...
    The anomalous upper trough plaguing the eastern 1/3 of the CONUS
    will persist on Monday, but with a different evolution. A
    shortwave trough rotating through the longwave feature will help
    close off a mid-level low center over northern GA, driving subtle
    height rises to its north, but with subtle impulses continuing to
    rotate cyclonically around it. At the same time, a jet streak
    pivoting into New England will intensify as it arcs
    poleward, leaving its favorable RRQ for ascent over the Mid- Atlantic/Northeast. Together, this again creates broad deep layer
    ascent along most of the East Coast, acting upon robust
    thermodynamics to create widespread thunderstorms with heavy rain
    rates.

    While once again the forcing will be somewhat diffuse and broad,
    leading to widespread scattered convection as reflected by most of
    the available high-res CAMs. Locally enhanced ascent along a slow eastward-advancing cold front will help organize some convection
    along it. This convergence combined with bulk shear of 20-25 kts
    will lead to clusters/multi-cells that will train thanks to
    boundary-parallel mean flow to lengthen the duration of heavy rain
    rates. With both HREF and REFS probabilities indicating a 30-60% of
    1"/hr or more rates, where any convection can organize or train,
    this could produce 3-5" of rain.

    The most likely locations for this heavier rainfall are across the
    Tri-State area of CT/NY/NJ, and down towards Philadelphia, extreme
    eastern North Carolina, and the Florida Big Bend region. Inherited
    SLGT risks across these focused areas remain both due to the
    potential organized convection on Monday, but also since all three
    have already vulnerable soils due to recent heavy rain leading to
    more compromised FFG.

    ...Southwest...
    A SLGT risk has been added for the Tucson area of Arizona after
    reviewing the latest computer guidance. A shortwave tracking
    beneath the monsoon ridge will squeeze the ridge causing briefing
    lowered heights over southern AZ, while the ridge itself expands a
    bit farther east into the Four Corners and Central High Plains.
    This will allow for some increased coverage of convection on
    Monday, despite somewhat limited coverage of instability exceeding
    500 J/kg. However, for southern AZ, a plume of PWs exceeding +1.5
    sigma will work together with MUCAPE as high as 2000 J/kg and a
    pocket of enhanced bulk shear of 25-35 kts to organize
    thunderstorms with hourly rainfall reaching or exceeding 1.5"
    (HREF/REFS/UA WRF). This rain falling top low FFG will be
    sufficient to cause scattered flash flooding in southern Arizona
    despite modest storm motions, and both the HREF and REFS FFG
    exceedance reach 25-40%. The inherited MRGL risk surrounding this
    SLGT was also adjusted slightly and expanded a bit to the
    northeast.

    ...Northern Plains...
    Potent shortwave tracking from Montana to Minnesota Monday will
    drag a wave of low pressure and its associated cold front across
    the region. Downstream of this front, 850mb inflow will back to
    become more southerly within the warm sector and surge to above 30
    kts, drawing robust PWs and MUCAPE northward to supply
    thermodynamics favorable for heavy rainfall. As thunderstorms
    develop along the front, and within the locally enhanced ascent in
    the vicinity of the low pressure, they will likely organize into
    clusters or supercells thanks to impressive bulk shear exceeding 60
    kts, and these cells will then repeat along the front. With rain
    rates possibly (10-15% chance) reaching 2"/hr, this
    training/repeating could produce as much as 3-4" of rain, leading
    to FFG exceedance reaching 5-25% from the HREF/REFS.

    Weiss


    Day 3
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    A SLGT risk was added for Tuesday for parts of southeast Arizona
    near Tucson, AZ. This is due to another day with shortwave energy
    rotating around the base of the ridge to briefly suppress it and
    cause lowered heights. The combination of this locally intense
    ascent into favorable thermodynamics will again result in scattered
    to widespread thunderstorms, with some organization possible
    through 25-35 kts of bulk shear. Storm coverage may not be as
    significant Tuesday as expected Monday (possibly due to lingering
    CINH/clouds), but slow storm motions and heavy rain rates above
    1"/hr will produce at least a local flash flood risk over
    vulnerable terrain features and burn scars from southern CO through
    southern AZ, with the greatest concentration across the TWC CWA
    prompting the new SLGT risk area.

    ...Southern/Central Appalachians into the Mid-Atlantic States...
    Cool air aloft along with ample moisture and instability could lead
    to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    There is some overlap with areas that had rainfall during the Day 1
    and 2 period, thus maintaining soil sensitivity for potential
    flooding issues, and the updated ERO features just some small
    cosmetic adjustments from the inherited MRGL risk area.

    ...Central Plains into the Upper Midwest..
    A slow moving cold front dropping into the Central Plains and
    extending into the Upper Midwest will be a focus for convective
    development on Tuesday. As this front drops southeast, it will
    become embedded in flattened and diffluent mid- level flow on the
    eastern edge of the mid-level ridge, causing it to stall as 850mb
    inflow increases to 20-30 kts pushing PWs to as high as 1.75 inches
    along it. Mean winds parallel to this front and a shortwave
    tracking along it will help to spawn training thunderstorms with
    rainfall rates of 1+"/hr, leading to a narrow corridor of as much
    as 3" of rain which may result with instances of flash flooding.

    Weiss/Campbell


    Day 4 and Day 5

    Valid 12Z Wed Aug 05 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MIDWEST...

    ...Mid to Upper Mississippi Valley/Mid West...
    There is fairly good model qpf agreement on heavy precip potential
    along and ahead of the cold front sinking southeastward Wednesday
    from the Upper MS Valley/Upper Lakes region. Favorable right
    entrance region jet dynamics along the southern edge of the
    Westerlies should enhance divergence aloft/upward vertical motion
    in an axis of 1.75"+ PW values in the vicinity of this front.
    Hourly rain amounts to 2.5" should be possible. There is a good
    chance of organized convection along and ahead of the front
    Wednesday night into the early hours of Thursday, with potential
    for localized runoff issues. The slight risk area was drawn to
    encompass the model qpf axis consensus from southern IA/far
    northern MO, eastward into northern IL/far southern WI, including
    the Chicago metro area. Only small tweaks were made based on the
    12z guidance.

    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday/Thursday night,
    maintaining reasonable continuity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    mid to late week should devolve into a shear line. An axis of high
    PW values...1.5-1.75"+, will remain across much of the eastern
    U.S. This will support additional widespread scattered showers in
    this high PW axis, with locally heavy rains and runoff issues
    possible. Hourly rain amounts to 2.5" should be possible within
    this air mass. A Marginal Risk was continued mid to late week
    across the Southern to Central Appalachians into the northern Mid-
    Atlantic, with some northeast extension made based on broader model
    spread in the heavy rainfall pattern introduced by the 12z GFS
    guidance. After several days of locally heavy rains during the
    short range period, FFG values will likely be lower/soils should
    see some level of saturation through the Southern to Central
    Appalachians into the Northern Mid Atlantic. This may warrant a
    higher risk level across these regions with future updates,
    whenever model spread narrows.

    ...Southwest/Southern High Plains...
    For mid to late week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection.
    While there is continued low confidence with details, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6V8oeJYLgkVNs935kLkg6aBOI8CnNthz_k6eJmjQHEcOXXvrxhW5pMd7mjcQJoNl7ZCmjh3Qb5B6AOYTfPv-fQBYhw0$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6V8oeJYLgkVNs935kLkg6aBOI8CnNthz_k6eJmjQHEcOXXvrxhW5pMd7mjcQJoNl7ZCmjh3Qb5B6AOYTfPv-9gcI1uE$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6V8oeJYLgkVNs935kLkg6aBOI8CnNthz_k6eJmjQHEcOXXvrxhW5pMd7mjcQJoNl7ZCmjh3Qb5B6AOYTfPv-aV2sTkU$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 2 23:57:12 2026
    FOUS30 KWBC 022356
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    756 PM EDT Sun Aug 2 2026

    Day 1
    Valid 01Z Mon Aug 03 2026 - 12Z Mon Aug 03 2026

    ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR NORTHERN FLORIDA
    & THE MID-ATLANTIC STATES...


    ...East Coast States...
    Anomalous upper low continues to plague the eastern portions of
    the CONUS with broad and impressive synoptic ascent impinging into
    significant thermodynamics. This will provide an environment
    favorable for heavy rainfall within convection almost anywhere from
    Florida to Upstate NY. A few focused areas of heavier rainfall and
    greater flash flood potential exist.

    The Florida Panhandle and into the Big Bend have seen some
    saturation from heavy rainfall on Saturday. Pronounced onshore
    flow from the Gulf draws impressive PWs/CAPE onshore ahead of a
    cold front will again result in a nocturnal batch of thunderstorms
    with 2-3"/hour amounts with local totals to 6" possible. This
    heavy rain will likely lead to rapid runoff and instances of flash
    flooding, particularly over clay hills in the region, so the
    inherited SLGT (and enhanced SLGT) was only cosmetically adjusted.

    Farther north across the northern Mid-Atlantic, the combination of
    a TROWAL/deformation axis and vulnerable soils has created a more
    robust excessive rainfall risk. While SBCAPE into the Great Lakes
    may be somewhat more limited, the theta-e ridge rotating into a
    TROWAL will sufficiently enhanced instability to support 1+"/hr
    rain rates with slow/backbuilding motions. This will support a
    stripe of 3-5" of rain into far northern Upstate NY, where the SLGT
    risk continues. The Slight Risk has been expanded eastward to deal
    with ongoing convection and the signal seen in the 18z HREF/12z
    REFS guidance. Some of this area, particularly northern NJ and
    southeast NY, is more vulnerable to flash flooding or seen heavy
    rains during the past week.

    Finally, A SLGT risk exists for extreme coastal NC where a coastal
    band of heavy rain may develop or move into the region from SC.
    The mesoscale guidance is coastal with the signal from SC across
    NC. Hourly rain amounts to 2.5" are possible here, with higher
    totals where cells train. Most of this area has been dry outside
    of far eastern NC and the Outer Banks, and 3-hr FFG is generally
    3-4" which has only a very minor threat of exceedance from the
    HREF. Due to the potential for training, left the SLGT in place
    but made some minor cosmetic adjustments.


    ...South Texas...
    A cold front dropping into South Texas is the focus for slow moving thunderstorms. The mesoscale guidance is not extremely excited
    with this event, but South TX can surprise. Hourly rain amounts of
    2"/hr are likely at times, which despite a slow southern advance,
    could produce total 4" of rain and isolated flash flooding. This
    area was adjusted southward in concert with recent radar
    reflectivity trends and the 18z HREF/12z REFS guidance.


    ..Southwest...
    Convection has been developing somewhat across the Southwest as of
    late. The ingredients available would allow for hourly rain amounts
    to exceed 1"/hr at times, especially in the presence of enhanced
    25-35 kts shear which could organize cells into clusters across the
    area. The region is less expansive than earlier based upon recent radar reflectivity trends and the 18z HREF/12z REFS guidance.

    Roth


    Day 2
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE TRI-STATE
    AREA OF NEW YORK, NEW JERSEY, AND CONNECTICUT, AS WELL AS FOR THE COASTAL CAROLINAS, THE BIG BEND OF FLORIDA, AND FAR SOUTHERN ARIZONA...

    ...East Coast...
    The anomalous upper trough plaguing the eastern 1/3 of the CONUS
    will persist on Monday, but with a different evolution. A
    shortwave trough rotating through the longwave feature will help
    close off a mid-level low center over northern GA, driving subtle
    height rises to its north, but with subtle impulses continuing to
    rotate cyclonically around it. At the same time, a jet streak
    pivoting into New England will intensify as it arcs
    poleward, leaving its favorable RRQ for ascent over the Mid- Atlantic/Northeast. Together, this again creates broad deep layer
    ascent along most of the East Coast, acting upon robust
    thermodynamics to create widespread thunderstorms with heavy rain
    rates.

    While once again the forcing will be somewhat diffuse and broad,
    leading to widespread scattered convection as reflected by most of
    the available high-res CAMs. Locally enhanced ascent along a slow eastward-advancing cold front will help organize some convection
    along it. This convergence combined with bulk shear of 20-25 kts
    will lead to clusters/multi-cells that will train thanks to
    boundary-parallel mean flow to lengthen the duration of heavy rain
    rates. With both HREF and REFS probabilities indicating a 30-60% of
    1"/hr or more rates, where any convection can organize or train,
    this could produce 3-5" of rain.

    The most likely locations for this heavier rainfall are across the
    Tri-State area of CT/NY/NJ, and down towards Philadelphia, extreme
    eastern North Carolina, and the Florida Big Bend region. Inherited
    SLGT risks across these focused areas remain both due to the
    potential organized convection on Monday, but also since all three
    have already vulnerable soils due to recent heavy rain leading to
    more compromised FFG.

    ...Southwest...
    A SLGT risk has been added for the Tucson area of Arizona after
    reviewing the latest computer guidance. A shortwave tracking
    beneath the monsoon ridge will squeeze the ridge causing briefing
    lowered heights over southern AZ, while the ridge itself expands a
    bit farther east into the Four Corners and Central High Plains.
    This will allow for some increased coverage of convection on
    Monday, despite somewhat limited coverage of instability exceeding
    500 J/kg. However, for southern AZ, a plume of PWs exceeding +1.5
    sigma will work together with MUCAPE as high as 2000 J/kg and a
    pocket of enhanced bulk shear of 25-35 kts to organize
    thunderstorms with hourly rainfall reaching or exceeding 1.5"
    (HREF/REFS/UA WRF). This rain falling top low FFG will be
    sufficient to cause scattered flash flooding in southern Arizona
    despite modest storm motions, and both the HREF and REFS FFG
    exceedance reach 25-40%. The inherited MRGL risk surrounding this
    SLGT was also adjusted slightly and expanded a bit to the
    northeast.

    ...Northern Plains...
    Potent shortwave tracking from Montana to Minnesota Monday will
    drag a wave of low pressure and its associated cold front across
    the region. Downstream of this front, 850mb inflow will back to
    become more southerly within the warm sector and surge to above 30
    kts, drawing robust PWs and MUCAPE northward to supply
    thermodynamics favorable for heavy rainfall. As thunderstorms
    develop along the front, and within the locally enhanced ascent in
    the vicinity of the low pressure, they will likely organize into
    clusters or supercells thanks to impressive bulk shear exceeding 60
    kts, and these cells will then repeat along the front. With rain
    rates possibly (10-15% chance) reaching 2"/hr, this
    training/repeating could produce as much as 3-4" of rain, leading
    to FFG exceedance reaching 5-25% from the HREF/REFS.

    Weiss


    Day 3
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    A SLGT risk was added for Tuesday for parts of southeast Arizona
    near Tucson, AZ. This is due to another day with shortwave energy
    rotating around the base of the ridge to briefly suppress it and
    cause lowered heights. The combination of this locally intense
    ascent into favorable thermodynamics will again result in scattered
    to widespread thunderstorms, with some organization possible
    through 25-35 kts of bulk shear. Storm coverage may not be as
    significant Tuesday as expected Monday (possibly due to lingering
    CINH/clouds), but slow storm motions and heavy rain rates above
    1"/hr will produce at least a local flash flood risk over
    vulnerable terrain features and burn scars from southern CO through
    southern AZ, with the greatest concentration across the TWC CWA
    prompting the new SLGT risk area.

    ...Southern/Central Appalachians into the Mid-Atlantic States...
    Cool air aloft along with ample moisture and instability could lead
    to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    There is some overlap with areas that had rainfall during the Day 1
    and 2 period, thus maintaining soil sensitivity for potential
    flooding issues, and the updated ERO features just some small
    cosmetic adjustments from the inherited MRGL risk area.

    ...Central Plains into the Upper Midwest..
    A slow moving cold front dropping into the Central Plains and
    extending into the Upper Midwest will be a focus for convective
    development on Tuesday. As this front drops southeast, it will
    become embedded in flattened and diffluent mid- level flow on the
    eastern edge of the mid-level ridge, causing it to stall as 850mb
    inflow increases to 20-30 kts pushing PWs to as high as 1.75 inches
    along it. Mean winds parallel to this front and a shortwave
    tracking along it will help to spawn training thunderstorms with
    rainfall rates of 1+"/hr, leading to a narrow corridor of as much
    as 3" of rain which may result with instances of flash flooding.

    Weiss/Campbell


    Day 4 and Day 5

    Valid 12Z Wed Aug 05 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MIDWEST...

    ...Mid to Upper Mississippi Valley/Mid West...
    There is fairly good model agreement on heavy precip potential
    along and ahead of the cold front sinking southeastward Wednesday
    from the Upper MS Valley/Upper Lakes region. Favorable right
    entrance region jet dynamics along the southern edge of the
    Westerlies should enhance divergence aloft/upward vertical motion
    in an axis of 1.75"+ PW values in the vicinity of this front.
    Hourly rain amounts to 2.5" should be possible. There is a good
    chance of organized convection along and ahead of the front
    Wednesday night into the early hours of Thursday, with potential
    for localized runoff issues. The slight risk area was drawn to
    encompass the model qpf axis consensus from southern IA/far
    northern MO, eastward into northern IL/far southern WI, including
    the Chicago metro area. Only small tweaks were made based on the
    12z guidance.

    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday/Thursday night,
    maintaining reasonable continuity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    mid to late week should devolve into a shear line. An axis of high
    PW values...1.5-1.75"+, will remain across much of the eastern
    U.S. This will support additional widespread scattered showers in
    this high PW axis, with locally heavy rains and runoff issues
    possible. Hourly rain amounts to 2.5" should be possible within
    this air mass. A Marginal Risk was continued mid to late week
    across the Southern to Central Appalachians into the northern Mid-
    Atlantic, with some northeast extension made based on broader model
    spread in the heavy rainfall pattern introduced by the 12z GFS
    guidance. After several days of locally heavy rains during the
    short range period, FFG values will likely be lower/soils should
    see some level of saturation through the Southern to Central
    Appalachians into the Northern Mid Atlantic. This may warrant a
    higher risk level across these regions with future updates,
    whenever model spread narrows.

    ...Southwest/Southern High Plains...
    For mid to late week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection.
    While there is continued low confidence with details, but locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!755Jt6q_KJB9KGrIuZ6o86l9T_JTmm3BcxblIPvch9_cRd9sdHX2jT7hhSHf2zaFaAVrtyx0qXiRhIPMY2-sDg42maA$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!755Jt6q_KJB9KGrIuZ6o86l9T_JTmm3BcxblIPvch9_cRd9sdHX2jT7hhSHf2zaFaAVrtyx0qXiRhIPMY2-sANSTe-0$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!755Jt6q_KJB9KGrIuZ6o86l9T_JTmm3BcxblIPvch9_cRd9sdHX2jT7hhSHf2zaFaAVrtyx0qXiRhIPMY2-s9syTUDM$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 3 08:10:18 2026
    FOUS30 KWBC 030809
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    409 AM EDT Mon Aug 3 2026

    Day 1
    Valid 12Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NEW JERSEY TO MASSACHUSETTS, FOR THE COASTAL CAROLINAS, THE BIG BEND OF FLORIDA,
    AND FAR SOUTHERN ARIZONA...

    ...East Coast...

    A shortwave trough rotating through the longwave feature will help
    close off a mid-level low center over northern GA, driving subtle
    height rises to its north, but with subtle impulses continuing to
    rotate cyclonically around it. Meanwhile, a jet streak pivoting
    into New England will intensify as it arcs poleward, leaving its
    favorable RRQ for ascent over the Mid- Atlantic/Northeast. This
    setup supports broad deep layer ascent that will help trigger
    widespread convection capable of heavy rainfall intensities. The
    slow nature of the front will help organize some convection along
    it. This convergence combined with bulk shear of 20-25 kts will
    lead to clusters/multi- cells that will train thanks to boundary-
    parallel mean flow to lengthen the duration of heavy rain rates.
    With both HREF and REFS probabilities indicating a 30-60% of 1"/hr
    or more rates, where any convection can organize or train, this
    could produce 3-5" of rain. The most likely locations for this
    heavier rainfall will be from southern New Jersey to central
    Massachusetts, which is where the Slight Risk was maintained.

    ...Southwest...

    A shortwave tracking beneath the monsoon ridge will squeeze the
    ridge causing briefing lowered heights over southern Arizona,
    while the ridge itself expands a bit farther east into the Four
    Corners and Central High Plains. Although instability will be
    somewhat limited across the region, the areal coverage of
    convection will be increased for this period. Higher concentration
    of heavy rainfall is expected to focus over southern Arizona where
    a plume of PWs exceeding +1.5 sigma will work together with MUCAPE
    as high as 2000 J/kg and a pocket of enhanced bulk shear of 25-35
    kts to organize thunderstorms with hourly rainfall reaching or
    exceeding 1.5" (HREF/REFS/UA WRF). A Slight Risk was maintained for
    southern Arizona with a Marginal Risk covers southern and central
    portions of Arizona and New Mexico.

    ...Northern Plains...

    Showers and thunderstorms are expected to fire up across the
    Northern Plains as a potent shortwave tracking from Montana to
    Minnesota drags a wave of low pressure and its associated cold
    front across the region. A steady stream of moisture will be drawn
    northward ahead of the approaching system and will aid in the
    enhance of rainfall. Hourly rain rates have the potential (10-15%
    chance) to reach 2"/hr, this training/repeating could produce as
    much as 3-4" of rain, leading to FFG exceedance reaching 5-25% from
    the HREF/REFS. A Marginal Risk covers the eastern Dakotas and
    northern half of Minnesota.

    Campbell/Weiss


    Day 2
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...

    Shortwave energy rotating around the base of the ridge will briefly suppress
    it and cause lowered heights. The combination of this locally
    intense ascent into favorable thermodynamics will again result in
    scattered to widespread thunderstorms, with some organization
    possible through 25-35 kts of bulk shear. Slow storm motions and
    heavy rain rates above 1"/hr will produce at least a local flash
    flood risk over vulnerable terrain features and burn scars from
    southern Colorado through southern Arizona, with the greatest
    concentration across south-southeast Arizona with a Slight Risk
    area was maintained for this period.

    ...Southern/Central Appalachians into the Mid-Atlantic States...

    Cool air aloft along with ample moisture and instability could lead
    to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    Recent rain will keep soils sensitive for potential flooding
    issues. The Marginal Risk area was maintained across the eastern
    Tennessee Valley/Southern Appalachians to the Mid-Atlantic
    coastline.

    ...Central Plains into the Upper Midwest...

    Showers and thunderstorms will fire up along and ahead of a slow
    moving cold front sinking southward into the Central Plains and
    extending into the Upper Midwest. PW values up to 1.75 inches will
    be drawn into the system. Mean winds parallel to this front and a
    shortwave tracking along it will help to spawn training
    thunderstorms with rainfall rates of 1+"/hr, leading to a narrow
    corridor of as much as 3" of rain which may result with instances
    of flash flooding.

    Campbell/Weiss


    Day 3
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MIDWEST...

    ...Mid to Upper Mississippi Valley/Mid West...

    Heavy rainfall will continue to spread along and ahead of the
    cold front sinking southeastward from the Upper MS Valley/Upper
    Lakes region. The presence of a strong upper level jet within the
    right entrance region will foster local enhancement of rainfall
    rates potentially up to 2.5 inches/hour in proximity to the
    boundary. The latest guidance continue to focus the highest axis of
    QPF southeast Nebraska to southern Wisconsin/ eastward into
    northern IL including the Chicago metro area.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    mid to late week should devolve into a shear line. An axis of high
    PW values...1.5-1.75"+, will remain across much of the eastern
    U.S. High PW values will continue to transport northward into the
    region which will support locally heavy rain, with potential for
    hourly rates reaching 2.5 inches/hour. A Marginal Risk area was
    maintained across the Southern to Central Appalachians into the
    northern Mid-Atlantic for this period. Much of this region will be
    sensitive given multiple days of rainfall and lowered FFG values.

    ...Southwest/Southern High Plains...

    A Marginal Risk was maintained to cover persistent monsoonal
    activity across the Southwest and Southern Rockies where heavy
    rain and isolated runoff issues in the above average PW values are
    expected.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Thu Aug 06 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST, EAST NORTHEASTWARD THROUGH THE CENTRAL/SOUTHERN PLAINS,
    MID MS VALLEY, OH VALLEY, NORTHERN MID ATLANTIC AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday night/early
    Friday morning.

    ...Lower Lakes, OH Valley into the Northern Mid Atlantic...
    A slow moving frontal boundary expected to persist across the
    Lower Lakes into the Northeast both day 4 and 5. Shortwave energy
    expected to push east both day 4 and 5 along the southern edge of
    the westerlies across these regions, helping to accentuate lift in
    the high PW axis in the vicinity of this front. There is fairly
    good model qpf agreement on moderate to locally heavy precip totals
    across these areas, supporting isolated runoff issues.

    ...Southern to Central Appalachians...
    For both day 4 and day 5, a broad marginal risk is depicted
    through the Central to Southern Appalachians for widespread
    scattered convection. Not a lot of confidence in qpf details, but
    with PW values expected to remain in the 1.5-1.75"+ range, locally
    heavy rains and runoff issues possible.

    ...Southwest/Southern High Plains...
    For mid to late week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection.
    While there is continued low confidence with qpf details, locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_HfnFUhyKRyhlq4lbYCnPhDgh6gn1lE-cmOJpv78ZWrw3eh0e6KoPe30rpWDDWODBKYagnT0JUja6TJiAh_M6kq80I0$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_HfnFUhyKRyhlq4lbYCnPhDgh6gn1lE-cmOJpv78ZWrw3eh0e6KoPe30rpWDDWODBKYagnT0JUja6TJiAh_MBnYrBm4$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_HfnFUhyKRyhlq4lbYCnPhDgh6gn1lE-cmOJpv78ZWrw3eh0e6KoPe30rpWDDWODBKYagnT0JUja6TJiAh_MoV6-gB8$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 3 15:51:52 2026
    FOUS30 KWBC 031551
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1151 AM EDT Mon Aug 3 2026

    Day 1
    Valid 16Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NEW JERSEY TO MASSACHUSETTS, BIG BEND OF FLORIDA, AND FAR SOUTHERN ARIZONA...

    ...16Z Update...

    The primary change to this ERO issuance was to remove the Slight
    Risk from the coastal Carolinas. Current activity is mainly
    offshore, and potential upcoming afternoon activity and another
    round tonight seem modest enough to be considered Marginal.
    Probabilities for QPF greater than 2" have been dropping. The
    Slight Risk over portions of Florida seems reasonable with ongoing
    convection over the next few hours before ending by this evening,
    as does the Slight in the Northeast (see MPD 933 for more). The
    monsoonal convection with a particular focus over southeast Arizona
    still looks good in the new CAMs, while the north-central U.S.
    Marginal was adjusted somewhat to account for new guidance. Rain is
    ongoing in the north-central U.S., which could wet soils before a
    possibly stronger convective round this evening and tonight. See
    the previous discussion below for more on the meteorological setup.

    Tate

    ...Previous Discussion...

    ...East Coast...

    A shortwave trough rotating through the longwave feature will help
    close off a mid-level low center over northern GA, driving subtle
    height rises to its north, but with subtle impulses continuing to
    rotate cyclonically around it. Meanwhile, a jet streak pivoting
    into New England will intensify as it arcs poleward, leaving its
    favorable RRQ for ascent over the Mid- Atlantic/Northeast. This
    setup supports broad deep layer ascent that will help trigger
    widespread convection capable of heavy rainfall intensities. The
    slow nature of the front will help organize some convection along
    it. This convergence combined with bulk shear of 20-25 kts will
    lead to clusters/multi- cells that will train thanks to boundary-
    parallel mean flow to lengthen the duration of heavy rain rates.
    With both HREF and REFS probabilities indicating a 30-60% of 1"/hr
    or more rates, where any convection can organize or train, this
    could produce 3-5" of rain. The most likely locations for this
    heavier rainfall will be from southern New Jersey to central
    Massachusetts, which is where the Slight Risk was maintained.

    ...Southwest...

    A shortwave tracking beneath the monsoon ridge will squeeze the
    ridge causing briefing lowered heights over southern Arizona,
    while the ridge itself expands a bit farther east into the Four
    Corners and Central High Plains. Although instability will be
    somewhat limited across the region, the areal coverage of
    convection will be increased for this period. Higher concentration
    of heavy rainfall is expected to focus over southern Arizona where
    a plume of PWs exceeding +1.5 sigma will work together with MUCAPE
    as high as 2000 J/kg and a pocket of enhanced bulk shear of 25-35
    kts to organize thunderstorms with hourly rainfall reaching or
    exceeding 1.5" (HREF/REFS/UA WRF). A Slight Risk was maintained for
    southern Arizona with a Marginal Risk covers southern and central
    portions of Arizona and New Mexico.

    ...Northern Plains...

    Showers and thunderstorms are expected to fire up across the
    Northern Plains as a potent shortwave tracking from Montana to
    Minnesota drags a wave of low pressure and its associated cold
    front across the region. A steady stream of moisture will be drawn
    northward ahead of the approaching system and will aid in the
    enhance of rainfall. Hourly rain rates have the potential (10-15%
    chance) to reach 2"/hr, this training/repeating could produce as
    much as 3-4" of rain, leading to FFG exceedance reaching 5-25% from
    the HREF/REFS. A Marginal Risk covers the eastern Dakotas and
    northern half of Minnesota.

    Campbell/Weiss


    Day 2
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...

    Shortwave energy rotating around the base of the ridge will briefly suppress
    it and cause lowered heights. The combination of this locally
    intense ascent into favorable thermodynamics will again result in
    scattered to widespread thunderstorms, with some organization
    possible through 25-35 kts of bulk shear. Slow storm motions and
    heavy rain rates above 1"/hr will produce at least a local flash
    flood risk over vulnerable terrain features and burn scars from
    southern Colorado through southern Arizona, with the greatest
    concentration across south-southeast Arizona with a Slight Risk
    area was maintained for this period.

    ...Southern/Central Appalachians into the Mid-Atlantic States...

    Cool air aloft along with ample moisture and instability could lead
    to hourly rain amounts up to 2.5 inches, which would be
    problematic in rugged terrain, sensitive soils, and urban areas.
    Recent rain will keep soils sensitive for potential flooding
    issues. The Marginal Risk area was maintained across the eastern
    Tennessee Valley/Southern Appalachians to the Mid-Atlantic
    coastline.

    ...Central Plains into the Upper Midwest...

    Showers and thunderstorms will fire up along and ahead of a slow
    moving cold front sinking southward into the Central Plains and
    extending into the Upper Midwest. PW values up to 1.75 inches will
    be drawn into the system. Mean winds parallel to this front and a
    shortwave tracking along it will help to spawn training
    thunderstorms with rainfall rates of 1+"/hr, leading to a narrow
    corridor of as much as 3" of rain which may result with instances
    of flash flooding.

    Campbell/Weiss


    Day 3
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID TO UPPER MISSISSIPPI VALLEY/MIDWEST...

    ...Mid to Upper Mississippi Valley/Mid West...

    Heavy rainfall will continue to spread along and ahead of the
    cold front sinking southeastward from the Upper MS Valley/Upper
    Lakes region. The presence of a strong upper level jet within the
    right entrance region will foster local enhancement of rainfall
    rates potentially up to 2.5 inches/hour in proximity to the
    boundary. The latest guidance continue to focus the highest axis of
    QPF southeast Nebraska to southern Wisconsin/ eastward into
    northern IL including the Chicago metro area.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    mid to late week should devolve into a shear line. An axis of high
    PW values...1.5-1.75"+, will remain across much of the eastern
    U.S. High PW values will continue to transport northward into the
    region which will support locally heavy rain, with potential for
    hourly rates reaching 2.5 inches/hour. A Marginal Risk area was
    maintained across the Southern to Central Appalachians into the
    northern Mid-Atlantic for this period. Much of this region will be
    sensitive given multiple days of rainfall and lowered FFG values.

    ...Southwest/Southern High Plains...

    A Marginal Risk was maintained to cover persistent monsoonal
    activity across the Southwest and Southern Rockies where heavy
    rain and isolated runoff issues in the above average PW values are
    expected.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Thu Aug 06 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST, EAST NORTHEASTWARD THROUGH THE CENTRAL/SOUTHERN PLAINS,
    MID MS VALLEY, OH VALLEY, NORTHERN MID ATLANTIC AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday night/early
    Friday morning.

    ...Lower Lakes, OH Valley into the Northern Mid Atlantic...
    A slow moving frontal boundary expected to persist across the
    Lower Lakes into the Northeast both day 4 and 5. Shortwave energy
    expected to push east both day 4 and 5 along the southern edge of
    the westerlies across these regions, helping to accentuate lift in
    the high PW axis in the vicinity of this front. There is fairly
    good model qpf agreement on moderate to locally heavy precip totals
    across these areas, supporting isolated runoff issues.

    ...Southern to Central Appalachians...
    For both day 4 and day 5, a broad marginal risk is depicted
    through the Central to Southern Appalachians for widespread
    scattered convection. Not a lot of confidence in qpf details, but
    with PW values expected to remain in the 1.5-1.75"+ range, locally
    heavy rains and runoff issues possible.

    ...Southwest/Southern High Plains...
    For mid to late week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection.
    While there is continued low confidence with qpf details, locally
    heavy rains and isolated runoff issues possible in the above
    average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!-eEiQnYRVn4hkcfxhZq3ibTKC7Dtr1FkJHKHdcQz2QgNehhhIZcds8gaICNQqz-GSc2KHM4gNvICj3XUC9m1gJNrEjQ$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!-eEiQnYRVn4hkcfxhZq3ibTKC7Dtr1FkJHKHdcQz2QgNehhhIZcds8gaICNQqz-GSc2KHM4gNvICj3XUC9m1ZReHRQU$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!-eEiQnYRVn4hkcfxhZq3ibTKC7Dtr1FkJHKHdcQz2QgNehhhIZcds8gaICNQqz-GSc2KHM4gNvICj3XUC9m1KVSPNGA$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 3 19:36:26 2026
    FOUS30 KWBC 031936
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    336 PM EDT Mon Aug 3 2026

    Day 1
    Valid 16Z Mon Aug 03 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NEW JERSEY TO MASSACHUSETTS, BIG BEND OF FLORIDA, AND FAR SOUTHERN ARIZONA...

    ...16Z Update...

    The primary change to this ERO issuance was to remove the Slight
    Risk from the coastal Carolinas. Current activity is mainly
    offshore, and potential upcoming afternoon activity and another
    round tonight seem modest enough to be considered Marginal.
    Probabilities for QPF greater than 2" have been dropping. The
    Slight Risk over portions of Florida seems reasonable with ongoing
    convection over the next few hours before ending by this evening,
    as does the Slight in the Northeast (see MPD 933 for more). The
    monsoonal convection with a particular focus over southeast Arizona
    still looks good in the new CAMs, while the north-central U.S.
    Marginal was adjusted somewhat to account for new guidance. Rain is
    ongoing in the north-central U.S., which could wet soils before a
    possibly stronger convective round this evening and tonight. See
    the previous discussion below for more on the meteorological setup.

    Tate

    ...Previous Discussion...

    ...East Coast...

    A shortwave trough rotating through the longwave feature will help
    close off a mid-level low center over northern GA, driving subtle
    height rises to its north, but with subtle impulses continuing to
    rotate cyclonically around it. Meanwhile, a jet streak pivoting
    into New England will intensify as it arcs poleward, leaving its
    favorable RRQ for ascent over the Mid- Atlantic/Northeast. This
    setup supports broad deep layer ascent that will help trigger
    widespread convection capable of heavy rainfall intensities. The
    slow nature of the front will help organize some convection along
    it. This convergence combined with bulk shear of 20-25 kts will
    lead to clusters/multi- cells that will train thanks to boundary-
    parallel mean flow to lengthen the duration of heavy rain rates.
    With both HREF and REFS probabilities indicating a 30-60% of 1"/hr
    or more rates, where any convection can organize or train, this
    could produce 3-5" of rain. The most likely locations for this
    heavier rainfall will be from southern New Jersey to central
    Massachusetts, which is where the Slight Risk was maintained.

    ...Southwest...

    A shortwave tracking beneath the monsoon ridge will squeeze the
    ridge causing briefing lowered heights over southern Arizona,
    while the ridge itself expands a bit farther east into the Four
    Corners and Central High Plains. Although instability will be
    somewhat limited across the region, the areal coverage of
    convection will be increased for this period. Higher concentration
    of heavy rainfall is expected to focus over southern Arizona where
    a plume of PWs exceeding +1.5 sigma will work together with MUCAPE
    as high as 2000 J/kg and a pocket of enhanced bulk shear of 25-35
    kts to organize thunderstorms with hourly rainfall reaching or
    exceeding 1.5" (HREF/REFS/UA WRF). A Slight Risk was maintained for
    southern Arizona with a Marginal Risk covers southern and central
    portions of Arizona and New Mexico.

    ...Northern Plains...

    Showers and thunderstorms are expected to fire up across the
    Northern Plains as a potent shortwave tracking from Montana to
    Minnesota drags a wave of low pressure and its associated cold
    front across the region. A steady stream of moisture will be drawn
    northward ahead of the approaching system and will aid in the
    enhance of rainfall. Hourly rain rates have the potential (10-15%
    chance) to reach 2"/hr, this training/repeating could produce as
    much as 3-4" of rain, leading to FFG exceedance reaching 5-25% from
    the HREF/REFS. A Marginal Risk covers the eastern Dakotas and
    northern half of Minnesota.

    Campbell/Weiss


    Day 2
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...

    Weak energy aloft could undercut the broad Southwest upper ridge to
    the south and provide support for enhanced convection Tuesday. The
    peak instability of 1000-2500 J/kg MUCAPE will be in southern
    Arizona. Above average moisture transport (4+ standardized
    anomalies for 850-700 mb moisture flux from the GFS, 2+ from the
    ECMWF) will be in place as well, allowing for heavy rain rates
    above 1"/hour. CAMs including the Arizona WRF indicate slow
    moving/westward moving convection potentially yielding increased
    amounts. The Slight Risk still looks reasonable across south-
    southeast Arizona within a broader Marginal. Typical terrain
    features and burn scars will be particularly vulnerable to flash
    flooding concerns.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    An upper low will meander over the Southeast/southern Appalachians
    Tuesday, which will be somewhat weak but still provide lower
    heights than normal for early August and broadly support ascent.
    Large areas of 1000-2000 J/kg MUCAPE (locally higher) are expected
    in the southeastern U.S., while above average PWs are expected at
    least in eastern areas. Scattered convection is likely with high
    hourly rain rates, so a Marginal Risk with limited edits remains in
    effect for portions of the Southeast, Appalachians, and southern
    Mid-Atlantic. Pockets of wet antecedent conditions could exacerbate
    flooding concerns, while rugged terrain and urban areas are also
    vulnerable. Florida should also see enhanced instability and
    moisture, but the greatest rain totals look to be across the
    Everglades, not a sensitive region for flooding.

    ...Central Plains into the Upper Midwest...

    A reasonably strong trough coming through the north-central U.S.
    will support a cold front slowly moving through the Midwest and
    Plains. Moisture and instability are forecast to pool along this
    cold front while the right entrance region of the jet provides
    ascent for rain/thunderstorms. The front should lay out a bit west-
    east by Tuesday evening/night and lead to a corridor of training
    convection. CAMs show axes of 3" totals with some minor spread in
    placement. Antecedent conditions are on the dry side in most areas,
    so this still looks like only a Marginal threat for flash flooding
    through Tuesday, but will continue to monitor trends for higher
    totals and agreement on the axis of heaviest totals for any
    potential Slight upgrade. Trimmed out the western area of the
    Marginal from the previous forecast due to less rain focusing there
    and falling over the Nebraska Sandhills.

    Tate


    Day 3
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    ...Central Plains to Mid/Upper Mississippi Valley...

    By Wednesday, the upper trough and front described in the Day 2
    discussion will further slow down and provide an axis for moisture
    to pool and thunderstorms to be persistent. Particularly given some
    potential overlap with rain the previous day affecting antecedent
    conditions, will continue to indicate a Slight Risk. There has been
    more model spread in the position of heaviest rain by Wednesday.
    While thunderstorms should be active all along the front through
    the Midwest back toward the central Plains, some guidance like the
    EC-AIFS and AIGFS are indicating the central Plains to Mid-
    Mississippi Valley should see the greatest rainfall totals.
    Expanded the Slight Risk to account for this southwestward
    potential, but maintained the Slight in the Chicago area too given
    some models (GFS/UKMET/NAM etc.) still show heavy rain over that
    area. Further shifts may happen in future cycles before models
    hopefully converge.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. This should keep
    supporting locally heavy rain in scattered thunderstorms, with high
    rain rates, so a Marginal Risk still looks good. Any areas seeing
    repeated rounds of rain from the previous couple of wet days would
    be particularly sensitive to flooding concerns. Convection may once
    again be enhanced over portions of the Florida Peninsula, but given
    a likely rainfall focus over the less sensitive areas of the
    Everglades westward, will not introduce a Marginal at this point.

    ...Southwest/Southern High Plains...

    On Wednesday, moist inflow on the southern part of the Southwest
    upper high will persist, though moisture transport anomalies seem
    to be a touch lower than the Monday/Tuesday values and with less of
    a focus for heavy rain placement. Therefore a Marginal Risk seems
    reasonable for isolated flooding and runoff issues for much of
    Arizona and New Mexico.

    Tate


    Day 4 and Day 5

    Valid 12Z Thu Aug 06 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday night/early
    Friday morning.

    ...Lower Lakes, OH Valley into the Northern Mid Atlantic...
    A slow-moving frontal boundary expected to persist late this week.
    Shortwave energy expected to push east along the southern edge of
    the Westerlies, helping to accentuate lift in the high PW axis in
    the vicinity of this front. There is fairly good model qpf
    agreement on moderate to locally heavy precip totals across these
    areas, with hourly rain amounts up to 2.5" possible, supporting
    at least isolated runoff issues in urban areas and places with some
    degree of soil saturation.

    ...Southern to Central Appalachians...
    For late this week, a broad marginal risk is depicted through the
    Central to Southern Appalachians for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, hourly rain amounts to
    2.5" could lead to runoff issues, particularly in urban areas and
    within sharp relief.

    ...Southwest/Southern High Plains...
    For late this week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection. The
    ridge placement across the southern Great Basin during the time
    frame along with some backing off in the moisture return on the
    guidance led to some reduction in the Marginal Risk area across
    southern NV. This led to less reliance on the 00z/12z ECMWF for the
    QPF breadth, which was collaborated with VEF/the Las Vegas NV
    forecast office. While there is continued low confidence with
    details, locally heavy rains with hourly amounts up to 2" could
    lead to isolated runoff issues.

    Roth/Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!9xZUoSkq99AE8qte7SzfyZYwnBPnmgMGMP7kyLvdPOEqt2ZXtCkjiOX2s3bDzA5VawP3URnSj76Nt1Q2Q8sqCKLsBf4$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!9xZUoSkq99AE8qte7SzfyZYwnBPnmgMGMP7kyLvdPOEqt2ZXtCkjiOX2s3bDzA5VawP3URnSj76Nt1Q2Q8sqSxT91wk$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!9xZUoSkq99AE8qte7SzfyZYwnBPnmgMGMP7kyLvdPOEqt2ZXtCkjiOX2s3bDzA5VawP3URnSj76Nt1Q2Q8sqYwG5DHc$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 4 00:03:12 2026
    FOUS30 KWBC 040002
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    802 PM EDT Mon Aug 3 2026

    Day 1
    Valid 01Z Tue Aug 04 2026 - 12Z Tue Aug 04 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE SOUTHEAST AND FAR SOUTHEAST ARIZONA...

    ...In and near the Southeast...
    A deep layer low forms across GA this evening into tonight,
    backing the low level flow along the Southeast coast more ashore
    which is expected to bring instability back into the equation
    tonight. It also keeps onshore flow from Tampa Bay north across the
    FL Big Bend, keeping instability around overnight. Other activity
    from northwest Cuba is sending outflow boundaries out to the Keys
    causing some new development across portions of Florida Bay/the
    southeast Gulf and FL Straits. Where cells merge and/or train,
    hourly rain amounts to 3" are possible. Based on the 18z HREF/12z
    REFS, shifted the Slight Risk in FL somewhat southward and
    broadened it a little. They also led to a reintroduction of the
    Slight Risk along the coast of the Carolinas, which saw skirmishes
    of heavy rain this afternoon and early evening which is forecast to
    continue overnight.


    ...Southwest...
    Showers and thunderstorms have become confined to southwest NM and
    eastern AZ as of late. Both the 18z HREF/12z REFS indicate that the
    previously drawn Slight Risk still has merit until 03-05z before
    activity either fades or shifts southwest into northwest Mexico.
    Hourly rain amounts to 2" remain possible in the meantime wherever
    cells merge or train.


    ...Northern Plains...
    Showers and thunderstorms are beginning to fire up across northwest
    MN as a potent shortwave approaches, dragging a wave of low
    pressure and its associated cold front across the region. A steady
    stream of moisture has been drawn northward ahead of the
    approaching system and will aid in the enhance of rainfall. Hourly
    rain rates have the potential (10-15% chance) to reach 2"/hr, this training/repeating could produce as much as 3-4" of rain, leading
    to FFG exceedance reaching 5-25% from the HREF/REFS. A Marginal
    Risk covers the eastern Dakotas, Minnesota, and northern NE which
    is supported by the 18z HREF/12z REFS and radar reflectivity trends
    as of the time of this discussion's writing.

    Roth


    Day 2
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection Tuesday.
    The peak instability of 1000-2500 J/kg MUCAPE will be in southern
    Arizona. Above average moisture transport (4+ standardized
    anomalies for 850-700 mb moisture flux from the GFS, 2+ from the
    ECMWF) will be in place as well, allowing for heavy rain rates
    above 1"/hour. CAMs including the Arizona WRF indicate slow
    moving/westward moving convection potentially yielding increased
    amounts. The Slight Risk still looks reasonable across south-
    southeast Arizona within a broader Marginal. Typical terrain
    features and burn scars will be particularly vulnerable to flash
    flooding concerns.


    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...
    An upper low will meander over the Southeast/southern Appalachians
    Tuesday, which will be somewhat weak but still provide lower
    heights than normal for early August and broadly support ascent.
    Large areas of 1000-2000 J/kg MUCAPE (locally higher) are expected
    in the southeastern U.S., while above average PWs are expected at
    least in eastern areas. Scattered convection is likely with high
    hourly rain rates, so a Marginal Risk with limited edits remains in
    effect for portions of the Southeast, Appalachians, and southern
    Mid-Atlantic. Pockets of wet antecedent conditions could exacerbate
    flooding concerns, while rugged terrain and urban areas are also
    vulnerable.


    ...Central Plains into the Upper Midwest...
    A reasonably strong trough coming through the north-central U.S.
    will support a cold front slowly moving through the Midwest and
    Plains. Moisture and instability are forecast to pool along this
    cold front while the right entrance region of the jet provides
    ascent for rain/thunderstorms. The front should lay out a bit west-
    east by Tuesday evening/night and lead to a corridor of training
    convection. CAMs show axes of 3" totals with some minor spread in
    placement. Antecedent conditions are on the dry side in most areas,
    so this still looks like only a Marginal threat for flash flooding
    through Tuesday, but will continue to monitor trends for higher
    totals and agreement on the axis of heaviest totals for any
    potential Slight upgrade. Trimmed out the western area of the
    Marginal from the previous forecast due to less rain focusing there
    and falling over the Nebraska Sandhills.

    Tate


    Day 3
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    ...Central Plains to Mid/Upper Mississippi Valley...
    By Wednesday, the upper trough and front described in the Day 2
    discussion will further slow down and provide an axis for moisture
    to pool and thunderstorms to be persistent. Particularly given some
    potential overlap with rain the previous day affecting antecedent
    conditions, will continue to indicate a Slight Risk. There has been
    more model spread in the position of heaviest rain by Wednesday.
    While thunderstorms should be active all along the front through
    the Midwest back toward the central Plains, some guidance like the
    EC-AIFS and AIGFS are indicating the central Plains to Mid-
    Mississippi Valley should see the greatest rainfall totals.
    Expanded the Slight Risk to account for this southwestward
    potential, but maintained the Slight in the Chicago area too given
    some models (GFS/UKMET/NAM etc.) still show heavy rain over that
    area. Further shifts may happen in future cycles before models
    hopefully converge.


    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. This should keep
    supporting locally heavy rain in scattered thunderstorms, with high
    rain rates, so a Marginal Risk still looks good. Any areas seeing
    repeated rounds of rain from the previous couple of wet days would
    be particularly sensitive to flooding concerns. Convection may once
    again be enhanced over portions of the Florida Peninsula, but
    given a likely rainfall focus over the less sensitive areas of the
    Everglades westward, will not introduce a Marginal at this point.


    ...Southwest/Southern High Plains...
    On Wednesday, moist inflow on the southern part of the Southwest
    upper high will persist, though moisture transport anomalies seem
    to be a touch lower than the Monday/Tuesday values and with less of
    a focus for heavy rain placement. Therefore a Marginal Risk seems
    reasonable for isolated flooding and runoff issues for much of
    Arizona and New Mexico.

    Tate


    Day 4 and Day 5

    Valid 12Z Thu Aug 06 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...


    ...Central Plains into the Lower Missouri Valley...
    By Thursday...additional shortwave energy moving along the
    southern edge of the Westerlies into the Central High Plains may
    ignite another round of organized convection along the southward
    moving cold front from KS into MO. With low level southerly flow
    expected to strengthen Thursday night into early Friday morning
    into this front, locally heavy rains are possible. Given the
    moisture available, hourly rain amounts to 2.5" should be possible.
    The risk level near the front over the Central Plains toward the
    Lower MO Valley was kept at Marginal for Thursday night/early
    Friday morning.


    ...Lower Lakes, OH Valley into the Northern Mid Atlantic...
    A slow-moving frontal boundary expected to persist late this week.
    Shortwave energy expected to push east along the southern edge of
    the Westerlies, helping to accentuate lift in the high PW axis in
    the vicinity of this front. There is fairly good model qpf
    agreement on moderate to locally heavy precip totals across these
    areas, with hourly rain amounts up to 2.5" possible, supporting
    at least isolated runoff issues in urban areas and places with some
    degree of soil saturation.


    ...Southern to Central Appalachians...
    For late this week, a broad marginal risk is depicted through the
    Central to Southern Appalachians for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, hourly rain amounts to
    2.5" could lead to runoff issues, particularly in urban areas and
    within sharp relief.


    ...Southwest/Southern High Plains...
    For late this week, a Marginal Risk was depicted across much of
    the Southwest and Southern Rockies for monsoonal convection. The
    ridge placement across the southern Great Basin during the time
    frame along with some backing off in the moisture return on the
    guidance led to some reduction in the Marginal Risk area across
    southern NV. This led to less reliance on the 00z/12z ECMWF for the
    QPF breadth, which was collaborated with VEF/the Las Vegas NV
    forecast office. While there is continued low confidence with
    details, locally heavy rains with hourly amounts up to 2" could
    lead to isolated runoff issues.

    Roth/Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8VBhZ_9A_qwBxbJ9GRNktdBm2XWc23cKjeZbIN6bs6k0kf7iSv0do7J8MCc7uB0Dd2cSkehDIUgOjudOD2AvNgNSvHQ$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8VBhZ_9A_qwBxbJ9GRNktdBm2XWc23cKjeZbIN6bs6k0kf7iSv0do7J8MCc7uB0Dd2cSkehDIUgOjudOD2AvejM2G28$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8VBhZ_9A_qwBxbJ9GRNktdBm2XWc23cKjeZbIN6bs6k0kf7iSv0do7J8MCc7uB0Dd2cSkehDIUgOjudOD2AvfiSQ3CA$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 4 08:24:32 2026
    FOUS30 KWBC 040824
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    424 AM EDT Tue Aug 4 2026

    Day 1
    Valid 12Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    The Slight Risk still looks reasonable across south-
    southeast Arizona within a broader Marginal. Typical terrain
    features and burn scars will be particularly vulnerable to flash
    flooding concerns.

    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection Tuesday.
    The peak instability of 1000-2500 J/kg MUCAPE will be in southern
    Arizona. Above average moisture transport (4+ standardized
    anomalies for 850-700 mb moisture flux from the GFS, 2+ from the
    ECMWF) will be in place as well, allowing for heavy rain rates
    above 1"/hour. CAMs including the Arizona WRF indicate slow
    moving/westward moving convection potentially yielding increased
    amounts.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    A wandering upper low over the Southeast/southern Appalachians
    will be somewhat weak but still provide lower heights than normal
    for early August and broadly support ascent. Large areas of
    1000-2000 J/kg MUCAPE (locally higher) are expected in the
    southeastern U.S., while above average PWs are expected at least in
    eastern areas. Scattered convection is likely with high hourly
    rain rates, so a Marginal Risk remains in effect for portions of
    the Southeast, Appalachians, and southern Mid- Atlantic. Pockets of
    wet antecedent conditions could exacerbate flooding concerns,
    while rugged terrain and urban areas are also vulnerable.

    ...Central Plains into the Upper Midwest...

    A moderately strong trough advancing through the northern tier will
    send a leisurely cold front through the Midwest and Plains. Ahead
    of this system moisture and instability will pool across the
    region an when coupled with the right entrance region of the upper
    level jet there will be enhanced ascent for rain/thunderstorms
    development. The front's axis of orientation will generally be west
    to east which should be supportive of training convection. Hi-res
    guidance has a general consensus of 24 hour accumulations around 3
    inches; however given the recent drier period the threat for
    excessive rainfall and flash flooding impacts may be minimal thus
    maintained a Marginal Risk.

    Campbell/Tate


    Day 2
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    ...Central Plains to Mid/Upper Mississippi Valley...

    The upper trough and associated cold front described in the Day 2
    discussion will reduce to a snail's pace while providing an axis
    for moisture to pool and thunderstorms to focus. A Slight Risk for
    an elevated threat for excessive rainfall was maintained given
    some potential overlap with rain the previous day affecting
    antecedent conditions. There has been more model spread in the
    position of heaviest rain, but general consensus is along line from
    northeast Kansas to the Chicago vicinity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential. Convection
    may once again be enhanced over portions of the Florida Peninsula,
    but given a likely rainfall focus over the less sensitive areas of
    the Everglades westward, will not introduce a Marginal at this
    point.

    ...Southwest/Southern High Plains...
    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell/Tate


    Day 3
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    ...Central Plains into the Lower Missouri Valley...
    Another round of organized convection is expected to fire up along
    the southward moving cold front. During the overnight hours,
    moist, southerly flow will be increasing over the frontal boundary
    which will lead to locally heavy rainfall, potentially accumulation
    around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...
    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...
    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Not a lot of confidence in
    details, but with PW values expected to remain in the 1.5-1.75"+
    range, hourly rain amounts to 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...
    A Marginal Risk was maintained for much of the Southwest and
    Southern Rockies for monsoonal convection. The ridge placement
    across the southern Great Basin during the time frame along with
    some backing off in the moisture return on the guidance led to some
    reduction in the Marginal Risk area across southern Nevada. While
    there is continued low confidence with details, locally heavy rains
    with hourly amounts up to 2" could lead to isolated runoff issues.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Fri Aug 07 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE LOWER
    MISSISSIPPI VALLEY, NORTHEASTWARD INTO NEW ENGLAND, ACROSS THE
    UPPER MISSISSIPPI VALLEY AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...
    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower MS Valley, northeastward into New England
    in the southwest flow between the western Atlantic upper ridge and
    the broad mean trof across the Great Lakes into the OH Valley.
    Shortwave energy in this southwest flow will help accentuate lift
    in this high PW axis, supporting widespread scattered convection
    across these areas. There may be better organization to the
    convective activity across the Lower Lakes/OH Valley region in the
    vicinity of a slow moving frontal boundary expected to stretch west
    southwest to east northeast across this area. The risk level was
    maintained at marginal, but with FFG values relatively low across
    the eastern Lakes/Northern Mid-Atlantic, an upgrade is possible,
    especially as more hi res guidance becomes available.

    ...Southern to Central Appalachians...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians for the last week period for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in
    urban areas and within areas of steep terrain.

    ...Upper Mississippi Valley...
    Additional shortwave energy riding west to east along the southern
    edge of the westerlies will increase convective activity day 5 in
    the vicinity of a strengthening west to east oriented frontal
    boundary stretching from the Northern Plains into the Upper
    Mississippi Valley. The low level southerly to southwesterly flow
    is expected to strengthen into this front, increasing PW values to
    1.50-1.75"+ and supporting heavy to locally excessive rainfall
    totals in what may be an area of organized convection. The
    marginal risk area was drawn to encompass the current spread in
    model qpf axes.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8SC0-Z9LGV8-a0nL2y3pwNmBuFU9OY_vbiFvexmQVrabfflP1c7etf_RW7uuzTUnNu4_ro-1thxCm7WL0fQG6M0IfIM$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8SC0-Z9LGV8-a0nL2y3pwNmBuFU9OY_vbiFvexmQVrabfflP1c7etf_RW7uuzTUnNu4_ro-1thxCm7WL0fQGb-e4IaM$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8SC0-Z9LGV8-a0nL2y3pwNmBuFU9OY_vbiFvexmQVrabfflP1c7etf_RW7uuzTUnNu4_ro-1thxCm7WL0fQG3nUt2T0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 4 16:09:30 2026
    FOUS30 KWBC 041600
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1200 PM EDT Tue Aug 4 2026

    Day 1
    Valid 16Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    The Slight Risk still looks reasonable and was maintained with only
    minor adjustments across far southeast Arizona within a broader
    Marginal. Typical terrain features and burn scars will be
    particularly vulnerable to flash flooding concerns.

    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection this
    afternoon and tonight. The combination of 1500-3000 J/kg MUCAPE
    and above average moisture transport into the region (as shown by 4+ standardized anomalies greater than climatology for 850-700 mb
    moisture flux from the GFS and 2+ standardized anomalies from the
    ECMWF) should support rainfall rates above 1"/hour. Slow westward
    motion will contribute to enhanced rainfall amounts.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    Steep low- to mid-level lapse rates and a moisture rich atmosphere
    underneath a meandering upper low will support daytime and evening thunderstorms that pose an isolated risk of flash flooding in the
    region. The CAM guidance available this morning still depict a
    broad area of 1000-2000 J/kg MUCAPE (locally higher) with morning
    soundings showing 2 inch precipitable water values hugging the
    coastal areas and 1.75 to 2.0 inch amounts extending westward to
    near the Appalachians. Pockets of wet antecedent conditions could
    exacerbate flooding concerns, while rugged terrain and urban areas
    are also vulnerable.

    ...Central Plains into the Upper Midwest...

    A moderately strong trough advancing through the northern tier of
    states will send a cold front through the Upper Midwest today and
    into the Plains later tonight. Ahead of this system moisture and
    instability will pool across the region an when coupled with the
    right entrance region of the upper level jet there will be enhanced
    ascent for rain/thunderstorms development. The front's axis of
    orientation will generally be west to east which should be
    supportive of training convection. Hi-res guidance has a general
    consensus of 24 hour accumulations around 3 inches; however given
    the recent drier period the threat for excessive rainfall and flash
    flooding impacts may be minimal thus maintained a Marginal Risk.
    The only modification was to trim the Marginal risk area that was
    now in a more stable post-frontal environment.

    Bann/Campbell/Tate


    Day 2
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    ...Central Plains to Mid/Upper Mississippi Valley...

    The upper trough and associated cold front described in the Day 2
    discussion will reduce to a snail's pace while providing an axis
    for moisture to pool and thunderstorms to focus. A Slight Risk for
    an elevated threat for excessive rainfall was maintained given
    some potential overlap with rain the previous day affecting
    antecedent conditions. There has been more model spread in the
    position of heaviest rain, but general consensus is along line from
    northeast Kansas to the Chicago vicinity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential. Convection
    may once again be enhanced over portions of the Florida Peninsula,
    but given a likely rainfall focus over the less sensitive areas of
    the Everglades westward, will not introduce a Marginal at this
    point.

    ...Southwest/Southern High Plains...
    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell/Tate


    Day 3
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    ...Central Plains into the Lower Missouri Valley...
    Another round of organized convection is expected to fire up along
    the southward moving cold front. During the overnight hours,
    moist, southerly flow will be increasing over the frontal boundary
    which will lead to locally heavy rainfall, potentially accumulation
    around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...
    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...
    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Not a lot of confidence in
    details, but with PW values expected to remain in the 1.5-1.75"+
    range, hourly rain amounts to 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...
    A Marginal Risk was maintained for much of the Southwest and
    Southern Rockies for monsoonal convection. The ridge placement
    across the southern Great Basin during the time frame along with
    some backing off in the moisture return on the guidance led to some
    reduction in the Marginal Risk area across southern Nevada. While
    there is continued low confidence with details, locally heavy rains
    with hourly amounts up to 2" could lead to isolated runoff issues.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Fri Aug 07 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE LOWER
    MISSISSIPPI VALLEY, NORTHEASTWARD INTO NEW ENGLAND, ACROSS THE
    UPPER MISSISSIPPI VALLEY AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...
    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower MS Valley, northeastward into New England
    in the southwest flow between the western Atlantic upper ridge and
    the broad mean trof across the Great Lakes into the OH Valley.
    Shortwave energy in this southwest flow will help accentuate lift
    in this high PW axis, supporting widespread scattered convection
    across these areas. There may be better organization to the
    convective activity across the Lower Lakes/OH Valley region in the
    vicinity of a slow moving frontal boundary expected to stretch west
    southwest to east northeast across this area. The risk level was
    maintained at marginal, but with FFG values relatively low across
    the eastern Lakes/Northern Mid-Atlantic, an upgrade is possible,
    especially as more hi res guidance becomes available.

    ...Southern to Central Appalachians...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians for the last week period for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in
    urban areas and within areas of steep terrain.

    ...Upper Mississippi Valley...
    Additional shortwave energy riding west to east along the southern
    edge of the westerlies will increase convective activity day 5 in
    the vicinity of a strengthening west to east oriented frontal
    boundary stretching from the Northern Plains into the Upper
    Mississippi Valley. The low level southerly to southwesterly flow
    is expected to strengthen into this front, increasing PW values to
    1.50-1.75"+ and supporting heavy to locally excessive rainfall
    totals in what may be an area of organized convection. The
    marginal risk area was drawn to encompass the current spread in
    model qpf axes.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4tdRFC6r5eWOjGQoMDjuJcUkhAIrhTevzjdKQ9f1FRYapxAU3dwgB6FNyPZD7frYXRimmmCrmnrcxEF1bJy3-VlFCps$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4tdRFC6r5eWOjGQoMDjuJcUkhAIrhTevzjdKQ9f1FRYapxAU3dwgB6FNyPZD7frYXRimmmCrmnrcxEF1bJy3gXUy-O0$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4tdRFC6r5eWOjGQoMDjuJcUkhAIrhTevzjdKQ9f1FRYapxAU3dwgB6FNyPZD7frYXRimmmCrmnrcxEF1bJy3N2LJEZE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 4 19:30:18 2026
    FOUS30 KWBC 041929
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    329 PM EDT Tue Aug 4 2026

    Day 1
    Valid 16Z Tue Aug 04 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA...

    ...Southwest/Southern High Plains...
    The Slight Risk still looks reasonable and was maintained with only
    minor adjustments across far southeast Arizona within a broader
    Marginal. Typical terrain features and burn scars will be
    particularly vulnerable to flash flooding concerns.

    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection this
    afternoon and tonight. The combination of 1500-3000 J/kg MUCAPE
    and above average moisture transport into the region (as shown by 4+ standardized anomalies greater than climatology for 850-700 mb
    moisture flux from the GFS and 2+ standardized anomalies from the
    ECMWF) should support rainfall rates above 1"/hour. Slow westward
    motion will contribute to enhanced rainfall amounts.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    Steep low- to mid-level lapse rates and a moisture rich atmosphere
    underneath a meandering upper low will support daytime and evening thunderstorms that pose an isolated risk of flash flooding in the
    region. The CAM guidance available this morning still depict a
    broad area of 1000-2000 J/kg MUCAPE (locally higher) with morning
    soundings showing 2 inch precipitable water values hugging the
    coastal areas and 1.75 to 2.0 inch amounts extending westward to
    near the Appalachians. Pockets of wet antecedent conditions could
    exacerbate flooding concerns, while rugged terrain and urban areas
    are also vulnerable.

    ...Central Plains into the Upper Midwest...

    A moderately strong trough advancing through the northern tier of
    states will send a cold front through the Upper Midwest today and
    into the Plains later tonight. Ahead of this system moisture and
    instability will pool across the region an when coupled with the
    right entrance region of the upper level jet there will be enhanced
    ascent for rain/thunderstorms development. The front's axis of
    orientation will generally be west to east which should be
    supportive of training convection. Hi-res guidance has a general
    consensus of 24 hour accumulations around 3 inches; however given
    the recent drier period the threat for excessive rainfall and flash
    flooding impacts may be minimal thus maintained a Marginal Risk.
    The only modification was to trim the Marginal risk area that was
    now in a more stable post-frontal environment.

    Bann/Campbell/Tate


    Day 2
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    2030Z Update...
    Few changes needed. Numerical guidance continues to shift the focus
    for heavy rainfall and associated risk of flooding impacts
    southeastward during the period. Little reason to make changes
    given such consistency in the large-scale guidance.

    Bann

    Previous Discussion...

    ...Central Plains to Mid/Upper Mississippi Valley...

    The upper trough and associated cold front described in the Day 2
    discussion will reduce to a snail's pace while providing an axis
    for moisture to pool and thunderstorms to focus. A Slight Risk for
    an elevated threat for excessive rainfall was maintained given
    some potential overlap with rain the previous day affecting
    antecedent conditions. There has been more model spread in the
    position of heaviest rain, but general consensus is along line from
    northeast Kansas to the Chicago vicinity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential. Convection
    may once again be enhanced over portions of the Florida Peninsula,
    but given a likely rainfall focus over the less sensitive areas of
    the Everglades westward, will not introduce a Marginal at this
    point.

    ...Southwest/Southern High Plains...
    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell/Tate


    Day 3
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    2030Z Update...
    No changes needed to the Marginal risk area extending from the
    Southwest US through parts of the Central/Southern Plains eastward
    into parts of the Eastern US.

    Bann

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...
    Another round of organized convection is expected to fire up along
    the southward moving cold front. During the overnight hours,
    moist, southerly flow will be increasing over the frontal boundary
    which will lead to locally heavy rainfall, potentially accumulation
    around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...
    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...
    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Not a lot of confidence in
    details, but with PW values expected to remain in the 1.5-1.75"+
    range, hourly rain amounts to 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...
    A Marginal Risk was maintained for much of the Southwest and
    Southern Rockies for monsoonal convection. The ridge placement
    across the southern Great Basin during the time frame along with
    some backing off in the moisture return on the guidance led to some
    reduction in the Marginal Risk area across southern Nevada. While
    there is continued low confidence with details, locally heavy rains
    with hourly amounts up to 2" could lead to isolated runoff issues.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Fri Aug 07 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    2000 UTC Update: Fairly minor changes made to the Days 4 and 5
    EROs, based on the latest (12Z) operational and ensemble model
    guidance, both the deterministic and probabilistic QPFs. For the
    most part this resulted in a tightening of the Marginal Risk areas.

    Hurley

    Previous discussion...

    ...Lower Lakes, Ohio Valley into New England...
    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower MS Valley, northeastward into New England
    in the southwest flow between the western Atlantic upper ridge and
    the broad mean trof across the Great Lakes into the OH Valley.
    Shortwave energy in this southwest flow will help accentuate lift
    in this high PW axis, supporting widespread scattered convection
    across these areas. There may be better organization to the
    convective activity across the Lower Lakes/OH Valley region in the
    vicinity of a slow moving frontal boundary expected to stretch west
    southwest to east northeast across this area. The risk level was
    maintained at marginal, but with FFG values relatively low across
    the eastern Lakes/Northern Mid-Atlantic, an upgrade is possible,
    especially as more hi res guidance becomes available.

    ...Southern to Central Appalachians...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians for the last week period for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in
    urban areas and within areas of steep terrain.

    ...Upper Mississippi Valley...
    Additional shortwave energy riding west to east along the southern
    edge of the westerlies will increase convective activity day 5 in
    the vicinity of a strengthening west to east oriented frontal
    boundary stretching from the Northern Plains into the Upper
    Mississippi Valley. The low level southerly to southwesterly flow
    is expected to strengthen into this front, increasing PW values to
    1.50-1.75"+ and supporting heavy to locally excessive rainfall
    totals in what may be an area of organized convection. The
    marginal risk area was drawn to encompass the current spread in
    model qpf axes.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8-V_gaXoVoj-RwujQqCuv3GBG6CgJJVLiJ9r7O96ZR10B7TsF9GJfawiuI3he5z2xNHSqD76MZVTdfzAOBkDIos93Z8$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8-V_gaXoVoj-RwujQqCuv3GBG6CgJJVLiJ9r7O96ZR10B7TsF9GJfawiuI3he5z2xNHSqD76MZVTdfzAOBkDIIeM9fQ$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8-V_gaXoVoj-RwujQqCuv3GBG6CgJJVLiJ9r7O96ZR10B7TsF9GJfawiuI3he5z2xNHSqD76MZVTdfzAOBkD17WCFiY$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 4 21:55:24 2026
    FOUS30 KWBC 042155
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    555 PM EDT Tue Aug 4 2026

    Day 1
    Valid 2125Z Wed Aug 05 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA, THE MID ATLANTIC, AND MIDWEST...

    ...Southwest/Southern High Plains...

    The Slight Risk still looks reasonable and was maintained with only
    minor adjustments across far southeast Arizona within a broader
    Marginal. Typical terrain features and burn scars will be
    particularly vulnerable to flash flooding concerns.

    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection this
    afternoon and tonight. The combination of 1500-3000 J/kg MUCAPE
    and above average moisture transport into the region (as shown by 4+ standardized anomalies greater than climatology for 850-700 mb
    moisture flux from the GFS and 2+ standardized anomalies from the
    ECMWF) should support rainfall rates above 1"/hour. Slow westward
    motion will contribute to enhanced rainfall amounts.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    2130Z Update: Have included a Slight Risk across much of central-
    eastern VA, along with a small portion of north-central NC. Much of
    this is related to the ongoing activity -- organized, slow-moving
    convective clusters that lie within a ribbon of difluence aloft
    (downstream of the H5 closed low), with strong deep- layer
    moistening within an evolving Warm Conveyor Belt (WCB). TPW values
    are between 2.2-2.4" along and south of the surface warm/stationary
    boundary, quite sufficient for optimal warm rain processes as
    MLCAPEs average between 1000-1500 J/Kg. MRMS shows 3-6+ inches of
    rain within the last 3 hours from this activity. Expect the leading
    edge of the convection to diminish somewhat as it heads into a
    more stable environment across northern VA-southern MD later this
    evening (strong S-N TPW gradient); however, additional spokes of
    convection are expected to flare at least into the early evening
    hours across the Slight Risk area. The latest (18) HREF shows
    2"/hr rainfall rate probabilities dropping below 50% over the
    Slight Risk area by 2300Z.

    Hurley

    Previous discussion..

    Steep low-to mid-level lapse rates and a moisture rich atmosphere
    underneath a meandering upper low will support daytime and evening thunderstorms that pose an isolated risk of flash flooding in the
    region. The CAM guidance available this morning still depict a
    broad area of 1000-2000 J/kg MUCAPE (locally higher) with morning
    soundings showing 2 inch precipitable water values hugging the
    coastal areas and 1.75 to 2.0 inch amounts extending westward to
    near the Appalachians. Pockets of wet antecedent conditions could
    exacerbate flooding concerns, while rugged terrain and urban areas
    are also vulnerable.

    ...Central Plains into the Upper Midwest...

    2130Z Update: Have hoisted a Slight Risk across a small portion of
    southeastern NE along with southern IA, based on the latest
    observational trends along with short term CAM trends, including
    the 18Z HREF QPF exceedance probabilities. Current organized QLCS
    segments upstream are moving into an environment with 1.7-1.9" TPWs
    and 2000-3000 J/Kg of MUCAPE. Thermodynamically, the ingredients
    for heavy rainfall is most certainly there; the risk for excessive
    rainfall will ultimately come down to persistence/duration. Given
    the slow frontal progression, with hints already of some repetitive
    convection aligning more W-E, much of the latest mesoscale guidance
    (CAMs) are showing 3-5+ inches of additional rainfall after 00Z,
    with multiple rounds of elevated >1"/hr probabilities per the 18Z
    HREF, i.e. between 23-04Z, and again 04-12Z overnight.

    Hurley

    Previous discussion..

    A moderately strong trough advancing through the northern tier of
    states will send a cold front through the Upper Midwest today and
    into the Plains later tonight. Ahead of this system moisture and
    instability will pool across the region an when coupled with the
    right entrance region of the upper level jet there will be enhanced
    ascent for rain/thunderstorms development. The front's axis of
    orientation will generally be west to east which should be
    supportive of training convection. Hi-res guidance has a general
    consensus of 24 hour accumulations around 3 inches; however given
    the recent drier period the threat for excessive rainfall and flash
    flooding impacts may be minimal thus maintained a Marginal Risk.
    The only modification was to trim the Marginal risk area that was
    now in a more stable post-frontal environment.

    Bann/Campbell/Tate


    Day 2
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    2030Z Update...
    Few changes needed. Numerical guidance continues to shift the focus
    for heavy rainfall and associated risk of flooding impacts
    southeastward during the period. Little reason to make changes
    given such consistency in the large-scale guidance.

    Bann

    Previous Discussion...

    ...Central Plains to Mid/Upper Mississippi Valley...

    The upper trough and associated cold front described in the Day 2
    discussion will reduce to a snail's pace while providing an axis
    for moisture to pool and thunderstorms to focus. A Slight Risk for
    an elevated threat for excessive rainfall was maintained given
    some potential overlap with rain the previous day affecting
    antecedent conditions. There has been more model spread in the
    position of heaviest rain, but general consensus is along line from
    northeast Kansas to the Chicago vicinity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential. Convection
    may once again be enhanced over portions of the Florida Peninsula,
    but given a likely rainfall focus over the less sensitive areas of
    the Everglades westward, will not introduce a Marginal at this
    point.

    ...Southwest/Southern High Plains...
    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell/Tate


    Day 3
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    2030Z Update...
    No changes needed to the Marginal risk area extending from the
    Southwest US through parts of the Central/Southern Plains eastward
    into parts of the Eastern US.

    Bann

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...
    Another round of organized convection is expected to fire up along
    the southward moving cold front. During the overnight hours,
    moist, southerly flow will be increasing over the frontal boundary
    which will lead to locally heavy rainfall, potentially accumulation
    around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...
    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...
    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Not a lot of confidence in
    details, but with PW values expected to remain in the 1.5-1.75"+
    range, hourly rain amounts to 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...
    A Marginal Risk was maintained for much of the Southwest and
    Southern Rockies for monsoonal convection. The ridge placement
    across the southern Great Basin during the time frame along with
    some backing off in the moisture return on the guidance led to some
    reduction in the Marginal Risk area across southern Nevada. While
    there is continued low confidence with details, locally heavy rains
    with hourly amounts up to 2" could lead to isolated runoff issues.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Fri Aug 07 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    2000 UTC Update: Fairly minor changes made to the Days 4 and 5
    EROs, based on the latest (12Z) operational and ensemble model
    guidance, both the deterministic and probabilistic QPFs. For the
    most part this resulted in a tightening of the Marginal Risk areas.

    Hurley

    Previous discussion...

    ...Lower Lakes, Ohio Valley into New England...
    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower MS Valley, northeastward into New England
    in the southwest flow between the western Atlantic upper ridge and
    the broad mean trof across the Great Lakes into the OH Valley.
    Shortwave energy in this southwest flow will help accentuate lift
    in this high PW axis, supporting widespread scattered convection
    across these areas. There may be better organization to the
    convective activity across the Lower Lakes/OH Valley region in the
    vicinity of a slow moving frontal boundary expected to stretch west
    southwest to east northeast across this area. The risk level was
    maintained at marginal, but with FFG values relatively low across
    the eastern Lakes/Northern Mid-Atlantic, an upgrade is possible,
    especially as more hi res guidance becomes available.

    ...Southern to Central Appalachians...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians for the last week period for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in
    urban areas and within areas of steep terrain.

    ...Upper Mississippi Valley...
    Additional shortwave energy riding west to east along the southern
    edge of the westerlies will increase convective activity day 5 in
    the vicinity of a strengthening west to east oriented frontal
    boundary stretching from the Northern Plains into the Upper
    Mississippi Valley. The low level southerly to southwesterly flow
    is expected to strengthen into this front, increasing PW values to
    1.50-1.75"+ and supporting heavy to locally excessive rainfall
    totals in what may be an area of organized convection. The
    marginal risk area was drawn to encompass the current spread in
    model qpf axes.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6_Wa_504zq-FvJaLkxnfMmJkH-Cc4LNGFh7QpIP3R9PMt3ZcPdhwmuvduzr8WoLqO0v_SI7ke27xrvKaKN5Zf9wDJFg$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6_Wa_504zq-FvJaLkxnfMmJkH-Cc4LNGFh7QpIP3R9PMt3ZcPdhwmuvduzr8WoLqO0v_SI7ke27xrvKaKN5ZtYGpLLA$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6_Wa_504zq-FvJaLkxnfMmJkH-Cc4LNGFh7QpIP3R9PMt3ZcPdhwmuvduzr8WoLqO0v_SI7ke27xrvKaKN5ZvvH40a0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 00:32:56 2026
    FOUS30 KWBC 050032
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    832 PM EDT Tue Aug 4 2026

    Day 1
    Valid 2125Z Wed Aug 05 2026 - 12Z Wed Aug 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHERN ARIZONA, THE MID ATLANTIC, AND MIDWEST...

    ...Southwest/Southern High Plains...

    The Slight Risk still looks reasonable and was maintained with only
    minor adjustments across far southeast Arizona within a broader
    Marginal. Typical terrain features and burn scars will be
    particularly vulnerable to flash flooding concerns.

    Weak energy aloft could undercut the broad Southwest upper ridge
    to the south and provide support for enhanced convection this
    afternoon and tonight. The combination of 1500-3000 J/kg MUCAPE
    and above average moisture transport into the region (as shown by 4+ standardized anomalies greater than climatology for 850-700 mb
    moisture flux from the GFS and 2+ standardized anomalies from the
    ECMWF) should support rainfall rates above 1"/hour. Slow westward
    motion will contribute to enhanced rainfall amounts.

    ...Southeast to Southern/Central Appalachians into the Mid-
    Atlantic States...

    2130Z Update: Have included a Slight Risk across much of central-
    eastern VA, along with a small portion of north-central NC. Much of
    this is related to the ongoing activity -- organized, slow-moving
    convective clusters that lie within a ribbon of difluence aloft
    (downstream of the H5 closed low), with strong deep- layer
    moistening within an evolving Warm Conveyor Belt (WCB). TPW values
    are between 2.2-2.4" along and south of the surface warm/stationary
    boundary, quite sufficient for optimal warm rain processes as
    MLCAPEs average between 1000-1500 J/Kg. MRMS shows 3-6+ inches of
    rain within the last 3 hours from this activity. Expect the leading
    edge of the convection to diminish somewhat as it heads into a
    more stable environment across northern VA-southern MD later this
    evening (strong S-N TPW gradient); however, additional spokes of
    convection are expected to flare at least into the early evening
    hours across the Slight Risk area. The latest (18) HREF shows
    2"/hr rainfall rate probabilities dropping below 50% over the
    Slight Risk area by 2300Z.

    Hurley

    Previous discussion..

    Steep low-to mid-level lapse rates and a moisture rich atmosphere
    underneath a meandering upper low will support daytime and evening thunderstorms that pose an isolated risk of flash flooding in the
    region. The CAM guidance available this morning still depict a
    broad area of 1000-2000 J/kg MUCAPE (locally higher) with morning
    soundings showing 2 inch precipitable water values hugging the
    coastal areas and 1.75 to 2.0 inch amounts extending westward to
    near the Appalachians. Pockets of wet antecedent conditions could
    exacerbate flooding concerns, while rugged terrain and urban areas
    are also vulnerable.

    ...Central Plains into the Upper Midwest...

    2130Z Update: Have hoisted a Slight Risk across a small portion of
    southeastern NE along with southern IA, based on the latest
    observational trends along with short term CAM trends, including
    the 18Z HREF QPF exceedance probabilities. Current organized QLCS
    segments upstream are moving into an environment with 1.7-1.9" TPWs
    and 2000-3000 J/Kg of MUCAPE. Thermodynamically, the ingredients
    for heavy rainfall is most certainly there; the risk for excessive
    rainfall will ultimately come down to persistence/duration. Given
    the slow frontal progression, with hints already of some repetitive
    convection aligning more W-E, much of the latest mesoscale guidance
    (CAMs) are showing 3-5+ inches of additional rainfall after 00Z,
    with multiple rounds of elevated >1"/hr probabilities per the 18Z
    HREF, i.e. between 23-04Z, and again 04-12Z overnight.

    Hurley

    Previous discussion..

    A moderately strong trough advancing through the northern tier of
    states will send a cold front through the Upper Midwest today and
    into the Plains later tonight. Ahead of this system moisture and
    instability will pool across the region an when coupled with the
    right entrance region of the upper level jet there will be enhanced
    ascent for rain/thunderstorms development. The front's axis of
    orientation will generally be west to east which should be
    supportive of training convection. Hi-res guidance has a general
    consensus of 24 hour accumulations around 3 inches; however given
    the recent drier period the threat for excessive rainfall and flash
    flooding impacts may be minimal thus maintained a Marginal Risk.
    The only modification was to trim the Marginal risk area that was
    now in a more stable post-frontal environment.

    Bann/Campbell/Tate


    Day 2
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY...

    2030Z Update...
    Few changes needed. Numerical guidance continues to shift the focus
    for heavy rainfall and associated risk of flooding impacts
    southeastward during the period. Little reason to make changes
    given such consistency in the large-scale guidance.

    Bann

    Previous Discussion...

    ...Central Plains to Mid/Upper Mississippi Valley...

    The upper trough and associated cold front described in the Day 2
    discussion will reduce to a snail's pace while providing an axis
    for moisture to pool and thunderstorms to focus. A Slight Risk for
    an elevated threat for excessive rainfall was maintained given
    some potential overlap with rain the previous day affecting
    antecedent conditions. There has been more model spread in the
    position of heaviest rain, but general consensus is along line from
    northeast Kansas to the Chicago vicinity.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...
    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential. Convection
    may once again be enhanced over portions of the Florida Peninsula,
    but given a likely rainfall focus over the less sensitive areas of
    the Everglades westward, will not introduce a Marginal at this
    point.

    ...Southwest/Southern High Plains...
    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell/Tate


    Day 3
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, & EAST...

    2030Z Update...
    No changes needed to the Marginal risk area extending from the
    Southwest US through parts of the Central/Southern Plains eastward
    into parts of the Eastern US.

    Bann

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...
    Another round of organized convection is expected to fire up along
    the southward moving cold front. During the overnight hours,
    moist, southerly flow will be increasing over the frontal boundary
    which will lead to locally heavy rainfall, potentially accumulation
    around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...
    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...
    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Not a lot of confidence in
    details, but with PW values expected to remain in the 1.5-1.75"+
    range, hourly rain amounts to 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...
    A Marginal Risk was maintained for much of the Southwest and
    Southern Rockies for monsoonal convection. The ridge placement
    across the southern Great Basin during the time frame along with
    some backing off in the moisture return on the guidance led to some
    reduction in the Marginal Risk area across southern Nevada. While
    there is continued low confidence with details, locally heavy rains
    with hourly amounts up to 2" could lead to isolated runoff issues.

    Campbell/Roth


    Day 4 and Day 5

    Valid 12Z Fri Aug 07 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    2000 UTC Update: Fairly minor changes made to the Days 4 and 5
    EROs, based on the latest (12Z) operational and ensemble model
    guidance, both the deterministic and probabilistic QPFs. For the
    most part this resulted in a tightening of the Marginal Risk areas.

    Hurley

    Previous discussion...

    ...Lower Lakes, Ohio Valley into New England...
    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower MS Valley, northeastward into New England
    in the southwest flow between the western Atlantic upper ridge and
    the broad mean trof across the Great Lakes into the OH Valley.
    Shortwave energy in this southwest flow will help accentuate lift
    in this high PW axis, supporting widespread scattered convection
    across these areas. There may be better organization to the
    convective activity across the Lower Lakes/OH Valley region in the
    vicinity of a slow moving frontal boundary expected to stretch west
    southwest to east northeast across this area. The risk level was
    maintained at marginal, but with FFG values relatively low across
    the eastern Lakes/Northern Mid-Atlantic, an upgrade is possible,
    especially as more hi res guidance becomes available.

    ...Southern to Central Appalachians...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians for the last week period for widespread scattered
    convection. Not a lot of confidence in details, but with PW values
    expected to remain in the 1.5-1.75"+ range, localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in
    urban areas and within areas of steep terrain.

    ...Upper Mississippi Valley...
    Additional shortwave energy riding west to east along the southern
    edge of the westerlies will increase convective activity day 5 in
    the vicinity of a strengthening west to east oriented frontal
    boundary stretching from the Northern Plains into the Upper
    Mississippi Valley. The low level southerly to southwesterly flow
    is expected to strengthen into this front, increasing PW values to
    1.50-1.75"+ and supporting heavy to locally excessive rainfall
    totals in what may be an area of organized convection. The
    marginal risk area was drawn to encompass the current spread in
    model qpf axes.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!433yMGreLDzte2EwG1_zxSFzuScoWBxe61B_gUAWGH60UCYqAPCS9qh1VHFGVS1tUrORJyZUlAcW_uzOCr6RxdfsaKA$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!433yMGreLDzte2EwG1_zxSFzuScoWBxe61B_gUAWGH60UCYqAPCS9qh1VHFGVS1tUrORJyZUlAcW_uzOCr6RzEXPzQo$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!433yMGreLDzte2EwG1_zxSFzuScoWBxe61B_gUAWGH60UCYqAPCS9qh1VHFGVS1tUrORJyZUlAcW_uzOCr6RftBtXj0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 08:06:54 2026
    FOUS30 KWBC 050806
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    406 AM EDT Wed Aug 5 2026

    Day 1
    Valid 12Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ALONG THE SOUTH
    CAROLINA COAST...

    ...Central Plains to Mid/Upper Mississippi Valley...

    An upper level trough and associated cold front will continue its
    sluggish trek through the central/north-central states.
    Thunderstorms are expected to fire along/ahead of the frontal
    boundary and will be steadily fueled by an influx of Gulf moisture
    northward into the boundary. The latest guidance depicted a modest
    southward trend with the location of the highest QPF thus the
    entire Slight Risk was adjusted accordingly for an elevated threat
    for excessive rainfall was maintained given some potential overlap
    with rain the previous day affecting antecedent conditions.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential.
    Convection overnight along the South Carolina coast may bleed into
    the initial hours of this forecast period. Charleston and the urban
    corridor are very sensitive to rainfall intensities of 1-2
    inches/hour, which may materialize early this morning. Therefore a
    targeted Slight Risk area was raised for much of the South Carolina
    Coastline and back into the Charleston metro.

    Convection may once again be enhanced over portions of the Florida
    Peninsula, but given a likely rainfall focus over the less
    sensitive areas of the Everglades westward. There is a non zero
    potential for excessive rainfall and/or very isolated flash
    flooding concerns.

    ...Southwest/Southern High Plains...

    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!60jnRQFXMnJAvV12C8_q94hatEzZw3q7MfBf61pc33hI32ktjyi75_zDaIK9WdFnzLaCWVyteVxM8WopjPZFDAASzGY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!60jnRQFXMnJAvV12C8_q94hatEzZw3q7MfBf61pc33hI32ktjyi75_zDaIK9WdFnzLaCWVyteVxM8WopjPZFPpOn6DM$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!60jnRQFXMnJAvV12C8_q94hatEzZw3q7MfBf61pc33hI32ktjyi75_zDaIK9WdFnzLaCWVyteVxM8WopjPZF0r8Ma0Q$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 16:00:24 2026
    FOUS30 KWBC 051556
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1156 AM EDT Wed Aug 5 2026

    Day 1
    Valid 16Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ALONG THE SOUTH
    CAROLINA COAST...

    1630Z Update...
    Previous outlook was in good shape and only minor
    westward/northwestward expansion of the Slight Risk area was needed
    to account for another wave of showers and thunderstorms
    approaching from the west. HREF and RREFS guidance still offered a
    difference of opinion with the HREF favoring additional moderate to
    heavy rainfall in parts of southeast Iowa and western Missouri
    while the RREFS was more focused in Iowa. The Slight Risk area
    covered both possibilities. Heavy rainfall also lingered near the
    coast of South Carolina where 2000+ J per kg of ML CAPE
    lingered...so felt it was too soon to remove the outlook area. No
    other changes were needed.

    Bann

    Previous Excessive Rainfall Discussion...

    ...Central Plains to Mid/Upper Mississippi Valley...

    An upper level trough and associated cold front will continue its
    sluggish trek through the central/north-central states.
    Thunderstorms are expected to fire along/ahead of the frontal
    boundary and will be steadily fueled by an influx of Gulf moisture
    northward into the boundary. The latest guidance depicted a modest
    southward trend with the location of the highest QPF thus the
    entire Slight Risk was adjusted accordingly for an elevated threat
    for excessive rainfall was maintained given some potential overlap
    with rain the previous day affecting antecedent conditions.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential.
    Convection overnight along the South Carolina coast may bleed into
    the initial hours of this forecast period. Charleston and the urban
    corridor are very sensitive to rainfall intensities of 1-2
    inches/hour, which may materialize early this morning. Therefore a
    targeted Slight Risk area was raised for much of the South Carolina
    Coastline and back into the Charleston metro.

    Convection may once again be enhanced over portions of the Florida
    Peninsula, but given a likely rainfall focus over the less
    sensitive areas of the Everglades westward. There is a non zero
    potential for excessive rainfall and/or very isolated flash
    flooding concerns.

    ...Southwest/Southern High Plains...

    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6PYO9DcUyEJyF4CPPVrv3IctMp5O8Z-V-tG5a1pxt0N5Ys1h9wKQ2ZumnaumTK0xVOi08Sz7IqtkkRqHKLxa6vbtOxE$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6PYO9DcUyEJyF4CPPVrv3IctMp5O8Z-V-tG5a1pxt0N5Ys1h9wKQ2ZumnaumTK0xVOi08Sz7IqtkkRqHKLxaYl4lYPY$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6PYO9DcUyEJyF4CPPVrv3IctMp5O8Z-V-tG5a1pxt0N5Ys1h9wKQ2ZumnaumTK0xVOi08Sz7IqtkkRqHKLxaUr1Qtbw$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 19:59:10 2026
    FOUS30 KWBC 051958
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    358 PM EDT Wed Aug 5 2026

    Day 1
    Valid 16Z Wed Aug 05 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ALONG THE SOUTH
    CAROLINA COAST...

    1630Z Update...
    Previous outlook was in good shape and only minor
    westward/northwestward expansion of the Slight Risk area was needed
    to account for another wave of showers and thunderstorms
    approaching from the west. HREF and RREFS guidance still offered a
    difference of opinion with the HREF favoring additional moderate to
    heavy rainfall in parts of southeast Iowa and western Missouri
    while the RREFS was more focused in Iowa. The Slight Risk area
    covered both possibilities. Heavy rainfall also lingered near the
    coast of South Carolina where 2000+ J per kg of ML CAPE
    lingered...so felt it was too soon to remove the outlook area. No
    other changes were needed.

    Bann

    Previous Excessive Rainfall Discussion...

    ...Central Plains to Mid/Upper Mississippi Valley...

    An upper level trough and associated cold front will continue its
    sluggish trek through the central/north-central states.
    Thunderstorms are expected to fire along/ahead of the frontal
    boundary and will be steadily fueled by an influx of Gulf moisture
    northward into the boundary. The latest guidance depicted a modest
    southward trend with the location of the highest QPF thus the
    entire Slight Risk was adjusted accordingly for an elevated threat
    for excessive rainfall was maintained given some potential overlap
    with rain the previous day affecting antecedent conditions.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential.
    Convection overnight along the South Carolina coast may bleed into
    the initial hours of this forecast period. Charleston and the urban
    corridor are very sensitive to rainfall intensities of 1-2
    inches/hour, which may materialize early this morning. Therefore a
    targeted Slight Risk area was raised for much of the South Carolina
    Coastline and back into the Charleston metro.

    Convection may once again be enhanced over portions of the Florida
    Peninsula, but given a likely rainfall focus over the less
    sensitive areas of the Everglades westward. There is a non zero
    potential for excessive rainfall and/or very isolated flash
    flooding concerns.

    ...Southwest/Southern High Plains...

    There will be a persistent influx of moisture along the southern
    periphery of the Southwest upper high, although its been noted that
    there is a less focused area for where higher QPF will occur. A
    Marginal Risk remains for much of Arizona and New Mexico for
    isolated flooding and runoff issues.

    Campbell


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    21Z Update..

    The previous outlook remains in good shape, and virtually no
    change was made to the inherited risk areas. Latest HREF
    neighborhood probabilities over the southern Appalachians
    indicated medium chances of 24hr rainfall exceeding 3", and low
    chances of precip exceeding FFGs which may bring isolated flash
    flooding. However, CAM guidance suggests a rather short period of
    heavy precip, and there was a general lack of agreement regarding
    the location precip core, and QPF totals.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    21Z update...

    Virtually no change was made with this update, other than cosmetic
    changes with the updated suite of global and ensemble guidance.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    2000Z Update: Only minor (cosmetic) changes were made based on the
    latest deterministic and probabilistic guidance, including the 12Z
    AIGFS and the ECMWF AIFS.

    Hurley

    Previous discussion below..

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4jlCulCMc-yw0Xm4wRg0FCKHYTptLMhqxLtTr0JRdTXS6gU12Ll7PDBDmmW5TcgJu33-yeaxsqs9mRLmhWR1318rIfY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4jlCulCMc-yw0Xm4wRg0FCKHYTptLMhqxLtTr0JRdTXS6gU12Ll7PDBDmmW5TcgJu33-yeaxsqs9mRLmhWR1fndIacI$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4jlCulCMc-yw0Xm4wRg0FCKHYTptLMhqxLtTr0JRdTXS6gU12Ll7PDBDmmW5TcgJu33-yeaxsqs9mRLmhWR1M3ZHRgg$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 21:38:34 2026
    FOUS30 KWBC 052138
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    538 PM EDT Wed Aug 5 2026

    Day 1
    Valid 2100Z Thu Aug 06 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ACROSS SOUTHERN
    ARIZONA...

    ...Central Plains to Mid/Upper Mississippi Valley...

    2100Z Update: Based on what has already occurred today, along with
    the latest observational and guidance (CAM) trends for this evening
    and overnight, have pared a bit of the Slight Risk area, removing
    portions across IA and north-central to northeast IL. Elevated
    2"/hr rainfall rate probabilities per the 18Z HREF begin to
    percolate across eastern KS-western MO after 05Z, then spread into
    central and northern MO thereafter.

    Hurley

    Previous discussion below..

    An upper level trough and associated cold front will
    continue its sluggish trek through the central/north-central
    states. Thunderstorms are expected to fire along/ahead of the
    frontal boundary and will be steadily fueled by an influx of Gulf
    moisture northward into the boundary. The latest guidance depicted
    a modest southward trend with the location of the highest QPF thus
    the entire Slight Risk was adjusted accordingly for an elevated
    threat for excessive rainfall was maintained given some potential
    overlap with rain the previous day affecting antecedent conditions.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential.
    Convection overnight along the South Carolina coast may bleed into
    the initial hours of this forecast period. Charleston and the urban
    corridor are very sensitive to rainfall intensities of 1-2
    inches/hour, which may materialize early this morning. Therefore a
    targeted Slight Risk area was raised for much of the South Carolina
    Coastline and back into the Charleston metro.

    Convection may once again be enhanced over portions of the Florida
    Peninsula, but given a likely rainfall focus over the less
    sensitive areas of the Everglades westward. There is a non zero
    potential for excessive rainfall and/or very isolated flash
    flooding concerns.

    ...Southwest/Southern High Plains...

    2100Z Update: Per collaboration with WFO Tucson, we have included
    a Slight Risk across south-central and southeast AZ in this special
    Day 1 ERO update. This corresponds to Tucson's flood watch, which
    is in effect until 05Z this evening. Pattern has not changed much
    overall compared to the past few days (previous Slight Risk days),
    with the moisture anomaly present and mesoscale enhanced/induced
    shortwave energy moving westerly underneath the flat mid/upper
    ridge. While not ideal thermodynamically (mixed layer CAPEs peaking
    around 1000-1500 J/Kg, PWs ~1.25 to 1.5"), when combined with the
    forcing between 2300-0500Z, the mesoscale guidance (all CAMs) show
    concentrated areas of heavy rainfall within this Slight Risk area,
    with areal average amounts of 1-2.5" and localized totals of 3-5"
    (NAM CONUS Nest and RRFS being the heaviest. Latest HREF and REFS
    QPF exceedance probabilities have also come up as a result during
    the late afternoon and evening hours.

    Elsewhere surrounding the Slight, the Marginal Risk area remains
    sufficient, as areas of heavy (potentially excessive) rainfall will
    be isolated at best.

    Hurley


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    21Z Update..

    The previous outlook remains in good shape, and virtually no
    change was made to the inherited risk areas. Latest HREF
    neighborhood probabilities over the southern Appalachians
    indicated medium chances of 24hr rainfall exceeding 3", and low
    chances of precip exceeding FFGs which may bring isolated flash
    flooding. However, CAM guidance suggests a rather short period of
    heavy precip, and there was a general lack of agreement regarding
    the location precip core, and QPF totals.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    21Z update...

    Virtually no change was made with this update, other than cosmetic
    changes with the updated suite of global and ensemble guidance.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    2000Z Update: Only minor (cosmetic) changes were made based on the
    latest deterministic and probabilistic guidance, including the 12Z
    AIGFS and the ECMWF AIFS.

    Hurley

    Previous discussion below..

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4nVFUHnBh8fPxGAwIl0IK3sJktOatJdFhgsbCfKtvFynL3TuCN-jt-PT7SP5KaOUgND-pDiqmT3OOgOhNSXAZBpito4$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4nVFUHnBh8fPxGAwIl0IK3sJktOatJdFhgsbCfKtvFynL3TuCN-jt-PT7SP5KaOUgND-pDiqmT3OOgOhNSXAqDH4jw4$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4nVFUHnBh8fPxGAwIl0IK3sJktOatJdFhgsbCfKtvFynL3TuCN-jt-PT7SP5KaOUgND-pDiqmT3OOgOhNSXA3vNQZnI$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Wed Aug 5 21:55:58 2026
    FOUS30 KWBC 052155
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    555 PM EDT Wed Aug 5 2026

    Day 1
    Valid 2100Z Thu Aug 06 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ACROSS SOUTHERN
    ARIZONA...

    ...Central Plains to Mid/Upper Mississippi Valley...

    2100Z Update: Based on what has already occurred today, along with
    the latest observational and guidance (CAM) trends for this evening
    and overnight, have pared a bit of the Slight Risk area, removing
    portions across IA and north-central to northeast IL. Elevated
    2"/hr rainfall rate probabilities per the 18Z HREF begin to
    percolate across eastern KS-western MO after 05Z, then spread into
    central and northern MO thereafter.

    Hurley

    Previous discussion below..

    An upper level trough and associated cold front will
    continue its sluggish trek through the central/north-central
    states. Thunderstorms are expected to fire along/ahead of the
    frontal boundary and will be steadily fueled by an influx of Gulf
    moisture northward into the boundary. The latest guidance depicted
    a modest southward trend with the location of the highest QPF thus
    the entire Slight Risk was adjusted accordingly for an elevated
    threat for excessive rainfall was maintained given some potential
    overlap with rain the previous day affecting antecedent conditions.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    Whatever is left of the upper level trough across the eastern U.S.
    should devolve into a shear line by midweek. However, a moist and
    unstable environment (PWs greater than the 75th percentile in an
    already moist season of the year) will continue and expand
    northwestward as the upper energy shifts. Scattered rainfall with
    high rain rates can be expected thus maintaining a Marginal Risk
    for excessive rainfall and local flash flooding potential.
    Convection overnight along the South Carolina coast may bleed into
    the initial hours of this forecast period. Charleston and the urban
    corridor are very sensitive to rainfall intensities of 1-2
    inches/hour, which may materialize early this morning. Therefore a
    targeted Slight Risk area was raised for much of the South Carolina
    Coastline and back into the Charleston metro.

    Convection may once again be enhanced over portions of the Florida
    Peninsula, but given a likely rainfall focus over the less
    sensitive areas of the Everglades westward. There is a non zero
    potential for excessive rainfall and/or very isolated flash
    flooding concerns.

    ...Southwest/Southern High Plains...

    2100Z Update: Per collaboration with WFO Tucson, we have included
    a Slight Risk across south-central and southeast AZ in this special
    Day 1 ERO update. This corresponds to Tucson's flood watch, which
    is in effect until 06Z this evening. Pattern has not changed much
    overall compared to the past few days (previous Slight Risk days),
    with the moisture anomaly present and mesoscale enhanced/induced
    shortwave energy moving westerly underneath the flat mid/upper
    ridge. While not ideal thermodynamically (mixed layer CAPEs peaking
    around 1000-1500 J/Kg, PWs ~1.25 to 1.5"), when combined with the
    forcing between 2300-0600Z, the mesoscale guidance (all CAMs) show
    concentrated areas of heavy rainfall within this Slight Risk area,
    with areal average amounts of 1-2.5" and localized totals of 3-5"
    (NAM CONUS Nest and RRFS being the heaviest. Latest HREF and REFS
    QPF exceedance probabilities have also come up as a result during
    the late afternoon and evening hours.

    Elsewhere surrounding the Slight, the Marginal Risk area remains
    sufficient, as areas of heavy (potentially excessive) rainfall will
    be isolated at best.

    Hurley


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    21Z Update..

    The previous outlook remains in good shape, and virtually no
    change was made to the inherited risk areas. Latest HREF
    neighborhood probabilities over the southern Appalachians
    indicated medium chances of 24hr rainfall exceeding 3", and low
    chances of precip exceeding FFGs which may bring isolated flash
    flooding. However, CAM guidance suggests a rather short period of
    heavy precip, and there was a general lack of agreement regarding
    the location precip core, and QPF totals.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    21Z update...

    Virtually no change was made with this update, other than cosmetic
    changes with the updated suite of global and ensemble guidance.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    2000Z Update: Only minor (cosmetic) changes were made based on the
    latest deterministic and probabilistic guidance, including the 12Z
    AIGFS and the ECMWF AIFS.

    Hurley

    Previous discussion below..

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8sXC0_WxLFsmQ4F96VDf44woQqojENM2xsA7zybsjFEC57Sy8O93fS2jJDsOWzsGhchG0AxH2ix4PXayG07btdVsWy4$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8sXC0_WxLFsmQ4F96VDf44woQqojENM2xsA7zybsjFEC57Sy8O93fS2jJDsOWzsGhchG0AxH2ix4PXayG07bTmUy_Pg$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8sXC0_WxLFsmQ4F96VDf44woQqojENM2xsA7zybsjFEC57Sy8O93fS2jJDsOWzsGhchG0AxH2ix4PXayG07bDCBYH34$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Aug 6 00:38:16 2026
    FOUS30 KWBC 060037
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    837 PM EDT Wed Aug 5 2026

    Day 1
    Valid 01Z Thu Aug 06 2026 - 12Z Thu Aug 06 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE CENTRAL PLAINS TO MIDDLE MISSISSIPPI VALLEY AND ACROSS SOUTHERN
    ARIZONA...

    ...Central Plains to Mid/Upper Mississippi Valley...

    2100Z Update: Based on what has already occurred today, along with
    the latest observational and guidance (CAM) trends for this evening
    and overnight, have pared a bit of the Slight Risk area, removing
    portions across IA and north-central to northeast IL. Elevated
    2"/hr rainfall rate probabilities per the 18Z HREF begin to
    percolate across eastern KS-western MO after 05Z, then spread into
    central and northern MO thereafter.

    ...Southern to Central Appalachians into the Northern Mid-
    Atlantic...

    0100Z Update: Continued to trim the Marginal Risk area, leaving in
    areas only where observational trends (radar, satellite,
    mesoanalysis) still support a short term risk for flash flooding
    (through ~0600Z). Most extensive convective coverage early this
    evening is across the higher terrain (western slopes of the
    Appalachians in particular), where some spotty FFWs are still being
    issued. Given the weak mid level lapse rates (~6 C/KM between
    700-500 mb) and thus decreasing deep-layer CAPE trends following
    sunset, expect the already minimal flash flood risk to diminish
    towards midnight EDT or shortly thereafter.

    ...Southwest/Southern High Plains...

    2100Z Update: Per collaboration with WFO Tucson, we have included
    a Slight Risk across south-central and southeast AZ in this special
    Day 1 ERO update. This corresponds to Tucson's flood watch, which
    is in effect until 06Z this evening. Pattern has not changed much
    overall compared to the past few days (previous Slight Risk days),
    with the moisture anomaly present and mesoscale enhanced/induced
    shortwave energy moving westerly underneath the flat mid/upper
    ridge. While not ideal thermodynamically (mixed layer CAPEs peaking
    around 1000-1500 J/Kg, PWs ~1.25 to 1.5"), when combined with the
    forcing between 2300-0600Z, the mesoscale guidance (all CAMs) show
    concentrated areas of heavy rainfall within this Slight Risk area,
    with areal average amounts of 1-2.5" and localized totals of 3-5"
    (NAM CONUS Nest and RRFS being the heaviest. Latest HREF and REFS
    QPF exceedance probabilities have also come up as a result during
    the late afternoon and evening hours.

    Elsewhere surrounding the Slight, the Marginal Risk area remains
    sufficient, as areas of heavy (potentially excessive) rainfall will
    be isolated at best.

    Hurley


    Day 2
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    21Z Update..

    The previous outlook remains in good shape, and virtually no
    change was made to the inherited risk areas. Latest HREF
    neighborhood probabilities over the southern Appalachians
    indicated medium chances of 24hr rainfall exceeding 3", and low
    chances of precip exceeding FFGs which may bring isolated flash
    flooding. However, CAM guidance suggests a rather short period of
    heavy precip, and there was a general lack of agreement regarding
    the location precip core, and QPF totals.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. During the overnight hours, moist, southerly
    flow will be increasing over the frontal boundary which will lead
    to locally heavy rainfall, potentially accumulation around 2.5
    inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. Lasted guidance continues to
    have a fair amount of spread in QPF amounts and placement of the
    highest accumulations. Although the details remain uncertain, PW
    values are expected to remain in the 1.5-1.75"+ range so hourly
    rain amounts upwards of 2.5" could lead to runoff issues,
    particularly in urban areas and within sharp relief.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 3
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    21Z update...

    Virtually no change was made with this update, other than cosmetic
    changes with the updated suite of global and ensemble guidance.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    An axis of high PW values...1.50-1.75"+ expected to continue to
    stretch from the Lower Mississippi Valley, northeastward into New
    England in the southwest flow between the western Atlantic upper
    ridge and the broad mean trof across the Great Lakes into the Ohio
    Valley. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area. The risk level was maintained at marginal, but with FFG
    values relatively low across the eastern Lakes/Northern Mid-
    Atlantic, an upgrade is possible, especially as more hi res
    guidance becomes available.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will persist across the
    region during this period aiding in the local enhancement of the
    widespread scattered convection. A broad Marginal Risk covers the
    Central to Southern Appalachians where localized hourly rain
    amounts of 1-2"+ could lead to runoff issues, particularly in urban
    areas and within areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell/Oravec


    Day 4 and Day 5

    Valid 12Z Sat Aug 08 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE NORTHERN PLAINS ACROSS THE LOWER
    LAKES AND INTO THE NORTHEAST AND ACROSS THE CENTRAL TO SOUTHERN
    APPALACHIANS...

    2000Z Update: Only minor (cosmetic) changes were made based on the
    latest deterministic and probabilistic guidance, including the 12Z
    AIGFS and the ECMWF AIFS.

    Hurley

    Previous discussion below..

    For both the day 4 and 5 period, broad cyclonic flow expected to
    persist across the northern tier of the CONUS from the Northern
    Plains/Upper MS Valley, eastward through the Lower Lakes and into
    the Northeast. A frontal boundary is the mean will persist along
    the southern edge of the westerlies on the south side of this broad
    trof. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front this weekend where PW
    values are expected to rise to 1.50-1.75" ahead of each set of
    shortwave energy.

    ...Lower Lakes/Upper OH Valley into northern New England...
    For day 4...a lead area of height falls moving along the southern
    edge of the westerlies will support widespread scattered convection
    from the Lower Lakes/Upper OH Valley, east northeastward into much
    of NY State and northern New England. Locally heavy rains and
    isolated runoff issues possible.

    ...Upper MS Valley into the Mid-West...
    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...
    A broad marginal risk is depicted through the Central to Southern
    Appalachians into the Southeast day 4 and across the Central to
    Southern Appalachians day 5 for widespread scattered convection.
    Not a lot of confidence in details, but with PW values expected to
    remain in the 1.5-1.75"+ range, localized hourly rain amounts of
    1-2"+ could lead to runoff issues, particularly in urban areas and
    within areas of steep terrain.

    ...Northern Plains/Upper MS Valley into the Lower Lakes...
    No changes to the large scale pattern for day 5, as shortwave
    energy continues to push east southeastward along the southern edge
    of the westerlies. The combination of the lead area of shortwave
    energy that moved into the Upper MS Valley/Mid West region day 4
    moving downstream into the Lower Lakes and additional upstream
    shortwave energy moving from the Northern Plains into the Upper MS
    Valley day 5, will support a widespread region of potentially
    locally heavy rains and isolated runoff issues. Confidence is low
    with qpf details, but there will be the potential for organized
    convection in the vicinity of the west to east oriented front,
    supporting locally heavy rains and isolated runoff issues.

    ..Southwest...
    No significant changes to the broad marginal risk area across the
    Southwest for monsoonal convection both day 4 and day 5. While
    there continues to be low confidence with qpf details, locally
    heavy rains and isolated runoff issues will continue in the axis of
    above average PW values expected across this area.

    Oravec


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6U2CmeIfw7eL_pGKCAkv8M2wvX5QSC-3tK3NvZkmDqEmzxbOVaknPplmoabBOh1MfdLu8nPM5z5dpye0qy_zkRnc9MU$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6U2CmeIfw7eL_pGKCAkv8M2wvX5QSC-3tK3NvZkmDqEmzxbOVaknPplmoabBOh1MfdLu8nPM5z5dpye0qy_zuMHs0XA$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6U2CmeIfw7eL_pGKCAkv8M2wvX5QSC-3tK3NvZkmDqEmzxbOVaknPplmoabBOh1MfdLu8nPM5z5dpye0qy_z6SPHIPs$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Aug 6 07:57:24 2026
    FOUS30 KWBC 060757
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    357 AM EDT Thu Aug 6 2026

    Day 1
    Valid 12Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. An increasing influx of moist, southerly flow
    over the frontal boundary overnight will lead to locally heavy
    rainfall, potentially accumulating around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. HREF neighborhood probabilities over the southern
    Appalachians indicated medium chances of 24hr rainfall exceeding
    3", and low chances of precip exceeding FFGs which may bring
    isolated flash flooding. CAM guidance suggests a rather short
    period of heavy precip, and there was a general lack of agreement
    regarding the location precip core, and QPF totals.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 2
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...

    During this period a PW plume of 1.50-1.75 inches will be pooled
    across much of the central states to New England within the
    southwest flow sandwiched between the upper ridge over the Atlantic
    and a broad mean trough over the Great Lakes and Ohio Valley
    region. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will hold steady across
    the region aiding in the local enhancement of the widespread
    scattered convection. A broad Marginal Risk covers the Central to
    Southern Appalachians where localized hourly rain amounts of 1-2"+
    could lead to runoff issues, particularly in urban areas and within
    areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell


    Day 3
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE PLAINS/MISSISSIPPI VALLEY
    AND ACROSS THE LOWER LAKES AND INTO THE NORTHEAST AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    ...Lower Lakes/Upper OH Valley into northern New England...

    A frontal boundary will persist along the southern edge of the
    westerlies on the south side of a broad trof. Embedded shortwaves
    in this broad cyclonic flow will accentuate lift in the vicinity of
    this front where PW values are expected to rise to 1.50-1.75"
    ahead of each set of shortwave energy. Height falls moving along
    the southern edge of the westerlies will support widespread
    scattered convection from the Lower Lakes/Upper Ohio Valley, east
    northeastward into much of New York state and northern New England.
    Locally heavy rains and isolated runoff issues will be possible,
    thus maintaining a Marginal Risk area.

    ...Upper Mississippi Valley into the Mid-West...

    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...

    A broad Marginal Risk remains in effect for widespread convection.
    Although confidence in the location of higher amounts remains lower,
    PW values in the 1.5-1.75"+ range will support localized hourly
    rain amounts of 1-2"+ leading to potential runoff issues,
    particularly in urban areas and within areas of steep terrain.

    ..Southwest...

    A broad Marginal Risk area was maintained across the Southwest for
    monsoonal convection. Low confidence with QPF details persist
    however locally heavy rains and isolated runoff issues will
    continue in the axis of above average PW values across this area.

    Campbell


    Day 4 and Day 5

    Valid 12Z Sun Aug 09 2026 - 12Z Tue Aug 11 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, NORTHERN PLAINS, GREAT LAKES, MIDWEST, & NORTHERN MID-ATLANTIC STATES...

    ...Northern Plains/Great Lakes/Midwest/Northern Mid-Atlantic
    states...
    Early next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    early next week where PW values are expected to rise to ~1.75"
    ahead of each set of shortwaves. When looking at the ingredients,
    organized convection looks most likely south of the Great Lakes
    within portions of the Corn Belt, where hourly rain amounts to 2.5"
    are possible. However, there is a great deal of latitudinal spread
    in the axis due to differences between where the diffluent
    1000-500 hPa thickness exists and where the instability
    gradient/better 850 hPa confluence/convergence could set up, which
    appears more poleward into the Great Lakes. When the guidance gets
    in better agreement at some future time, a Slight Risk or greater
    could be considered, but at the moment there's too much spread in
    the heavy rain signal to place anything more than a Marginal Risk.

    ..Southwest...
    Broad Marginal Risk areas exist both days across portions of the
    Southwest, Rockies, and Great Basin. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2" an hour amounts and isolated runoff issues will
    continue in the axis of above average PW values expected across
    this area. As usual, urban areas, arroyos/dry washes, box canyons,
    and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7DK-4RCr1UXItqG3EQfSNAs5qtYH-CneVYt6WRlAMkM32M19B8oneCfjKKNyRqHjkXgqbfhJaUZtnWCMxuwLygIcCWY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7DK-4RCr1UXItqG3EQfSNAs5qtYH-CneVYt6WRlAMkM32M19B8oneCfjKKNyRqHjkXgqbfhJaUZtnWCMxuwLM2RIQTA$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7DK-4RCr1UXItqG3EQfSNAs5qtYH-CneVYt6WRlAMkM32M19B8oneCfjKKNyRqHjkXgqbfhJaUZtnWCMxuwLOAxMRsc$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Aug 6 15:45:00 2026
    FOUS30 KWBC 061544
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1144 AM EDT Thu Aug 6 2026

    Day 1
    Valid 16Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    16Z Update..

    Only minor changes were needed for this update. The MRGL Risk area
    was trimmed to remove parts of northern MO, given radar trends. The
    majority of rainfall associated with an overnight MCS has moved
    through northern and central MO at this time. A very minor
    expansion in the Northeast was also needed to include the entire
    state of VT as an influx of anomalously high PWATs (over 2 standard
    deviations above normal) fuels short-lived heavy rainfall. Latest
    runs of both HREF and RRFS neighborhood probabilities indicate
    medium-to-high chances (~50-60%) of 1hr rates exceeding 1". Given
    how extremely localized the heaviest rainfall will be, along with
    the short duration of rainfall, an upgrade was not considered, but
    isolated flash flooding here will remain a concern.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. An increasing influx of moist, southerly flow
    over the frontal boundary overnight will lead to locally heavy
    rainfall, potentially accumulating around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. HREF neighborhood probabilities over the southern
    Appalachians indicated medium chances of 24hr rainfall exceeding
    3", and low chances of precip exceeding FFGs which may bring
    isolated flash flooding. CAM guidance suggests a rather short
    period of heavy precip, and there was a general lack of agreement
    regarding the location precip core, and QPF totals.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 2
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    ...Lower Lakes, Ohio Valley into New England...

    During this period a PW plume of 1.50-1.75 inches will be pooled
    across much of the central states to New England within the
    southwest flow sandwiched between the upper ridge over the Atlantic
    and a broad mean trough over the Great Lakes and Ohio Valley
    region. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will hold steady across
    the region aiding in the local enhancement of the widespread
    scattered convection. A broad Marginal Risk covers the Central to
    Southern Appalachians where localized hourly rain amounts of 1-2"+
    could lead to runoff issues, particularly in urban areas and within
    areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell


    Day 3
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE PLAINS/MISSISSIPPI VALLEY
    AND ACROSS THE LOWER LAKES AND INTO THE NORTHEAST AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    ...Lower Lakes/Upper OH Valley into northern New England...

    A frontal boundary will persist along the southern edge of the
    westerlies on the south side of a broad trof. Embedded shortwaves
    in this broad cyclonic flow will accentuate lift in the vicinity of
    this front where PW values are expected to rise to 1.50-1.75"
    ahead of each set of shortwave energy. Height falls moving along
    the southern edge of the westerlies will support widespread
    scattered convection from the Lower Lakes/Upper Ohio Valley, east
    northeastward into much of New York state and northern New England.
    Locally heavy rains and isolated runoff issues will be possible,
    thus maintaining a Marginal Risk area.

    ...Upper Mississippi Valley into the Mid-West...

    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...

    A broad Marginal Risk remains in effect for widespread convection.
    Although confidence in the location of higher amounts remains lower,
    PW values in the 1.5-1.75"+ range will support localized hourly
    rain amounts of 1-2"+ leading to potential runoff issues,
    particularly in urban areas and within areas of steep terrain.

    ..Southwest...

    A broad Marginal Risk area was maintained across the Southwest for
    monsoonal convection. Low confidence with QPF details persist
    however locally heavy rains and isolated runoff issues will
    continue in the axis of above average PW values across this area.

    Campbell


    Day 4 and Day 5

    Valid 12Z Sun Aug 09 2026 - 12Z Tue Aug 11 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, NORTHERN PLAINS, GREAT LAKES, MIDWEST, & NORTHERN MID-ATLANTIC STATES...

    ...Northern Plains/Great Lakes/Midwest/Northern Mid-Atlantic
    states...
    Early next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    early next week where PW values are expected to rise to ~1.75"
    ahead of each set of shortwaves. When looking at the ingredients,
    organized convection looks most likely south of the Great Lakes
    within portions of the Corn Belt, where hourly rain amounts to 2.5"
    are possible. However, there is a great deal of latitudinal spread
    in the axis due to differences between where the diffluent
    1000-500 hPa thickness exists and where the instability
    gradient/better 850 hPa confluence/convergence could set up, which
    appears more poleward into the Great Lakes. When the guidance gets
    in better agreement at some future time, a Slight Risk or greater
    could be considered, but at the moment there's too much spread in
    the heavy rain signal to place anything more than a Marginal Risk.

    ..Southwest...
    Broad Marginal Risk areas exist both days across portions of the
    Southwest, Rockies, and Great Basin. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2" an hour amounts and isolated runoff issues will
    continue in the axis of above average PW values expected across
    this area. As usual, urban areas, arroyos/dry washes, box canyons,
    and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!-r7lZaw-Y6zNdmJPInxIdJQk8FUY0D5RiAb6zGER8uYlLtxDRFrlav1s2RJWLuLemkQl0s5Vdfzy71B6DVKUTk82qas$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!-r7lZaw-Y6zNdmJPInxIdJQk8FUY0D5RiAb6zGER8uYlLtxDRFrlav1s2RJWLuLemkQl0s5Vdfzy71B6DVKUBvc55O4$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!-r7lZaw-Y6zNdmJPInxIdJQk8FUY0D5RiAb6zGER8uYlLtxDRFrlav1s2RJWLuLemkQl0s5Vdfzy71B6DVKU1rsm8nM$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Thu Aug 6 19:38:02 2026
    FOUS30 KWBC 061937
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    337 PM EDT Thu Aug 6 2026

    Day 1
    Valid 16Z Thu Aug 06 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND
    EAST...

    16Z Update..

    Only minor changes were needed for this update. The MRGL Risk area
    was trimmed to remove parts of northern MO, given radar trends. The
    majority of rainfall associated with an overnight MCS has moved
    through northern and central MO at this time. A very minor
    expansion in the Northeast was also needed to include the entire
    state of VT as an influx of anomalously high PWATs (over 2 standard
    deviations above normal) fuels short-lived heavy rainfall. Latest
    runs of both HREF and RRFS neighborhood probabilities indicate
    medium-to-high chances (~65%) of 1hr rates exceeding 1". Given how
    extremely localized the heaviest rainfall will be, along with the
    short duration of rainfall, an upgrade was not considered, but
    isolated flash flooding here will remain a concern.

    Blanco-Alcala

    Previous Discussion...

    ...Central Plains into the Lower Missouri Valley...

    Organized convection is expected to fire up along the southward
    moving cold front. An increasing influx of moist, southerly flow
    over the frontal boundary overnight will lead to locally heavy
    rainfall, potentially accumulating around 2.5 inches.

    ...Lower Lakes, Ohio Valley into the Northern Mid-Atlantic...

    A slow-moving frontal boundary expected to persist as shortwave
    energy track east along the southern edge of the Westerlies,
    helping to accentuate lift in the high PW axis in the vicinity of
    this front. Moderate to locally heavy rain totals expected with
    hourly rain amounts up to 2.5" possible, supporting at least
    isolated runoff issues in urban areas and places with some degree
    of soil saturation.

    ...Southern to Central Appalachians...

    A broad Marginal Risk covers the Central to Southern Appalachians
    for widespread scattered convection. HREF neighborhood probabilities over the southern
    Appalachians indicated medium chances of 24hr rainfall exceeding
    3", and low chances of precip exceeding FFGs which may bring
    isolated flash flooding. CAM guidance suggests a rather short
    period of heavy precip, and there was a general lack of agreement
    regarding the location precip core, and QPF totals.

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Campbell


    Day 2
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    1930Z Update..

    Very minor changes were needed for the risk areas. The main change
    of note was a minor reduction to the MRGL area in central AR.
    Latest run of CAMs guidance suggest a progressive line of
    thunderstorms in the northern and central portions of AR, where
    rainfall will be heavy but relatively short-lived. FFGs are also
    high (~3"), and the progressive nature of the system should limit
    flash flooding potential.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    During this period a PW plume of 1.50-1.75 inches will be pooled
    across much of the central states to New England within the
    southwest flow sandwiched between the upper ridge over the Atlantic
    and a broad mean trough over the Great Lakes and Ohio Valley
    region. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will hold steady across
    the region aiding in the local enhancement of the widespread
    scattered convection. A broad Marginal Risk covers the Central to
    Southern Appalachians where localized hourly rain amounts of 1-2"+
    could lead to runoff issues, particularly in urban areas and within
    areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell


    Day 3
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE PLAINS/MISSISSIPPI VALLEY
    AND ACROSS THE LOWER LAKES AND INTO THE NORTHEAST AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    1930Z Update..

    A minor reduction of the MRGL Risk area was needed for Iowa and
    northern Illinois as the QPF core becomes better defined. A
    progressive convective system is forecast to move through Iowa
    along the periphery of an upper ridge. PWAT anomalies, particularly
    in the ECMWF, are quite high at around 3 standard deviations above
    normal. SREF Spaghetti plots are also in agreement in a heavy
    precipitation core located in central to southern Iowa. As such, a
    targeted Slight upgrade may be possible in the area in future
    updates, but due to global model disagreement in terms on the
    location of the heaviest precipitation, a MRGL was maintained until
    CAMs guidance becomes available.

    Blanco-Alcala

    ...Lower Lakes/Upper OH Valley into northern New England...

    A frontal boundary will persist along the southern edge of the
    westerlies on the south side of a broad trof. Embedded shortwaves
    in this broad cyclonic flow will accentuate lift in the vicinity of
    this front where PW values are expected to rise to 1.50-1.75"
    ahead of each set of shortwave energy. Height falls moving along
    the southern edge of the westerlies will support widespread
    scattered convection from the Lower Lakes/Upper Ohio Valley, east
    northeastward into much of New York state and northern New England.
    Locally heavy rains and isolated runoff issues will be possible,
    thus maintaining a Marginal Risk area.

    ...Upper Mississippi Valley into the Mid-West...

    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...

    A broad Marginal Risk remains in effect for widespread convection.
    Although confidence in the location of higher amounts remains lower,
    PW values in the 1.5-1.75"+ range will support localized hourly
    rain amounts of 1-2"+ leading to potential runoff issues,
    particularly in urban areas and within areas of steep terrain.

    ..Southwest...

    A broad Marginal Risk area was maintained across the Southwest for
    monsoonal convection. Low confidence with QPF details persist
    however locally heavy rains and isolated runoff issues will
    continue in the axis of above average PW values across this area.

    Campbell


    Day 4 and Day 5

    Valid 12Z Sun Aug 09 2026 - 12Z Tue Aug 11 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, NORTHERN PLAINS, GREAT LAKES, MIDWEST, &
    NORTHERN MID-ATLANTIC STATES...

    1930Z Update: The only notable change to both the Days 4-5 EROs was
    to cut back a little across the western portions of the Marginal
    Risk areas over the Northern Plains, specifically the Dakotas. This
    based on the 12Z guidance trends, including the 12Z AIGFS and ECMWF
    AIFS, along with the QPF exceedance probabilities from the 12Z
    GEFS and ECENS means.

    Hurley

    ...Northern Plains/Great Lakes/Midwest/Northern Mid-Atlantic
    states...
    Early next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    early next week where PW values are expected to rise to ~1.75"
    ahead of each set of shortwaves. When looking at the ingredients,
    organized convection looks most likely south of the Great Lakes
    within portions of the Corn Belt, where hourly rain amounts to 2.5"
    are possible. However, there is a great deal of latitudinal spread
    in the axis due to differences between where the diffluent
    1000-500 hPa thickness exists and where the instability
    gradient/better 850 hPa confluence/convergence could set up, which
    appears more poleward into the Great Lakes. When the guidance gets
    in better agreement at some future time, a Slight Risk or greater
    could be considered, but at the moment there's too much spread in
    the heavy rain signal to place anything more than a Marginal Risk.

    ..Southwest...
    Broad Marginal Risk areas exist both days across portions of the
    Southwest, Rockies, and Great Basin. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2" an hour amounts and isolated runoff issues will
    continue in the axis of above average PW values expected across
    this area. As usual, urban areas, arroyos/dry washes, box canyons,
    and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!9KNnLaMPpUWi_9qtuS2lQW17876YZdJoaHFl9xXnUD3DMB41ILUh15dRZN8iVMyLzKJ51NUUi9OnpR7BouCCkkVICBk$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!9KNnLaMPpUWi_9qtuS2lQW17876YZdJoaHFl9xXnUD3DMB41ILUh15dRZN8iVMyLzKJ51NUUi9OnpR7BouCCUEcmDiI$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!9KNnLaMPpUWi_9qtuS2lQW17876YZdJoaHFl9xXnUD3DMB41ILUh15dRZN8iVMyLzKJ51NUUi9OnpR7BouCCdlclR70$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Aug 7 00:25:24 2026
    FOUS30 KWBC 070025
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    825 PM EDT Thu Aug 6 2026

    Day 1
    Valid 01Z Fri Aug 07 2026 - 12Z Fri Aug 07 2026

    ...THERE IS A BROAD MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
    SOUTHWEST THROUGH THE CENTRAL/SOUTHERN PLAINS, MIDWEST, AND EAST...

    ...Central Plains into the Lower Missouri Valley and Midwest..

    0100Z Update: Any additional organized convection overnight along
    and south of the quasi-stationary front is expected across
    southeastern KS into northeast OK given the latest CAM trends,
    including the 18Z HREF QPF exceedance probabilities. This given the
    nocturnal uptick in the 925-850 mb flow (increase in 0-6km Bulk
    shear), healthy deep-layer instability (MUCAPEs 2000-3000+ J/Kg),
    and PWs approaching 1.75". However, given the degree of low-mid
    level shear along/near this quasi-stationary surface front
    (especially directional), strong northerly MBE or Corfidi Vectors
    will allow for a fairly swift southerly motion of any organized
    convective segments exhibiting upscale growth, thus limiting the
    risk for cell training overnight. The latest HRRR simulated
    reflectivity guidance supports this.

    ...Eastern U.S....

    0100Z Update: A slow-moving frontal boundary expected to persist
    as shortwave energy track east along the southern edge of the
    Westerlies, helping to accentuate lift in the high PW axis in the
    vicinity of this front. Moderate to locally heavy rain totals
    expected with hourly rain amounts up to 2.5" possible, supporting
    at least isolated runoff issues in urban areas and places with some
    degree of soil saturation. The loss of peak heating however will
    substantially reduce the risk (i.e. to "sub Marginal") after
    03-05Z, given the weak 0-6km bulk shear and weak mid-level lapse
    rates (~6 C/Km).

    ...Southwest/Southern High Plains...

    Monsoonal convection will continue through this period thus the
    Marginal Risk was maintained for much of the Southwest and Southern
    Rockies. While there is continued low confidence with details,
    locally heavy rains with hourly amounts up to 2" could lead to
    isolated runoff issues.

    Hurley


    Day 2
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
    THE LOWER AND MID MISSISSIPPI VALLEY EAST AND NORTHEAST INTO THE
    MID ATLANTIC AND NEW ENGLAND, ACROSS THE UPPER MISSISSIPPI VALLEY,
    AND OVER THE SOUTHWEST...

    21Z Update..

    Very minor changes were needed for the risk areas. The main change
    of note was a minor reduction to the MRGL area in central AR.
    Latest run of CAMs guidance suggest a progressive line of
    thunderstorms in the northern and central portions of AR, where
    rainfall will be heavy but relatively short-lived. FFGs are also
    high (~3"), and the progressive nature of the system should limit
    flash flooding potential.

    Blanco-Alcala

    Previous Discussion...

    ...Lower Lakes, Ohio Valley into New England...

    During this period a PW plume of 1.50-1.75 inches will be pooled
    across much of the central states to New England within the
    southwest flow sandwiched between the upper ridge over the Atlantic
    and a broad mean trough over the Great Lakes and Ohio Valley
    region. Shortwave energy in this southwest flow will help
    accentuate lift in this high PW axis, supporting widespread
    scattered convection across these areas. There may be better
    organization to the convective activity across the Lower Lakes/Ohio
    Valley region in the vicinity of a slow moving frontal boundary
    expected to stretch west southwest to east northeast across this
    area.

    ...Southern to Central Appalachians...

    PW values in the 1.5 to 1.75 inches range will hold steady across
    the region aiding in the local enhancement of the widespread
    scattered convection. A broad Marginal Risk covers the Central to
    Southern Appalachians where localized hourly rain amounts of 1-2"+
    could lead to runoff issues, particularly in urban areas and within
    areas of steep terrain.

    ..Southwest...

    While there continues to be low confidence with QPF details,
    locally heavy rains and isolated runoff issues will continue in the
    axis of above average PW values expected across this area. A
    Marginal Risk area remains in effect for much of Arizona and New
    Mexico.

    Campbell


    Day 3
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, FROM PORTIONS OF THE PLAINS/MISSISSIPPI VALLEY
    AND ACROSS THE LOWER LAKES AND INTO THE NORTHEAST AND ACROSS THE
    CENTRAL TO SOUTHERN APPALACHIANS...

    21Z Update..

    A minor reduction of the MRGL Risk area was needed for Iowa and
    northern Illinois as the QPF core becomes better defined. A
    progressive convective system is forecast to move through Iowa
    along the periphery of an upper ridge. PWAT anomalies, particularly
    in the ECMWF, are quite high at around 3 standard deviations above
    normal. SREF Spaghetti plots are also in agreement in a heavy
    precipitation core located in central to southern Iowa. As such, a
    targeted Slight upgrade may be possible in the area in future
    updates, but due to global model disagreement in terms on the
    location of the heaviest precipitation, a MRGL was maintained until
    CAMs guidance becomes available.

    Blanco-Alcala

    ...Lower Lakes/Upper OH Valley into northern New England...

    A frontal boundary will persist along the southern edge of the
    westerlies on the south side of a broad trof. Embedded shortwaves
    in this broad cyclonic flow will accentuate lift in the vicinity of
    this front where PW values are expected to rise to 1.50-1.75"
    ahead of each set of shortwave energy. Height falls moving along
    the southern edge of the westerlies will support widespread
    scattered convection from the Lower Lakes/Upper Ohio Valley, east
    northeastward into much of New York state and northern New England.
    Locally heavy rains and isolated runoff issues will be possible,
    thus maintaining a Marginal Risk area.

    ...Upper Mississippi Valley into the Mid-West...

    This will be followed by a second area shortwave energy pushing
    east southeast from the Northern Plains into the Upper MS
    Valley/Mid West region Saturday night into early Sunday. The low
    level southerly to southwesterly flow is expected to strengthen
    into this front, increasing PW values to 1.50-1.75"+ and supporting
    heavy to locally excessive rainfall totals in what may be an area
    of organized convection. The marginal risk area was drawn to
    encompass the current spread in model qpf axes.

    ...Southern to Central Appalachians into the Southeast...

    A broad Marginal Risk remains in effect for widespread convection.
    Although confidence in the location of higher amounts remains lower,
    PW values in the 1.5-1.75"+ range will support localized hourly
    rain amounts of 1-2"+ leading to potential runoff issues,
    particularly in urban areas and within areas of steep terrain.

    ..Southwest...

    A broad Marginal Risk area was maintained across the Southwest for
    monsoonal convection. Low confidence with QPF details persist
    however locally heavy rains and isolated runoff issues will
    continue in the axis of above average PW values across this area.

    Campbell


    Day 4 and Day 5

    Valid 12Z Sun Aug 09 2026 - 12Z Tue Aug 11 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHWEST, NORTHERN PLAINS, GREAT LAKES, MIDWEST, &
    NORTHERN MID-ATLANTIC STATES...

    1930Z Update: The only notable change to both the Days 4-5 EROs was
    to cut back a little across the western portions of the Marginal
    Risk areas over the Northern Plains, specifically the Dakotas. This
    based on the 12Z guidance trends, including the 12Z AIGFS and ECMWF
    AIFS, along with the QPF exceedance probabilities from the 12Z
    GEFS and ECENS means.

    Hurley

    ...Northern Plains/Great Lakes/Midwest/Northern Mid-Atlantic
    states...
    Early next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    early next week where PW values are expected to rise to ~1.75"
    ahead of each set of shortwaves. When looking at the ingredients,
    organized convection looks most likely south of the Great Lakes
    within portions of the Corn Belt, where hourly rain amounts to 2.5"
    are possible. However, there is a great deal of latitudinal spread
    in the axis due to differences between where the diffluent
    1000-500 hPa thickness exists and where the instability
    gradient/better 850 hPa confluence/convergence could set up, which
    appears more poleward into the Great Lakes. When the guidance gets
    in better agreement at some future time, a Slight Risk or greater
    could be considered, but at the moment there's too much spread in
    the heavy rain signal to place anything more than a Marginal Risk.

    ..Southwest...
    Broad Marginal Risk areas exist both days across portions of the
    Southwest, Rockies, and Great Basin. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2" an hour amounts and isolated runoff issues will
    continue in the axis of above average PW values expected across
    this area. As usual, urban areas, arroyos/dry washes, box canyons,
    and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8rOLvs7d0Vwjl4br3GueJhPu7-se_F7tGnjja45OQcVBN7NOxYxlIkQ2zvorm6_haXEK-_jR3vT8CCOLNJ4AqI9QjYo$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8rOLvs7d0Vwjl4br3GueJhPu7-se_F7tGnjja45OQcVBN7NOxYxlIkQ2zvorm6_haXEK-_jR3vT8CCOLNJ4AF5v9g4c$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8rOLvs7d0Vwjl4br3GueJhPu7-se_F7tGnjja45OQcVBN7NOxYxlIkQ2zvorm6_haXEK-_jR3vT8CCOLNJ4AnZ6PMcI$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Aug 7 07:37:48 2026
    FOUS30 KWBC 070737
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    337 AM EDT Fri Aug 7 2026

    Day 1
    Valid 12Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR THE SOUTHWEST
    THROUGH MUCH OF THE EAST, MIDWEST, AND SOUTH...

    Marginal Risks for excessive rainfall cover large portions of the
    country from the Southwest through much of the eastern half of the
    country. The Marginal was expanded to include much of Oklahoma and
    north Texas, as well as expanded through Louisiana and portions of
    the central Gulf Coast, as well as much of Florida.

    Abundant deep tropical moisture is in place across much of the
    Southeast and up the Eastern Seaboard. Forcings remain mesoscale,
    as the synoptic pattern with a trough generally along the northern
    tier of states generally is not overlapping most of the deepest
    moisture. Thus, where there is enough forcing, there's a lack of
    moisture, and in large swaths of the country where there's plenty
    of moisture, a lack of a defining synoptic feature to provide
    forcing will likely mean any storms will be reliant on smaller
    mesoscale features such as local terrain, cold pools, sea breezes
    etc. to get them going.

    Due to a lack of defining features overall, large Marginals remain
    the most prudent forecast. However, given the aforementioned deep
    tropical moisture over much of the country, it's quite feasible
    that there will be Slight Risk levels of impacts wherever the
    storms can interact with each other in a positive way. This appears
    most likely on Friday across portions of Arkansas, where the deep
    tropical moisture will run into the terrain of the Ozarks, and the
    base of the distant upper level trough could provide a bit of
    organization to the convection. That said, the very dry soils from
    the lack of rainfall across the state in recent days will make
    Slight level impacts difficult to attain.

    From eastern Ohio through much of Pennsylvania and southern New
    York, there too will have some minimal amount of forcing from weak
    upper level shortwaves running over the abundant summertime
    moisture in place across much of the east. Here too there is a
    higher risk of Slight Risk level impacts, in part due to low FFGs.
    Convection across this region looks to be quite progressive though,
    so it will likely take topographic enhancement in localized areas
    to produce enough rain to produce widely scattered instances of
    flash flooding. These should be few and far between enough to not
    need a Slight there for now.

    Wegman


    Day 2
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR THE
    SOUTHWEST, PORTIONS OF THE MIDWEST, AND MUCH OF THE EASTERN
    SEABOARD...

    Monsoonal moisture across the Southwest will continue on Saturday,
    especially across Arizona. As usual, the greatest rainfall will be
    along the Mexican border where the Gulf of California's influence
    is greatest, as well as along the Mogollon Rim. There appears to be
    little rain in between in the populated areas. Lack of signal for
    more organized heavy rain should preclude a Slight Risk upgrade.

    Across the Midwest, specifically Iowa, an overnight Saturday night
    MCS is expected to impact much of Iowa and small portions of the
    neighboring states. While guidance has come into better agreement
    on the areas likely to be affected, there remains a broad variety
    of solutions as to how much rain will fall across much of central
    and eastern Iowa. Thus, for now the area remains in a Marginal, but
    will continue to be monitored for a Slight risk upgrade with future
    updates.

    Signals for heavy rain across much of the Eastern Seaboard remain
    very diffuse again on Saturday. Similar to Friday, there remains
    plentiful moisture all up and down the Atlantic coast. Somewhat
    better forcing from a negatively tilted trough north of the Great
    Lakes should allow for more widespread storms, but they will remain
    quite progressive. Further south, there will be more moisture, but
    a lack of forcing. Most of the heaviest rains look to be from north
    Florida through coastal South Carolina.

    Wegman


    Day 3
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER MIDWEST AND UPPER MISSISSIPPI VALLEY...

    ...Upper Midwest...
    Multiple rounds of storms are expected on Sunday across portions
    of the upper Midwest, specifically from the southeast corner of
    Minnesota southeast through northern Indiana. With plentiful
    moisture from an LLJ originating from the Gulf being advected
    northward into the storms, there is little reason to see why the
    storms won't be able to backbuild and train both with the morning
    convection with an MCS, and then secondarily with late afternoon
    through the Sunday night convection across these same areas. Since
    guidance has come into better agreement, even better than Days 1
    and 2, a Slight Risk upgrade was introduced with this update.


    ...Elsewhere...
    Elsewhere, the Southwest monsoon will continue to promote
    afternoon and evening convective development into the 4 Corners
    region, and southwesterly moisture advection into the southern
    Appalachians could also provide a focus (due to terrain) for
    afternoon and evening storms. As on prior days, widespread widely
    scattered convection is likely all across the Southeast Sunday
    afternoon and evening. Should storms merge over urban areas, then
    flash flooding is quite possible outside of the drawn Marginal Risk
    area. Thus, it's probable additional expansions and changes will
    be needed over the coming days into the Southeast.

    Wegman


    Day 4 and Day 5

    Valid 12Z Mon Aug 10 2026 - 12Z Wed Aug 12 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN AND NEAR
    NORTHERN INDIANA...

    ...Great Lakes/Midwest...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~1.75" ahead of each set
    of shortwaves and low-level confluence is expected. When looking
    at the ingredients, organized convection looks most likely south of
    the Great Lakes within eastern portions of the Corn Belt, where
    hourly rain amounts to 2.5" are possible. Due to a bit better
    agreement in the guidance, and the southward trends towards where
    conceptual models would have placed a Slight Risk 24 hours ago,
    went ahead and added a Slight Risk for areas in and around northern
    IN both days. While there is still some possibility of further
    southward trends, this trend may materialize more as a later
    southward expansion as we get closer to the event.

    ..Southwest...
    Broad Marginal Risk areas exist both days early to mid next week across portions of the Southwest, Rockies, and Great Basin. While there
    continues to be low confidence with the details, locally heavy
    rains with the potential of 2" an hour amounts and isolated runoff
    issues will continue in the axis of above average PW values
    expected across this area. As usual, urban areas, arroyos/dry
    washes, box canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_wulsQ7PiGX-EhhDKsxUIZaVGfA3E6t7gve5k5RDzDAchSUKFpcEaDQEykt5ov0LseKPKHmuLVi1m7yxLfLAmW6OL5c$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_wulsQ7PiGX-EhhDKsxUIZaVGfA3E6t7gve5k5RDzDAchSUKFpcEaDQEykt5ov0LseKPKHmuLVi1m7yxLfLAZpDVwOs$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_wulsQ7PiGX-EhhDKsxUIZaVGfA3E6t7gve5k5RDzDAchSUKFpcEaDQEykt5ov0LseKPKHmuLVi1m7yxLfLAvTvxpeo$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Fri Aug 7 15:47:50 2026
    FOUS30 KWBC 071547
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1147 AM EDT Fri Aug 7 2026

    Day 1
    Valid 16Z Fri Aug 07 2026 - 12Z Sat Aug 08 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PARTS OF THE
    NORTHEAST AND THE NORTHERN MID-ATLANTIC...

    16Z Update..

    A Slight Risk was introduced in this update for eastern
    Pennsylvania, southeast New York, and northern New Jersey. A pulse
    of upper-level forcing by way of a shortwave will quickly move
    through the northern Mid-Atlantic in the afternoon hours.
    Anomalously high moisture availability, with PWATs exceeding 2", is
    also expected. A line of short- lived thunderstorms will bring
    heavy rainfall, in the afternoon and early evening, with hourly
    rain rates potentially reaching and/or exceeding 2"/hr. Previous rainfall
    over the past few days have also lowered FFGs, to where areas in
    eastern PA, southern NY, and northern NJ only need around 0.5-0.75"
    per hour to exceed them. Latest HREF and RRFS runs also support
    the potential, with medium-to-high chances (~65%) in the FFGs
    exceedance probabilities in both models. As such, and in
    coordination with the OKX, LWK, PHI, and BGM, a Slight Risk was
    introduced. Additionally, MPD #962 in association with this event
    has been issued through 21Z.

    Elsewhere, no further changes were needed in terms of the MRGL Risk
    throughout much of the country. Thought was given toward an upgrade
    in northern AR, where an influx of moisture intersecting with the
    Ozarks could result in heavier rain throughout the afternoon.
    Ultimately, an upgrade was not needed mostly due to the very high
    FFGs, which rainfall will struggle to meet. Isolated flash flooding
    will remain a concern, however.

    Ongoing convection in Minnesota is set to continue over the next
    several hours, and has already brought spots of 1"/hr rates.
    7-8/C/km lapse rates, solid instability (~2000J/kg), and PWATs
    around 1.5" will continue to support heavy rainfall. Storm motion
    will be quite progressive, however, and 1hr FFGs remain above 1.5".
    Given that, keeping a MRGL area was sufficient. Isolated instances
    of flash flooding remain possible however, and as such, MPD #963
    has been issued through 2130Z.

    Blanco-Alcala

    Previous Discussion...

    Marginal Risks for excessive rainfall cover large portions of the
    country from the Southwest through much of the eastern half of the
    country. The Marginal was expanded to include much of Oklahoma and
    north Texas, as well as expanded through Louisiana and portions of
    the central Gulf Coast, as well as much of Florida.

    Abundant deep tropical moisture is in place across much of the
    Southeast and up the Eastern Seaboard. Forcings remain mesoscale,
    as the synoptic pattern with a trough generally along the northern
    tier of states generally is not overlapping most of the deepest
    moisture. Thus, where there is enough forcing, there's a lack of
    moisture, and in large swaths of the country where there's plenty
    of moisture, a lack of a defining synoptic feature to provide
    forcing will likely mean any storms will be reliant on smaller
    mesoscale features such as local terrain, cold pools, sea breezes
    etc. to get them going.

    Due to a lack of defining features overall, large Marginals remain
    the most prudent forecast. However, given the aforementioned deep
    tropical moisture over much of the country, it's quite feasible
    that there will be Slight Risk levels of impacts wherever the
    storms can interact with each other in a positive way. This appears
    most likely on Friday across portions of Arkansas, where the deep
    tropical moisture will run into the terrain of the Ozarks, and the
    base of the distant upper level trough could provide a bit of
    organization to the convection. That said, the very dry soils from
    the lack of rainfall across the state in recent days will make
    Slight level impacts difficult to attain.

    From eastern Ohio through much of Pennsylvania and southern New
    York, there too will have some minimal amount of forcing from weak
    upper level shortwaves running over the abundant summertime
    moisture in place across much of the east. Here too there is a
    higher risk of Slight Risk level impacts, in part due to low FFGs.
    Convection across this region looks to be quite progressive though,
    so it will likely take topographic enhancement in localized areas
    to produce enough rain to produce widely scattered instances of
    flash flooding. These should be few and far between enough to not
    need a Slight there for now.

    Wegman


    Day 2
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR THE
    SOUTHWEST, PORTIONS OF THE MIDWEST, AND MUCH OF THE EASTERN
    SEABOARD...

    Monsoonal moisture across the Southwest will continue on Saturday,
    especially across Arizona. As usual, the greatest rainfall will be
    along the Mexican border where the Gulf of California's influence
    is greatest, as well as along the Mogollon Rim. There appears to be
    little rain in between in the populated areas. Lack of signal for
    more organized heavy rain should preclude a Slight Risk upgrade.

    Across the Midwest, specifically Iowa, an overnight Saturday night
    MCS is expected to impact much of Iowa and small portions of the
    neighboring states. While guidance has come into better agreement
    on the areas likely to be affected, there remains a broad variety
    of solutions as to how much rain will fall across much of central
    and eastern Iowa. Thus, for now the area remains in a Marginal, but
    will continue to be monitored for a Slight risk upgrade with future
    updates.

    Signals for heavy rain across much of the Eastern Seaboard remain
    very diffuse again on Saturday. Similar to Friday, there remains
    plentiful moisture all up and down the Atlantic coast. Somewhat
    better forcing from a negatively tilted trough north of the Great
    Lakes should allow for more widespread storms, but they will remain
    quite progressive. Further south, there will be more moisture, but
    a lack of forcing. Most of the heaviest rains look to be from north
    Florida through coastal South Carolina.

    Wegman


    Day 3
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER MIDWEST AND UPPER MISSISSIPPI VALLEY...

    ...Upper Midwest...

    Multiple rounds of storms are expected on Sunday across portions of
    the upper Midwest, specifically from the southeast corner of
    Minnesota southeast through northern Indiana. With plentiful
    moisture from an LLJ originating from the Gulf being advected
    northward into the storms, there is little reason to see why the
    storms won't be able to backbuild and train both with the morning
    convection with an MCS, and then secondarily with late afternoon
    through the Sunday night convection across these same areas. Since
    guidance has come into better agreement, even better than Days 1
    and 2, a Slight Risk upgrade was introduced with this update.

    ...Elsewhere...

    Elsewhere, the Southwest monsoon will continue to promote afternoon
    and evening convective development into the 4 Corners region, and
    southwesterly moisture advection into the southern Appalachians
    could also provide a focus (due to terrain) for afternoon and
    evening storms. As on prior days, widespread widely scattered
    convection is likely all across the Southeast Sunday afternoon and
    evening. Should storms merge over urban areas, then flash flooding
    is quite possible outside of the drawn Marginal Risk area. Thus,
    it's probable additional expansions and changes will be needed over
    the coming days into the Southeast.

    Wegman


    Day 4 and Day 5

    Valid 12Z Mon Aug 10 2026 - 12Z Wed Aug 12 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN AND NEAR
    NORTHERN INDIANA...

    ...Great Lakes/Midwest...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    Hudson Bay. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~1.75" ahead of each set
    of shortwaves and low-level confluence is expected. When looking
    at the ingredients, organized convection looks most likely south of
    the Great Lakes within eastern portions of the Corn Belt, where
    hourly rain amounts to 2.5" are possible. Due to a bit better
    agreement in the guidance, and the southward trends towards where
    conceptual models would have placed a Slight Risk 24 hours ago,
    went ahead and added a Slight Risk for areas in and around northern
    IN both days. While there is still some possibility of further
    southward trends, this trend may materialize more as a later
    southward expansion as we get closer to the event.

    ..Southwest...
    Broad Marginal Risk areas exist both days early to mid next week across portions of the Southwest, Rockies, and Great Basin. While there
    continues to be low confidence with the details, locally heavy
    rains with the potential of 2" an hour amounts and isolated runoff
    issues will continue in the axis of above average PW values
    expected across this area. As usual, urban areas, arroyos/dry
    washes, box canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!6Cw93V9HjdvOsfVgB1q278eIRDqVV082ZzSSxCLpiyJxAhh1JABtsun8_qWdGhd1RWWI4ysoHBZOkOEoG-HmZo7MbFY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!6Cw93V9HjdvOsfVgB1q278eIRDqVV082ZzSSxCLpiyJxAhh1JABtsun8_qWdGhd1RWWI4ysoHBZOkOEoG-HmSXEpCBw$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!6Cw93V9HjdvOsfVgB1q278eIRDqVV082ZzSSxCLpiyJxAhh1JABtsun8_qWdGhd1RWWI4ysoHBZOkOEoG-Hm1zdUC1w$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 8 07:31:22 2026
    FOUS30 KWBC 080730
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    330 AM EDT Sat Aug 8 2026

    Day 1
    Valid 12Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE LOW COUNTRY
    OF SOUTH CAROLINA AND GEORGIA...

    ...Low Country...

    An area of disturbed weather moving up the Atlantic coast off of
    north Florida is expected to impact the Low Country of South
    Carolina and Georgia as soon as in the next few hours. Deep
    tropical moisture with PWATs exceeding 2 inches accompany the
    associated showers and thunderstorms. Thus, the storms will be
    quite capable of very heavy rainfall in the affected areas. The big
    question in the guidance is how far inland this activity will
    reach. Much of the guidance suggests it will impact just the
    immediate coastal areas from Charleston south through Hilton Head
    and Savannah. Others are struggling to even show that...keeping
    most of the associated rainfall this morning offshore. Given this
    discrepancy, the inherited Slight was maintained, albeit shrunk to
    the immediate coast from about halfway down the South Carolina
    coast to halfway down the Georgia coast. Urban and small stream
    flooding in Charleston and Savannah will be most likely, as opposed
    to flooding in the areas in between. Flooding impacts will be
    worsened at high tide. Fortunately, high tide is around 4-5am, and
    the greatest likelihood of showers and storms impacting the Slight
    Risk area will be in the late morning around low tide, which should
    mitigate the flooding threat significantly.

    ...Other Marginals across the Country...

    Marginal Risks cover nearly the entire Eastern Seaboard, much of
    the Southeast, and relatively small areas of the Upper Midwest and
    Southwest. For the East, the same pocket of deep tropical moisture
    hosting the aforementioned area of disturbed weather off the
    Atlantic coast of the Southeast will support widely scattered
    showers and storms from the lower Mississippi Valley up the length
    of the Appalachians and into the Northeast. This will occur this
    afternoon at peak heating. Multiple rounds of storms may impact
    portions of Arkansas and Mississippi as well as into New Hampshire
    and western Maine today. In both these areas, slightly better
    forcing along the moisture gradient will support additional storms
    impacting these areas compared to the rest of the Eastern Seaboard.
    Both areas also feature drier than normal soils, which should help
    to temper any flooding to isolated instances. Thus, while Slights
    were considered, neither were upgraded for this reason.

    The Marginal in the Midwest was trimmed from the southwest, an
    unusual direction. Guidance continues to trend drier and further
    north and east, so the Marginal was adjusted accordingly. A Slight
    risk upgrade in this area is no longer being considered.

    Monsoonal moisture will continue to impact portions of the
    Southwest, following the Mogollon Rim, with broader southwesterly
    flow allowing a few showers and storms to impact portions of
    northeastern New Mexico. Any showers and storms will be few and far
    between, so the flash flooding threat there will be isolated.

    Wegman


    Day 2
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER GREAT LAKES AND UPPER MISSISSIPPI VALLEY...

    ...Upper Great Lakes & Mississippi Valley...

    A series of disturbances moving eastward along the southern
    periphery of a large upper low well into Canada will result in
    multiple rounds of storms on Sunday across the Slight Risk area.
    The first will be the remnants of an MCS that will start the day in
    far southeastern Minnesota, and will then track south and east
    along the Wisconsin/Illinois border. The storms in general should
    be pretty fast moving, so it's unlikely too many flooding impacts
    will be seen from this feature alone. However, what it will do is
    prime the soils by moistening them up for the later round.

    The second round will form at the nose of a developing low level
    jet Sunday night. The storms will follow the greatest instability,
    which will mean the storms will track southward. The should be
    significantly slower moving, and much more widespread compared to
    the first round earlier in the day. The widely scattered instances
    of flash flooding associated with the Slight will be mostly
    confined to this Sunday night period. Urban and small stream
    impacts in and around Chicago and possibly Milwaukee and Detroit
    are the most likely impacts.

    ...Marginals Elsewhere...

    As on previous days, deep tropical moisture across the Southeast
    will favor another round of afternoon showers and storms from
    northern Mississippi into the southern Appalachians. Flash flooding
    will likely be confined to areas where the storms are most
    persistent (northern Mississippi), or where terrain helps funnel
    the rainwater (southern Appalachians). Generally the storms, while
    scattered, should be disorganized, so a Marginal was maintained for
    now, though targeted Slights are certainly possible in the coming
    days.

    The monsoon will continue across the 4 Corners region on Sunday.
    While a bit more widespread over the Southwest, most organized
    convection will be very limited, so few changes to the inherited
    Marginal Risk were needed.

    Wegman


    Day 3
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE GREAT LAKES AND SOUTHEASTERN ARIZONA...

    ...Great Lakes...

    A large upper level low well over Canada will spin a strong
    shortwave across the Great Lakes on Monday. Deep tropical moisture
    will be drawn northward from the reservoir of moisture over the
    Southeast, allowing for widespread showers and thunderstorms,
    generally from Chicago east to portions of the Central
    Appalachians. The inherited Slight was expanded to the east, to
    includes much of eastern Ohio, western Pennsylvania, including
    Pittsburgh, and far western New York, including Buffalo with this
    update.

    ...Southeastern Arizona...

    Deep tropical moisture moving up the Gulf of California will
    intrude into southeastern Arizona on Monday, with PWATs exceeding
    1.5 inches in many areas. A thermal low due to the strong high
    aloft will support widespread shower and thunderstorm activity,
    particularly along the Mexican border and up I-19 from Nogales
    through Tucson. This corridor is both highly flood prone, has seen
    numerous days of widely scattered flash flooding in recent days,
    and is right in line for additional widespread convection Monday
    afternoon. There is considerable uncertainty moving west up I-10
    beyond Tucson, so the introduced Slight is primarily for this most
    vulnerable corridor, where a higher-end Slight in in place.

    Wegman


    Day 4 and Day 5

    Valid 12Z Tue Aug 11 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    EASTERN CORN BELT & UPPER OHIO VALLEY...

    ...Great Lakes/Northern and Central Plains/Midwest/Upper Ohio
    Valley...
    Early to mid next week, broad cyclonic flow expected to
    persist across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low
    moving from Hudson Bay across Quebec. A frontal boundary will lie
    along the southern periphery of this broad trough. Embedded
    shortwaves in this broad cyclonic flow will accentuate lift in the
    vicinity of this front where PW values are expected to rise to
    ~1.75" ahead of each set of shortwaves and low- level confluence is
    expected. When looking at the ingredients, organized convection
    looks most likely south of the Great Lakes within eastern portions
    of the Corn Belt Tuesday into Tuesday night and across the Upper
    Ohio Valley Wednesday into Wednesday night, where hourly rain
    amounts to 2.5" are possible. There is significant disagreement on Wednesday/Wednesday night on where a heavy rain axis would be
    across the eastern Corn Belt/Midwest, so for the time being, no
    Slight Risk has been drawn/assigned. Recent guidance nudged north,
    so the Slight Risk area on Tuesday was shifted similarly. For Wednesday/Wednesday night, a Slight Risk area was introduced for WV
    where the guidance has relatively good agreement on the potential
    for heavy rainfall within areas of significant relief.

    ..Southwest/Colorado...
    Broad Marginal Risk areas exist early to mid next week across
    portions of the Southwest, Rockies, and Great Basin. Ridging/warm
    700 hPa temperatures shifts north and weakens/lowers somewhat
    across the Intermountain West, which opens the door to broader
    convective development in the Southwest at some point, potentially
    next Wednesday, where above average precipitable water values
    persist over the next five days with minimal day to day variation.
    While there continues to be low confidence with the details,
    locally heavy rains with the potential of 2" an hour amounts could
    become more expansive Wednesday. A Slight Risk cannot be ruled out
    across portions of this area as we get closer to the days in
    question. As usual, urban areas, arroyos/dry washes, box/slot
    canyons, and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_pYaUKLhMXnXgLRPNji4WH3ai5k2kAg2M4zvT2xFYSy2W-mIH3yc-PKCwE386pxmynOY_b3ws308Y-q9T0U3BFZyWXw$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_pYaUKLhMXnXgLRPNji4WH3ai5k2kAg2M4zvT2xFYSy2W-mIH3yc-PKCwE386pxmynOY_b3ws308Y-q9T0U3seFC1dQ$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_pYaUKLhMXnXgLRPNji4WH3ai5k2kAg2M4zvT2xFYSy2W-mIH3yc-PKCwE386pxmynOY_b3ws308Y-q9T0U3iLyA8c8$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 8 15:34:54 2026
    FOUS30 KWBC 081534
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1134 AM EDT Sat Aug 8 2026

    Day 1
    Valid 16Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE LOW COUNTRY
    OF SOUTH CAROLINA AND GEORGIA...

    ...Low Country...

    16Z Update: Weak disturbance is analyzed off the coast of GA with
    the northern periphery of the inverted trough nosing into southern
    SC with the radar depiction over Charleston finally showing some
    activity sneaking ashore. The setup remains conducive for locally
    heavy rainfall as PWATs remains ~2 standard deviations above normal
    within the immediate coastal plain of GA and southern SC. The
    cutoff on the northern edge of the disturbance is sharp, however,
    as noted via a solid ~0.7" difference in area PWATs between the
    12z KJAX (2.42") and KCHS (1.74") soundings this morning associated
    with the disturbance. Mesoanalysis does show the more prolific
    tongue of higher PWATs slowly advecting northward into the
    Charleston area, but the greater PWAT anomalies are still forecast
    to be closer to Hilton Head down into coastal GA where the heaviest
    rain is more likely to occur.

    Latest HREF probs remain more prolific for localized 3+ inch totals
    between Brunswick up through Savannah and nudging into Hilton Head.
    Probs fall off as you move north, so it could be a case where
    Charleston proper misses out on the worst, but it'll still be very
    close, so maintained the city in the SLGT risk, but just barely as
    of this latest update. Expectation is for the heaviest rain to
    occur now until 21z as the disturbance is forecast to shift
    northeast and the rain chances dwindle heading into the evening. As
    a result, expectation is for the SLGT risk to likely fall off to a
    nil during the 01z update, so the primary period of concern will be
    over the next 4-6 hrs.

    Kleebauer

    ...Other Marginals across the Country...

    16Z Update: The broad MRGL risk extending from New England into the
    Lower Mississippi Valley was relatively unchanged as a prominent
    deep moist airmass with widespread elevated instability will
    maintain an environment conducive for locally heavy rainfall with
    rates between 1-2"/hr pretty much anywhere within the
    aforementioned area. The most notable adjustments were made over
    southern VA where the MRGL was expanded to include a bit more of
    the I-95 corridor between Fredericksburg through Richmond, down
    into Emporia. Heaviest rainfall threat will likely situate west of
    I-85 in VA, but some of the CAMs are a bit more aggressive towards
    Richmond, so wanted to include the urban center as this area of VA
    is more susceptible to flash flood concerns due to the urban
    footprint. New England remains generally unchanged as well,
    although did trim a touch more of southeastern MA out of the MRGL
    given the latest trends of convection expected to be a bit more
    northwest than originally progged.

    The Southwest U.S. will continue to see Monsoonal moisture play a
    role in the daily convective regime with the expansion of higher
    moisture northward into the Great Basin for today. Latest CAMs are
    privy for a bit more thunderstorm coverage into NV for this
    afternoon and early evening before waning after sunset. The MRGL
    risk was expanded a bit further west to encompass the trend,
    however, did maintain the nil into Vegas proper as the threat looks
    to avoid the main urban area, but will be something to watch if
    any outflows can buck the trend and sneak into the area from the
    east. Otherwise, the heat remains the talking point for the area
    with the ridge overhead. Primary concerns will be those areas in
    southwestern UT, northern AZ, and the Mogollon Rim due to the slot
    canyons and susceptible grounds for run off.

    Kleebauer

    ..Previous Discussion..

    Marginal Risks cover nearly the entire Eastern Seaboard, much of
    the Southeast, and relatively small areas of the Upper Midwest and
    Southwest. For the East, the same pocket of deep tropical moisture
    hosting the aforementioned area of disturbed weather off the
    Atlantic coast of the Southeast will support widely scattered
    showers and storms from the lower Mississippi Valley up the length
    of the Appalachians and into the Northeast. This will occur this
    afternoon at peak heating. Multiple rounds of storms may impact
    portions of Arkansas and Mississippi as well as into New Hampshire
    and western Maine today. In both these areas, slightly better
    forcing along the moisture gradient will support additional storms
    impacting these areas compared to the rest of the Eastern Seaboard.
    Both areas also feature drier than normal soils, which should help
    to temper any flooding to isolated instances. Thus, while Slights
    were considered, neither were upgraded for this reason.

    The Marginal in the Midwest was trimmed from the southwest, an
    unusual direction. Guidance continues to trend drier and further
    north and east, so the Marginal was adjusted accordingly. A Slight
    risk upgrade in this area is no longer being considered.

    Monsoonal moisture will continue to impact portions of the
    Southwest, following the Mogollon Rim, with broader southwesterly
    flow allowing a few showers and storms to impact portions of
    northeastern New Mexico. Any showers and storms will be few and far
    between, so the flash flooding threat there will be isolated.

    Wegman


    Day 2
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER GREAT LAKES AND UPPER MISSISSIPPI VALLEY...

    ...Upper Great Lakes & Mississippi Valley...

    A series of disturbances moving eastward along the southern
    periphery of a large upper low well into Canada will result in
    multiple rounds of storms on Sunday across the Slight Risk area.
    The first will be the remnants of an MCS that will start the day in
    far southeastern Minnesota, and will then track south and east
    along the Wisconsin/Illinois border. The storms in general should
    be pretty fast moving, so it's unlikely too many flooding impacts
    will be seen from this feature alone. However, what it will do is
    prime the soils by moistening them up for the later round.

    The second round will form at the nose of a developing low level
    jet Sunday night. The storms will follow the greatest instability,
    which will mean the storms will track southward. The should be
    significantly slower moving, and much more widespread compared to
    the first round earlier in the day. The widely scattered instances
    of flash flooding associated with the Slight will be mostly
    confined to this Sunday night period. Urban and small stream
    impacts in and around Chicago and possibly Milwaukee and Detroit
    are the most likely impacts.

    ...Marginals Elsewhere...

    As on previous days, deep tropical moisture across the Southeast
    will favor another round of afternoon showers and storms from
    northern Mississippi into the southern Appalachians. Flash flooding
    will likely be confined to areas where the storms are most
    persistent (northern Mississippi), or where terrain helps funnel
    the rainwater (southern Appalachians). Generally the storms, while
    scattered, should be disorganized, so a Marginal was maintained for
    now, though targeted Slights are certainly possible in the coming
    days.

    The monsoon will continue across the 4 Corners region on Sunday.
    While a bit more widespread over the Southwest, most organized
    convection will be very limited, so few changes to the inherited
    Marginal Risk were needed.

    Wegman


    Day 3
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE GREAT LAKES AND SOUTHEASTERN ARIZONA...

    ...Great Lakes...

    A large upper level low well over Canada will spin a strong
    shortwave across the Great Lakes on Monday. Deep tropical moisture
    will be drawn northward from the reservoir of moisture over the
    Southeast, allowing for widespread showers and thunderstorms,
    generally from Chicago east to portions of the Central
    Appalachians. The inherited Slight was expanded to the east, to
    includes much of eastern Ohio, western Pennsylvania, including
    Pittsburgh, and far western New York, including Buffalo with this
    update.

    ...Southeastern Arizona...

    Deep tropical moisture moving up the Gulf of California will
    intrude into southeastern Arizona on Monday, with PWATs exceeding
    1.5 inches in many areas. A thermal low due to the strong high
    aloft will support widespread shower and thunderstorm activity,
    particularly along the Mexican border and up I-19 from Nogales
    through Tucson. This corridor is both highly flood prone, has seen
    numerous days of widely scattered flash flooding in recent days,
    and is right in line for additional widespread convection Monday
    afternoon. There is considerable uncertainty moving west up I-10
    beyond Tucson, so the introduced Slight is primarily for this most
    vulnerable corridor, where a higher-end Slight in in place.

    Wegman


    Day 4 and Day 5

    Valid 12Z Tue Aug 11 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    EASTERN CORN BELT & UPPER OHIO VALLEY...

    ...Great Lakes/Northern and Central Plains/Midwest/Upper Ohio
    Valley...
    Early to mid next week, broad cyclonic flow expected to
    persist across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low
    moving from Hudson Bay across Quebec. A frontal boundary will lie
    along the southern periphery of this broad trough. Embedded
    shortwaves in this broad cyclonic flow will accentuate lift in the
    vicinity of this front where PW values are expected to rise to
    ~1.75" ahead of each set of shortwaves and low- level confluence is
    expected. When looking at the ingredients, organized convection
    looks most likely south of the Great Lakes within eastern portions
    of the Corn Belt Tuesday into Tuesday night and across the Upper
    Ohio Valley Wednesday into Wednesday night, where hourly rain
    amounts to 2.5" are possible. There is significant disagreement on Wednesday/Wednesday night on where a heavy rain axis would be
    across the eastern Corn Belt/Midwest, so for the time being, no
    Slight Risk has been drawn/assigned. Recent guidance nudged north,
    so the Slight Risk area on Tuesday was shifted similarly. For Wednesday/Wednesday night, a Slight Risk area was introduced for WV
    where the guidance has relatively good agreement on the potential
    for heavy rainfall within areas of significant relief.

    ..Southwest/Colorado...
    Broad Marginal Risk areas exist early to mid next week across
    portions of the Southwest, Rockies, and Great Basin. Ridging/warm
    700 hPa temperatures shifts north and weakens/lowers somewhat
    across the Intermountain West, which opens the door to broader
    convective development in the Southwest at some point, potentially
    next Wednesday, where above average precipitable water values
    persist over the next five days with minimal day to day variation.
    While there continues to be low confidence with the details,
    locally heavy rains with the potential of 2" an hour amounts could
    become more expansive Wednesday. A Slight Risk cannot be ruled out
    across portions of this area as we get closer to the days in
    question. As usual, urban areas, arroyos/dry washes, box/slot
    canyons, and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!_WB1JeQVFvnZhwEHVnbE7iey4csJRzY7VgNtuRn2D1YikPVdlEJwPCbahLa8-L7altZR8ULlTK-iZ0E5NT6vpomY8hA$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!_WB1JeQVFvnZhwEHVnbE7iey4csJRzY7VgNtuRn2D1YikPVdlEJwPCbahLa8-L7altZR8ULlTK-iZ0E5NT6vytkD3rk$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!_WB1JeQVFvnZhwEHVnbE7iey4csJRzY7VgNtuRn2D1YikPVdlEJwPCbahLa8-L7altZR8ULlTK-iZ0E5NT6vMIlKQys$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sat Aug 8 19:57:58 2026
    FOUS30 KWBC 081957
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    357 PM EDT Sat Aug 8 2026

    Day 1
    Valid 16Z Sat Aug 08 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE LOW COUNTRY
    OF SOUTH CAROLINA AND GEORGIA...

    ...Low Country...

    16Z Update: Weak disturbance is analyzed off the coast of GA with
    the northern periphery of the inverted trough nosing into southern
    SC with the radar depiction over Charleston finally showing some
    activity sneaking ashore. The setup remains conducive for locally
    heavy rainfall as PWATs remains ~2 standard deviations above normal
    within the immediate coastal plain of GA and southern SC. The
    cutoff on the northern edge of the disturbance is sharp, however,
    as noted via a solid ~0.7" difference in area PWATs between the
    12z KJAX (2.42") and KCHS (1.74") soundings this morning associated
    with the disturbance. Mesoanalysis does show the more prolific
    tongue of higher PWATs slowly advecting northward into the
    Charleston area, but the greater PWAT anomalies are still forecast
    to be closer to Hilton Head down into coastal GA where the heaviest
    rain is more likely to occur.

    Latest HREF probs remain more prolific for localized 3+ inch totals
    between Brunswick up through Savannah and nudging into Hilton Head.
    Probs fall off as you move north, so it could be a case where
    Charleston proper misses out on the worst, but it'll still be very
    close, so maintained the city in the SLGT risk, but just barely as
    of this latest update. Expectation is for the heaviest rain to
    occur now until 21z as the disturbance is forecast to shift
    northeast and the rain chances dwindle heading into the evening. As
    a result, expectation is for the SLGT risk to likely fall off to a
    nil during the 01z update, so the primary period of concern will be
    over the next 4-6 hrs.

    Kleebauer

    ...Other Marginals across the Country...

    16Z Update: The broad MRGL risk extending from New England into the
    Lower Mississippi Valley was relatively unchanged as a prominent
    deep moist airmass with widespread elevated instability will
    maintain an environment conducive for locally heavy rainfall with
    rates between 1-2"/hr pretty much anywhere within the
    aforementioned area. The most notable adjustments were made over
    southern VA where the MRGL was expanded to include a bit more of
    the I-95 corridor between Fredericksburg through Richmond, down
    into Emporia. Heaviest rainfall threat will likely situate west of
    I-85 in VA, but some of the CAMs are a bit more aggressive towards
    Richmond, so wanted to include the urban center as this area of VA
    is more susceptible to flash flood concerns due to the urban
    footprint. New England remains generally unchanged as well,
    although did trim a touch more of southeastern MA out of the MRGL
    given the latest trends of convection expected to be a bit more
    northwest than originally progged.

    The Southwest U.S. will continue to see Monsoonal moisture play a
    role in the daily convective regime with the expansion of higher
    moisture northward into the Great Basin for today. Latest CAMs are
    privy for a bit more thunderstorm coverage into NV for this
    afternoon and early evening before waning after sunset. The MRGL
    risk was expanded a bit further west to encompass the trend,
    however, did maintain the nil into Vegas proper as the threat looks
    to avoid the main urban area, but will be something to watch if
    any outflows can buck the trend and sneak into the area from the
    east. Otherwise, the heat remains the talking point for the area
    with the ridge overhead. Primary concerns will be those areas in
    southwestern UT, northern AZ, and the Mogollon Rim due to the slot
    canyons and susceptible grounds for run off.

    Kleebauer

    ..Previous Discussion..

    Marginal Risks cover nearly the entire Eastern Seaboard, much of
    the Southeast, and relatively small areas of the Upper Midwest and
    Southwest. For the East, the same pocket of deep tropical moisture
    hosting the aforementioned area of disturbed weather off the
    Atlantic coast of the Southeast will support widely scattered
    showers and storms from the lower Mississippi Valley up the length
    of the Appalachians and into the Northeast. This will occur this
    afternoon at peak heating. Multiple rounds of storms may impact
    portions of Arkansas and Mississippi as well as into New Hampshire
    and western Maine today. In both these areas, slightly better
    forcing along the moisture gradient will support additional storms
    impacting these areas compared to the rest of the Eastern Seaboard.
    Both areas also feature drier than normal soils, which should help
    to temper any flooding to isolated instances. Thus, while Slights
    were considered, neither were upgraded for this reason.

    The Marginal in the Midwest was trimmed from the southwest, an
    unusual direction. Guidance continues to trend drier and further
    north and east, so the Marginal was adjusted accordingly. A Slight
    risk upgrade in this area is no longer being considered.

    Monsoonal moisture will continue to impact portions of the
    Southwest, following the Mogollon Rim, with broader southwesterly
    flow allowing a few showers and storms to impact portions of
    northeastern New Mexico. Any showers and storms will be few and far
    between, so the flash flooding threat there will be isolated.

    Wegman


    Day 2
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER GREAT LAKES AND UPPER MISSISSIPPI VALLEY...

    ...Upper Great Lakes & Mississippi Valley...

    20Z Update: The overall pattern remains favorable for a multi-
    round convective episode during the D2 period with the area of
    greatest focus likely to materialize over northern IL and southern
    WI and points east with the Chicago area the most notable area of
    potential impacts. There's a growing concern for a more locally
    significant flash flood prospect for the Chicago metro, including
    adjacent suburbs with the nocturnal convective maturation that's
    expected on Sunday night into early Monday morning. Warm front
    positioning and a strengthening 850mb LLJ will be key components in
    the threat over the area, one that is more susceptible to flash
    flooding thanks to the broad urban sprawl that extends from
    southern Lake Michigan and encompasses the entire area spanning
    northeast IL through northwestern IN. 12z HREF neighborhood
    probabilities for >3" are upwards of 60-80% currently for the above
    region, including the center of Chicago proper where high run off
    capabilities are notorious for local flooding hazards. There are
    even some notable >5" probs of 40-60% within the area spanning the
    western and northern Chicago suburbs down through the center of
    Chicago proper, a testament to the potential in this setup, and a
    general agreement from the CAMs on the positioning of the heavier
    rainfall.

    Ensemble mean QPF is greater than 2" over much of the
    Chicago metro, a signal that typically favors at least scattered
    flash flooding with perhaps widespread flash flood concerns if
    everything comes together perfectly. The back-building scenario
    with the setup is the reason for such a strong mean QPF signature,
    correlating well with the strong low-level convergence regime and
    locally backed flow between sfc-700mb positioned near the warm
    front. Ultimately, that frontal positioning will be pivotal in
    where the heaviest rainfall will materialize, and current
    indications is it will be within that zone bisecting northern IL
    into northern IN by the second half of the period. In this case,
    there is enough of a signal and general consensus on a high-end
    SLGT risk forecast for that zone with emphasis on northeast IL and
    northwest IN given the elevated probabilities for >3" of rainfall.

    Kleebauer

    ..Previous Discussion..

    A series of disturbances moving eastward along the southern
    periphery of a large upper low well into Canada will result in
    multiple rounds of storms on Sunday across the Slight Risk area.
    The first will be the remnants of an MCS that will start the day in
    far southeastern Minnesota, and will then track south and east
    along the Wisconsin/Illinois border. The storms in general should
    be pretty fast moving, so it's unlikely too many flooding impacts
    will be seen from this feature alone. However, what it will do is
    prime the soils by moistening them up for the later round.

    The second round will form at the nose of a developing low level
    jet Sunday night. The storms will follow the greatest instability,
    which will mean the storms will track southward. The should be
    significantly slower moving, and much more widespread compared to
    the first round earlier in the day. The widely scattered instances
    of flash flooding associated with the Slight will be mostly
    confined to this Sunday night period. Urban and small stream
    impacts in and around Chicago and possibly Milwaukee are the most
    likely impacts.

    Wegman

    ...Marginals Elsewhere...

    20Z Update: Only minor adjustments made to the remaining MRGL risks
    across both the Eastern and Southwestern U.S. Primary change was a
    narrow expansion of the MRGL to include the VA Tidewater and
    southern VA as guidance insists on another round of convection with
    rates between 1-2"/hr impacting these areas by Sunday afternoon and
    early evening before dwindling with the loss of diurnal
    instability after sunset. Southwestern U.S. remains on track for
    prevalent monsoonal moisture making its presence known across AZ,
    extending northward through the Great Basin.

    Kleebauer

    ..Previous Discussion..

    As on previous days, deep tropical moisture across the Southeast
    will favor another round of afternoon showers and storms from
    northern Mississippi into the southern Appalachians. Flash flooding
    will likely be confined to areas where the storms are most
    persistent (northern Mississippi), or where terrain helps funnel
    the rainwater (southern Appalachians). Generally the storms, while
    scattered, should be disorganized, so a Marginal was maintained for
    now, though targeted Slights are certainly possible in the coming
    days.

    The monsoon will continue across the 4 Corners region on Sunday.
    While a bit more widespread over the Southwest, most organized
    convection will be very limited, so few changes to the inherited
    Marginal Risk were needed.

    Wegman


    Day 3
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE GREAT LAKES AND SOUTHEASTERN ARIZONA...

    ...Great Lakes...

    20Z Update: The setup for D3 remains pretty consistent in run-to-
    run continuity with the highlight of heavy rainfall extending over
    the southern Great Lakes and northern Ohio Valley into western PA
    and the adjacent WV Highlands. A lot of the setup is contingent on
    the behavior of any complexes that materialize upstream over the
    Midwest and migrate east through the forecast. Looks like activity
    will be prone to producing rates upwards of 2"/hr, locally higher
    given a robust moist and unstable airmass present on the northern
    periphery of a broad ridge to the south, and the southern
    inflection of a sprawling ULL over Canada. In any case, the setup
    is textbook for an area of above normal convective chances that
    will take advantage of both a favorable thermodynamic and kinematic
    environment as the positioning of the jet will favor large scale
    ascent across much of the Great Lakes and Ohio Valley into the
    Appalachian front. As of now, the only change from the previous
    forecast was to expand the SLGT a bit further south into WV and
    east to bank up against the western slopes of the Appalachians in
    PA. Will be monitoring this setup closely as a high-end SLGT is not
    out of the realm of possibility considering all of the above
    factors, as well as the addition of terrain influences on the
    eastern extent of the current SLGT.

    Kleebauer

    ..Previous Discussion..

    A large upper level low well over Canada will spin a strong
    shortwave across the Great Lakes on Monday. Deep tropical moisture
    will be drawn northward from the reservoir of moisture over the
    Southeast, allowing for widespread showers and thunderstorms,
    generally from Chicago east to portions of the Central
    Appalachians. The inherited Slight was expanded to the east, to
    includes much of eastern Ohio, western Pennsylvania, including
    Pittsburgh, and far western New York, including Buffalo with this
    update.

    Wegman

    ...Southeastern Arizona...

    20Z Update: A favorable setup for heavy rainfall across
    southeastern AZ exists within a majority of guidance with ensemble
    mean QPF pushing >1" over much of the terrain focused within
    eastern Pima, Santa Cruz, and Cochise counties along and south of
    I-10. The previous high-end SLGT forecast continues to have merit
    with some of the deterministic outputs pushing local totals up near
    3", a threshold that would undoubtedly cause locally significant
    flash flood concerns within the aforementioned areas. Areas like
    the Huachuca mountains over to I-19 are the most likely areas to
    see significant rainfall in the setup. As we move closer to CAMs
    range, it will be an area to monitor for potential further upgrades
    if the signal becomes more pronounced in the general magnitude of
    the rainfall forecast. For now, the SLGT remains with the
    highlighted area across the southern tier the noted high-end SLGT
    risk.

    Kleebauer

    ..Previous Discussion..

    Deep tropical moisture moving up the Gulf of California will
    intrude into southeastern Arizona on Monday, with PWATs exceeding
    1.5 inches in many areas. A thermal low due to the strong high
    aloft will support widespread shower and thunderstorm activity,
    particularly along the Mexican border and up I-19 from Nogales
    through Tucson. This corridor is both highly flood prone, has seen
    numerous days of widely scattered flash flooding in recent days,
    and is right in line for additional widespread convection Monday
    afternoon. There is considerable uncertainty moving west up I-10
    beyond Tucson, so the introduced Slight is primarily for this most
    vulnerable corridor, where a higher-end Slight in in place.

    Wegman


    Day 4 and Day 5

    Valid 12Z Tue Aug 11 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY...

    20z Update: Still on track for an excessive rainfall threat
    Tuesday from portions of IL/IN into WV. Some uncertainty on the
    exact latitude of the threat, and not seeing any strong trend in
    todays models. Thus only made a small southward expansion of the
    Slight risk to account for the consistent AIFS, which has been on
    the southern end of the model envelope. We were able to cut back
    on the Marginal risk over the Northeast. Only the GFS keeps
    robust convection across this region...with the
    ECMWF/ECENS/CMC/AIGFS all showing drier air over the northeast and
    the better convective threat farther southwest.

    On day 5 (Wednesday) a heavy rainfall threat will continue on the
    periphery of the southern U.S. ridge, with convection from the
    Southwest into the central/northern Plains, and then extending
    southeastward into portions of the OH and TN valley. The inherited
    Slight risk over WV was made a bit larger to include some of
    eastern KY and southern OH. Overall confidence in this area is low,
    as seeing divergence in model QPF solutions. Think there will be
    an excessive rainfall threat, but could easily see this Slight
    risk area shift in location and/or size over the coming days.
    Still seeing a model signal for organized convection over portions
    of SD/NE, but enough uncertainty on those details to keep a
    Marginal for now. The Southwest still look to be more active
    Wednesday, but spatial confidence too low to introduce any slight
    risk area at this time.

    Chenard

    ...Previous Discussion...

    ...Great Lakes/Northern and Central Plains/Midwest/Upper Ohio
    Valley...
    Early to mid next week, broad cyclonic flow expected to
    persist across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low
    moving from Hudson Bay across Quebec. A frontal boundary will lie
    along the southern periphery of this broad trough. Embedded
    shortwaves in this broad cyclonic flow will accentuate lift in the
    vicinity of this front where PW values are expected to rise to
    ~1.75" ahead of each set of shortwaves and low- level confluence is
    expected. When looking at the ingredients, organized convection
    looks most likely south of the Great Lakes within eastern portions
    of the Corn Belt Tuesday into Tuesday night and across the Upper
    Ohio Valley Wednesday into Wednesday night, where hourly rain
    amounts to 2.5" are possible. There is significant disagreement on Wednesday/Wednesday night on where a heavy rain axis would be
    across the eastern Corn Belt/Midwest, so for the time being, no
    Slight Risk has been drawn/assigned. Recent guidance nudged north,
    so the Slight Risk area on Tuesday was shifted similarly. For Wednesday/Wednesday night, a Slight Risk area was introduced for WV
    where the guidance has relatively good agreement on the potential
    for heavy rainfall within areas of significant relief.

    ..Southwest/Colorado...
    Broad Marginal Risk areas exist early to mid next week across
    portions of the Southwest, Rockies, and Great Basin. Ridging/warm
    700 hPa temperatures shifts north and weakens/lowers somewhat
    across the Intermountain West, which opens the door to broader
    convective development in the Southwest at some point, potentially
    next Wednesday, where above average precipitable water values
    persist over the next five days with minimal day to day variation.
    While there continues to be low confidence with the details,
    locally heavy rains with the potential of 2" an hour amounts could
    become more expansive Wednesday. A Slight Risk cannot be ruled out
    across portions of this area as we get closer to the days in
    question. As usual, urban areas, arroyos/dry washes, box/slot
    canyons, and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!80iTKzSTETZq50MPS6hK9tFbu55yJrr3hIig7clCSCnPVE1u92fAMsEYlu3iktSclxc9p_Qpm77JbQgG61ayt0RR9jc$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!80iTKzSTETZq50MPS6hK9tFbu55yJrr3hIig7clCSCnPVE1u92fAMsEYlu3iktSclxc9p_Qpm77JbQgG61aysmLRtQ0$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!80iTKzSTETZq50MPS6hK9tFbu55yJrr3hIig7clCSCnPVE1u92fAMsEYlu3iktSclxc9p_Qpm77JbQgG61ayHVgVZI0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 9 00:54:52 2026
    FOUS30 KWBC 090054
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    854 PM EDT Sat Aug 8 2026

    Day 1
    Valid 01Z Sun Aug 09 2026 - 12Z Sun Aug 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE OHIO VALLEY AND NORTHEAST, THE UPPER MIDWEST, AND THE
    SOUTHWEST...

    ...OH Valley to Northeast...
    One shortwave currently moving across NH and ME will continue to
    produce localized areas of heavy rainfall as it pushes east this
    evening. A cold front from OH into NY should also be a focus for
    isolated to scattered thunderstorms tonight. Enough forcing is
    present to sustain some development into the overnight hours, but
    generally quick cell motions and limited organization/coverage
    should keep any flash flood risk very isolated.

    ..SD into MN and IA...
    Still seeing a good signal for overnight upscale convective growth
    across portions of SD/MN. A strengthening low level jet and
    moisture convergence axis will combine with subtle mid level energy
    and an upper jet to the north to produce an expanding area of
    convection. Most signs point towards a forward propagating MCS,
    which should limit the extent of any flash flood risk. However,
    there is a strong enough axis of moisture transport and enough CAPE
    to support heavy rainfall rates. Thus a localized flash flood risk
    is possible both in the MCS formation phase where cell mergers are
    more likely (eastern SD), and also downstream over MN and IA if a
    leading band of convection ahead of the MCS results in local
    training. Overall not anticipating widespread flash flooding, but a
    few areas of impacts are possible overnight into Sunday morning.

    ...Southwest...
    Convection over portions of central AZ into southeast NV and
    southwest UT, and over the central Sierra, will continue to pose a
    localized flash flood risk for a few more hours. These areas
    should see decreasing convective coverage and intensity after 03z.

    Chenard


    Day 2
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    UPPER GREAT LAKES AND UPPER MISSISSIPPI VALLEY...

    ...Upper Great Lakes & Mississippi Valley...

    20Z Update: The overall pattern remains favorable for a multi-
    round convective episode during the D2 period with the area of
    greatest focus likely to materialize over northern IL and southern
    WI and points east with the Chicago area the most notable area of
    potential impacts. There's a growing concern for a more locally
    significant flash flood prospect for the Chicago metro, including
    adjacent suburbs with the nocturnal convective maturation that's
    expected on Sunday night into early Monday morning. Warm front
    positioning and a strengthening 850mb LLJ will be key components in
    the threat over the area, one that is more susceptible to flash
    flooding thanks to the broad urban sprawl that extends from
    southern Lake Michigan and encompasses the entire area spanning
    northeast IL through northwestern IN. 12z HREF neighborhood
    probabilities for >3" are upwards of 60-80% currently for the above
    region, including the center of Chicago proper where high run off
    capabilities are notorious for local flooding hazards. There are
    even some notable >5" probs of 40-60% within the area spanning the
    western and northern Chicago suburbs down through the center of
    Chicago proper, a testament to the potential in this setup, and a
    general agreement from the CAMs on the positioning of the heavier
    rainfall.

    Ensemble mean QPF is greater than 2" over much of the
    Chicago metro, a signal that typically favors at least scattered
    flash flooding with perhaps widespread flash flood concerns if
    everything comes together perfectly. The back-building scenario
    with the setup is the reason for such a strong mean QPF signature,
    correlating well with the strong low-level convergence regime and
    locally backed flow between sfc-700mb positioned near the warm
    front. Ultimately, that frontal positioning will be pivotal in
    where the heaviest rainfall will materialize, and current
    indications is it will be within that zone bisecting northern IL
    into northern IN by the second half of the period. In this case,
    there is enough of a signal and general consensus on a high-end
    SLGT risk forecast for that zone with emphasis on northeast IL and
    northwest IN given the elevated probabilities for >3" of rainfall.

    Kleebauer

    ..Previous Discussion..

    A series of disturbances moving eastward along the southern
    periphery of a large upper low well into Canada will result in
    multiple rounds of storms on Sunday across the Slight Risk area.
    The first will be the remnants of an MCS that will start the day in
    far southeastern Minnesota, and will then track south and east
    along the Wisconsin/Illinois border. The storms in general should
    be pretty fast moving, so it's unlikely too many flooding impacts
    will be seen from this feature alone. However, what it will do is
    prime the soils by moistening them up for the later round.

    The second round will form at the nose of a developing low level
    jet Sunday night. The storms will follow the greatest instability,
    which will mean the storms will track southward. The should be
    significantly slower moving, and much more widespread compared to
    the first round earlier in the day. The widely scattered instances
    of flash flooding associated with the Slight will be mostly
    confined to this Sunday night period. Urban and small stream
    impacts in and around Chicago and possibly Milwaukee are the most
    likely impacts.

    Wegman

    ...Marginals Elsewhere...

    20Z Update: Only minor adjustments made to the remaining MRGL risks
    across both the Eastern and Southwestern U.S. Primary change was a
    narrow expansion of the MRGL to include the VA Tidewater and
    southern VA as guidance insists on another round of convection with
    rates between 1-2"/hr impacting these areas by Sunday afternoon and
    early evening before dwindling with the loss of diurnal
    instability after sunset. Southwestern U.S. remains on track for
    prevalent monsoonal moisture making its presence known across AZ,
    extending northward through the Great Basin.

    Kleebauer

    ..Previous Discussion..

    As on previous days, deep tropical moisture across the Southeast
    will favor another round of afternoon showers and storms from
    northern Mississippi into the southern Appalachians. Flash flooding
    will likely be confined to areas where the storms are most
    persistent (northern Mississippi), or where terrain helps funnel
    the rainwater (southern Appalachians). Generally the storms, while
    scattered, should be disorganized, so a Marginal was maintained for
    now, though targeted Slights are certainly possible in the coming
    days.

    The monsoon will continue across the 4 Corners region on Sunday.
    While a bit more widespread over the Southwest, most organized
    convection will be very limited, so few changes to the inherited
    Marginal Risk were needed.

    Wegman


    Day 3
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE GREAT LAKES AND SOUTHEASTERN ARIZONA...

    ...Great Lakes...

    20Z Update: The setup for D3 remains pretty consistent in run-to-
    run continuity with the highlight of heavy rainfall extending over
    the southern Great Lakes and northern Ohio Valley into western PA
    and the adjacent WV Highlands. A lot of the setup is contingent on
    the behavior of any complexes that materialize upstream over the
    Midwest and migrate east through the forecast. Looks like activity
    will be prone to producing rates upwards of 2"/hr, locally higher
    given a robust moist and unstable airmass present on the northern
    periphery of a broad ridge to the south, and the southern
    inflection of a sprawling ULL over Canada. In any case, the setup
    is textbook for an area of above normal convective chances that
    will take advantage of both a favorable thermodynamic and kinematic
    environment as the positioning of the jet will favor large scale
    ascent across much of the Great Lakes and Ohio Valley into the
    Appalachian front. As of now, the only change from the previous
    forecast was to expand the SLGT a bit further south into WV and
    east to bank up against the western slopes of the Appalachians in
    PA. Will be monitoring this setup closely as a high-end SLGT is not
    out of the realm of possibility considering all of the above
    factors, as well as the addition of terrain influences on the
    eastern extent of the current SLGT.

    Kleebauer

    ..Previous Discussion..

    A large upper level low well over Canada will spin a strong
    shortwave across the Great Lakes on Monday. Deep tropical moisture
    will be drawn northward from the reservoir of moisture over the
    Southeast, allowing for widespread showers and thunderstorms,
    generally from Chicago east to portions of the Central
    Appalachians. The inherited Slight was expanded to the east, to
    includes much of eastern Ohio, western Pennsylvania, including
    Pittsburgh, and far western New York, including Buffalo with this
    update.

    Wegman

    ...Southeastern Arizona...

    20Z Update: A favorable setup for heavy rainfall across
    southeastern AZ exists within a majority of guidance with ensemble
    mean QPF pushing >1" over much of the terrain focused within
    eastern Pima, Santa Cruz, and Cochise counties along and south of
    I-10. The previous high-end SLGT forecast continues to have merit
    with some of the deterministic outputs pushing local totals up near
    3", a threshold that would undoubtedly cause locally significant
    flash flood concerns within the aforementioned areas. Areas like
    the Huachuca mountains over to I-19 are the most likely areas to
    see significant rainfall in the setup. As we move closer to CAMs
    range, it will be an area to monitor for potential further upgrades
    if the signal becomes more pronounced in the general magnitude of
    the rainfall forecast. For now, the SLGT remains with the
    highlighted area across the southern tier the noted high-end SLGT
    risk.

    Kleebauer

    ..Previous Discussion..

    Deep tropical moisture moving up the Gulf of California will
    intrude into southeastern Arizona on Monday, with PWATs exceeding
    1.5 inches in many areas. A thermal low due to the strong high
    aloft will support widespread shower and thunderstorm activity,
    particularly along the Mexican border and up I-19 from Nogales
    through Tucson. This corridor is both highly flood prone, has seen
    numerous days of widely scattered flash flooding in recent days,
    and is right in line for additional widespread convection Monday
    afternoon. There is considerable uncertainty moving west up I-10
    beyond Tucson, so the introduced Slight is primarily for this most
    vulnerable corridor, where a higher-end Slight in in place.

    Wegman


    Day 4 and Day 5

    Valid 12Z Tue Aug 11 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY...

    20z Update: Still on track for an excessive rainfall threat
    Tuesday from portions of IL/IN into WV. Some uncertainty on the
    exact latitude of the threat, and not seeing any strong trend in
    todays models. Thus only made a small southward expansion of the
    Slight risk to account for the consistent AIFS, which has been on
    the southern end of the model envelope. We were able to cut back
    on the Marginal risk over the Northeast. Only the GFS keeps
    robust convection across this region...with the
    ECMWF/ECENS/CMC/AIGFS all showing drier air over the northeast and
    the better convective threat farther southwest.

    On day 5 (Wednesday) a heavy rainfall threat will continue on the
    periphery of the southern U.S. ridge, with convection from the
    Southwest into the central/northern Plains, and then extending
    southeastward into portions of the OH and TN valley. The inherited
    Slight risk over WV was made a bit larger to include some of
    eastern KY and southern OH. Overall confidence in this area is low,
    as seeing divergence in model QPF solutions. Think there will be
    an excessive rainfall threat, but could easily see this Slight
    risk area shift in location and/or size over the coming days.
    Still seeing a model signal for organized convection over portions
    of SD/NE, but enough uncertainty on those details to keep a
    Marginal for now. The Southwest still look to be more active
    Wednesday, but spatial confidence too low to introduce any slight
    risk area at this time.

    Chenard

    ...Previous Discussion...

    ...Great Lakes/Northern and Central Plains/Midwest/Upper Ohio
    Valley...
    Early to mid next week, broad cyclonic flow expected to
    persist across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low
    moving from Hudson Bay across Quebec. A frontal boundary will lie
    along the southern periphery of this broad trough. Embedded
    shortwaves in this broad cyclonic flow will accentuate lift in the
    vicinity of this front where PW values are expected to rise to
    ~1.75" ahead of each set of shortwaves and low- level confluence is
    expected. When looking at the ingredients, organized convection
    looks most likely south of the Great Lakes within eastern portions
    of the Corn Belt Tuesday into Tuesday night and across the Upper
    Ohio Valley Wednesday into Wednesday night, where hourly rain
    amounts to 2.5" are possible. There is significant disagreement on Wednesday/Wednesday night on where a heavy rain axis would be
    across the eastern Corn Belt/Midwest, so for the time being, no
    Slight Risk has been drawn/assigned. Recent guidance nudged north,
    so the Slight Risk area on Tuesday was shifted similarly. For Wednesday/Wednesday night, a Slight Risk area was introduced for WV
    where the guidance has relatively good agreement on the potential
    for heavy rainfall within areas of significant relief.

    ..Southwest/Colorado...
    Broad Marginal Risk areas exist early to mid next week across
    portions of the Southwest, Rockies, and Great Basin. Ridging/warm
    700 hPa temperatures shifts north and weakens/lowers somewhat
    across the Intermountain West, which opens the door to broader
    convective development in the Southwest at some point, potentially
    next Wednesday, where above average precipitable water values
    persist over the next five days with minimal day to day variation.
    While there continues to be low confidence with the details,
    locally heavy rains with the potential of 2" an hour amounts could
    become more expansive Wednesday. A Slight Risk cannot be ruled out
    across portions of this area as we get closer to the days in
    question. As usual, urban areas, arroyos/dry washes, box/slot
    canyons, and burn scars would be most at risk for flash flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!992rIW2RTl2GG_UBQvGXnKxK9LrU4PLZxiXjmuOXvzAw0SL2y4xUmgYmTg8ZUjl8PEq6NdZZzdNA85j9N0ugk_RY6qM$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!992rIW2RTl2GG_UBQvGXnKxK9LrU4PLZxiXjmuOXvzAw0SL2y4xUmgYmTg8ZUjl8PEq6NdZZzdNA85j9N0ugbHB3Jrw$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!992rIW2RTl2GG_UBQvGXnKxK9LrU4PLZxiXjmuOXvzAw0SL2y4xUmgYmTg8ZUjl8PEq6NdZZzdNA85j9N0ugzTLrXTE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 9 08:06:08 2026
    FOUS30 KWBC 090805
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    405 AM EDT Sun Aug 9 2026

    Day 1
    Valid 12Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE UPPER MIDWEST...

    ...Upper Midwest...

    A series of thunderstorms currently ongoing from northern South
    Dakota and in parts of Minnesota this morning are expected to
    congeal into an MCS by late this morning, moving into the Slight
    risk area of Wisconsin around midday. This first bout will begin to
    prime the soils, but due to its fast eastward motion, is unlikely
    to cause too many flash flooding issues. The storms traverse the
    L.P. of Michigan late this afternoon and evening. Behind it, with
    southerly return flow still in place, the cold pool behind this MCS
    will act as a frontal boundary. The southerly flow will uplift
    moist and incredibly unstable air across the Chicagoland region. A
    renewed round of showers and thunderstorms is likely to form in
    that area as soon as this evening. Between the continued
    southwesterly flow of instability and moisture and the new cold
    pools from the storms, this second round of storms will have a
    struggle moving much of anywhere, unlike its predecessor. While it
    appears most likely this will occur near Chicago, which would be a
    big problem as far as flooding concerns go, there remains some
    uncertainty. Regardless, the storms continue to grow upscale and
    downwind, which in this case is towards the east. This will lead to
    additional training thunderstorms extending along the
    Michigan/Indiana border, potentially stretching into far
    northwestern Ohio. It's this overnight convection, which will
    likely persist to some extent right through the night that the
    Slight Risk is for.

    A higher end Slight is in place from Milwaukee and Chicago east
    along all of the Michigan/Indiana border to the corner of Ohio.
    Considering the aridity of the soils in this region for this first
    day of rain, it appears unlikely at this time that a Moderate Risk
    upgrade will be needed. However, prolonged heavy rainfall almost
    anywhere can overcome even the driest of soils, so such an upgrade
    can't be ruled out. Much of the shower and thunderstorm activity
    should be east of the Slight Risk area into Ohio and Ontario before
    sunrise on Monday morning.

    ...Southeast...

    Abundant deep tropical moisture will remain in place across much of
    the Southeast, as it has been for several days already, through the
    day today. Unlike further north, at these latitudes, a
    comprehensive forcing mechanism, especially from the upper levels
    will be lacking. Thus, with plentiful daytime heating, widespread
    disorganized convection is likely once again this afternoon over a
    large swath of country. The inherited Marginal was expanded down to
    the Gulf coast, as storms in the vicinity of New Orleans and
    Houston could cause localized and isolated flash flooding since any
    storms in this environment will be capable of short periods of
    multiple inch per hour rainfall rates given the abundance of
    moisture for the storms to work with. If flash flooding were to
    occur, it appears most likely in this region in the southern
    Appalachian region of far north Georgia and western North Carolina,
    where terrain effects could locally increase the duration of heavy
    rain from any storms that form.

    ...Southwest...

    Of the next 3 days, the monsoonal storms impacting the Southwest
    will be at a minimum today, generally focused on the larger terrain
    features such as the Mogollon Rim, and portions of Utah. The
    greatest moisture, as usual, will be closest to the Gulf of
    California in southwestern Arizona. So any storms that form along
    the Mexican border will likely have a higher chance of producing
    flash flooding compared to most other areas of the Southwest.
    Regardless, with a lack of real forcing, the storms should still be disorganized and therefore only produce isolated flash flooding in
    their localized areas today.

    Wegman


    Day 2
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS SOUTHERN ARIZONA...

    ...Midwest...

    The MCS that will be moving across Ohio at the start of the day is
    likely to persist as it traverses the state and moves into
    southwestern Pennsylvania and West Virginia. By Monday morning,
    the MCS should be fast enough moving that flash flooding resulting
    from it, especially during this most hostile period of the day for
    MCS sustenance. Nonetheless, the storms will prime the soils in PA
    and WV for later rounds of rain. During peak heating in the late
    afternoon, additional storms are likely to form in Indiana and
    Ohio, which will continue southeastward into West Virginia during
    the evening hours. Behind this complex of storms, the persistent
    LLJ advecting additional moisture and instability into the large
    collective cold pool will lay down a pseudo-cold front from
    northeastern Indiana into western and southern Ohio.

    The primary flooding threat will come Monday night as the LLJ
    running into the cold pool results in numerous additional storms
    forming along the slowly retreating cold pool boundary. The storms
    could reform as far back/west as Chicago, but appears most likely
    from northern Indiana and into western Ohio. The storms will track southeastward across those states, but due to the cold pool setup,
    the environment will be very favorable for training and
    backbuilding. Considering the rain in some areas of northern
    Illinois and northern Indiana could be hitting the same areas for
    the second consecutive day, a Moderate Risk upgrade can't be ruled
    out, as well as anywhere the storms could be most persistent into
    Ohio with a more short-range update.

    ...Southern Arizona...

    Monsoonal moisture will peak across southwestern Arizona on
    Monday. Storms are expected to initiate along the Mogollon Rim, and
    the numerous ranges of southeastern Arizona as normal during the
    afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona. As the storms track
    westward, they are expected to backbuild given the impressive
    amounts of moisture and instability they will run into as they move
    westward. Thus, the bigger cities such as Tucson and possibly
    Phoenix may see periods of showers and storms that will persist
    into the evening hours, since the ample moisture and instability in southwestern Arizona will sustain the storms past peak heating.
    The inherited Slight Risk is little changed, and the I-19 corridor
    from Nogales to Tucson remains the primary area that could be
    affected by the storms and their flash flooding.

    Wegman


    Day 3
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS FOR SOUTHERN ARIZONA...

    ...Midwest...

    A rinse-and-repeat pattern will unfold across the Midwest on
    Tuesday. Any morning MCSs from Monday night will continue towards
    the southeast into West Virginia from Ohio while the storms
    generally weaken Tuesday morning. Additional rounds of storms will
    likely follow in the form of fast moving lines, but still tracking
    over many of the same areas from prior days, from northern Indiana
    across much of Ohio, and weakening as they move into West Virginia
    late in the day. Just as on prior days, the storms will establish a
    cold pool/pseudo-front across Ohio that will act as a train track
    for additional storms to form along and track along by Tuesday
    night. That precise scenario will play out again Tuesday night, as
    storms form either immediately in the wake of any afternoon lines
    of storms or along their cold pool. Westerly flow of deep moisture
    will support the individual storms rather fast southeasterly motion
    from Indiana across Ohio and eventually into West Virginia.
    However, training and backbuilding will be common, and along a
    narrow corridor that could stretch from as far north as Pittsburgh
    south through the southern tip of West Virginia.

    It appears this training and repeating scenario will ramp up as
    compared to previous days on Tuesday, resulting in more common,
    stronger, and more persistent lines of storms developing and moving southeastward along the front. Given the likelihood that prior
    days' rains over these same areas will have saturated the soils by
    Day 3, and the general very flashy nature of the rivers of West
    Virginia, it appears a Moderate Risk upgrade will be probable in
    this region in the coming days.

    ...Southern Arizona...

    The strongest storms associated with the monsoon across southern
    Arizona on Tuesday are expected to form closer to the Mexican
    border as compared to prior days. Given the likelihood of flooding
    rains in this same area on Monday, despite the relative lack of
    rainfall expected on Tuesday as compared with Monday, a small
    Slight Risk upgrade for along the Mexican border was introduced
    with this update. Otherwise, expect a return to a "base state" as
    far as storm coverage, notably a significant decrease as compared
    to Monday, but similar to today/Sunday. This should allow some
    areas to dry out due to lack of activity on Tuesday.

    Wegman


    Day 4 and Day 5

    Valid 12Z Wed Aug 12 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    ...Portions of the Ohio Valley/Midwest/Corn Belt...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    and near Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~2" ahead of each set of
    shortwaves and low- level confluence is expected. When looking at
    the ingredients, organized convection looks most likely near
    portions of the Ohio Valley and the Corn Belt Wednesday into
    Thursday night, where the better 1000-500 hPa thickness difluence
    is forecast. Hourly rain amounts to 3" are possible. The Slight
    Risk on Wednesday/Wednesday night was broadened somewhat from
    continuity, with another Slight Risk introduced for
    Thursday/Thursday night near the IA/MO/IL state junction where
    guidance spread on the heavy rain signal is smaller than average.

    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday night. Broad Marginal
    Risk areas exist near and ahead of this upper level trough for portions
    of the Southwest, Intermountain West, and Northern/Central Plains.
    Increased upper level troughing opens the door to strengthening
    low-level level flow and broader convective development/coverage
    across the West and Plains as the mid-level cap further erodes.
    Above average precipitable water values slowly shift northward
    through the region, while AZ's return back towards seasonal
    averages Thursday night/early Friday. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. A Slight
    Risk was introduced for areas near the CO/WY/NE irregular border
    intersection where there was a fairly cohesive signal for heavy
    rainfall within a region of probable antiparallel flow between the
    low-level upslope flow and organized thunderstorm propagation
    moving against the low level wind. Urban areas, arroyos/dry washes,
    box/slot canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!5kcQVKZXRSrJu3V6n26ChIoKRA6QOVVaUy8OizpRY79myTL_APnfy08LcQz1Ca-FB7E7lWqQQkhP6ElMsmuNCnZ_yD0$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!5kcQVKZXRSrJu3V6n26ChIoKRA6QOVVaUy8OizpRY79myTL_APnfy08LcQz1Ca-FB7E7lWqQQkhP6ElMsmuNlrxCozg$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!5kcQVKZXRSrJu3V6n26ChIoKRA6QOVVaUy8OizpRY79myTL_APnfy08LcQz1Ca-FB7E7lWqQQkhP6ElMsmuNE8cff4s$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 9 15:49:24 2026
    FOUS30 KWBC 091548
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1148 AM EDT Sun Aug 9 2026

    Day 1
    Valid 16Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE UPPER MIDWEST...

    ...Upper Midwest...

    16Z Update: Initial wave of convection is currently pushing through
    IA/WI at this time with heavy rain focused over southern WI with a
    primary convective cluster leading to bouts of heavy rainfall
    between 1-2"/hr based on current obs. The forward propagation of
    the storms should limit the threat for flash flooding, but some
    isolated instances of flash flooding will plausible between Madison
    to Milwaukee with emphasis on the area between I-94 and I-41 (For
    more on this evolving setup, please see MPD #0984). This shortwave
    associated with the current convection will migrate east-southeast
    with a steady motion into the southern Great Lakes by the
    afternoon, kicking out of the area by the time the evening rolls
    around. Still some risk of thunderstorms across southern MI into
    the northern Ohio Valley with the disturbance, but flash flood
    threat will remain isolated overall.

    The coming evening is when the next round of thunderstorms will
    really cause issues as we see the approach of a warm front moving
    up from the south with the aid of a budding nocturnal LLJ and some
    backing flow centered over northern IL/IN up into southern WI and
    MI. The backed flow along with increasing surface convergence
    within the proximity of the warm front and any remnant cold pool(s)
    generated via the storms early in the period will provide the
    opportunity for a secondary pulse of convection in and around the
    area focused along and east of I-39/55 in IL over into northwestern
    IN and southwest MI after 00z. Hi-res suite continues to pin some
    significant rainfall totals between 2-4", locally higher near or
    within the Chicago metro and surround suburbs over into those areas
    downstream around the shores of Lake Michigan across IN/MI. 12z
    HREF neighborhood probabilities for >3" are actually a touch lower
    than the previous forecasts, but still a respectable 40-60%
    centered over the above area with the max positioned over
    southwestern MI.

    The urbanization factors along with rates between 1-2"/hr all
    within the expected environment will be sufficient for at least
    scattered flash flood instances with the highest prospects in those
    heavily urbanized areas within the Chicago metro to along the I-94
    corridor bordering the lake. The northern inflection of the threat
    seems to be near Holland, MI with the primary core just south.
    There is some prospects of the heavy rainfall axis focusing a bit
    further south with more emphasis on areas between I-80 and I-74 in
    IL into I-65 in IN. These outputs are generally more aggressive
    with the cold pool positioning being further south than the
    consensus leading to the convergence pattern displaced away from
    the southern portion of Lake Michigan. Something to monitor when
    assessing any potential deviations from the current forecast, but
    still a lower probability comparatively. As a result, maintained a
    broad SLGT risk across the Midwest into the southern portion of the
    Great Lakes and northern Ohio Valley with the axis of the risk
    genuinely encompassing the forecast positioning of the warm front
    by tonight into early tomorrow morning.

    Kleebauer

    ...Southeast...

    16Z Update: Changes were minor from the inherited MRGL risk across
    the Southeast and southern Mid Atlantic. The main area of concern
    will continue to be the Cumberland Plateau and points east through
    the southern Appalachians where slow cell motions and rainfall
    rates between 1-2"/hr could spur some localized flash flood impacts
    in the terrain over Tennessee into the Carolina mountains. Totals
    between 2-4" in the hardest hit areas seems to the consensus
    within the HREF prob fields indicating modest >3" probs between
    30-50% across southwest NC into the Smokey Mountains. Heavy rain
    prospects extend southwest into AL/MS/GA with local maxima >3"
    plausible in the mountains of north GA and over the Central Gulf
    coast in southern AL. Broad MRGL risk remains for all areas.

    Kleebauer

    ..Previous Discussion..

    Abundant deep tropical moisture will remain in place across much of
    the Southeast, as it has been for several days already, through the
    day today. Unlike further north, at these latitudes, a
    comprehensive forcing mechanism, especially from the upper levels
    will be lacking. Thus, with plentiful daytime heating, widespread
    disorganized convection is likely once again this afternoon over a
    large swath of country. The inherited Marginal was expanded down to
    the Gulf coast, as storms in the vicinity of New Orleans and
    Houston could cause localized and isolated flash flooding since any
    storms in this environment will be capable of short periods of
    multiple inch per hour rainfall rates given the abundance of
    moisture for the storms to work with. If flash flooding were to
    occur, it appears most likely in this region in the southern
    Appalachian region of far north Georgia and western North Carolina,
    where terrain effects could locally increase the duration of heavy
    rain from any storms that form.

    Wegman

    ...Southwest...

    16Z Update: No changes to the previous MRGL risk across the
    Southwestern CONUS as the forecast remains on track with solid
    run-to-run continuity on the expected thunderstorm coverage this
    afternoon into the early evening. One area of interest not within
    any risk is across the Peninsular Range in Southern California
    where thunderstorm genesis is anticipated after 18z today.
    Environment doesn't appear to be as robust as the coming days with
    more of a modest threat for locally heavy rainfall this afternoon.
    Considering the deterministic outputs running below what we would
    want to see for a more formidable flash flood setup, decided to
    maintain the nil in the area, but will make mention of a non-zero
    opportunity in that corridor of terrain for the period.

    Kleebauer

    ..Previous Discussion..

    Of the next 3 days, the monsoonal storms impacting the Southwest
    will be at a minimum today, generally focused on the larger terrain
    features such as the Mogollon Rim, and portions of Utah. The
    greatest moisture, as usual, will be closest to the Gulf of
    California in southwestern Arizona. So any storms that form along
    the Mexican border will likely have a higher chance of producing
    flash flooding compared to most other areas of the Southwest.
    Regardless, with a lack of real forcing, the storms should still be disorganized and therefore only produce isolated flash flooding in
    their localized areas today.

    Wegman


    Day 2
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS SOUTHERN ARIZONA...

    ...Midwest...

    The MCS that will be moving across Ohio at the start of the day is
    likely to persist as it traverses the state and moves into
    southwestern Pennsylvania and West Virginia. By Monday morning,
    the MCS should be fast enough moving that flash flooding resulting
    from it, especially during this most hostile period of the day for
    MCS sustenance. Nonetheless, the storms will prime the soils in PA
    and WV for later rounds of rain. During peak heating in the late
    afternoon, additional storms are likely to form in Indiana and
    Ohio, which will continue southeastward into West Virginia during
    the evening hours. Behind this complex of storms, the persistent
    LLJ advecting additional moisture and instability into the large
    collective cold pool will lay down a pseudo-cold front from
    northeastern Indiana into western and southern Ohio.

    The primary flooding threat will come Monday night as the LLJ
    running into the cold pool results in numerous additional storms
    forming along the slowly retreating cold pool boundary. The storms
    could reform as far back/west as Chicago, but appears most likely
    from northern Indiana and into western Ohio. The storms will track southeastward across those states, but due to the cold pool setup,
    the environment will be very favorable for training and
    backbuilding. Considering the rain in some areas of northern
    Illinois and northern Indiana could be hitting the same areas for
    the second consecutive day, a Moderate Risk upgrade can't be ruled
    out, as well as anywhere the storms could be most persistent into
    Ohio with a more short-range update.

    ...Southern Arizona...

    Monsoonal moisture will peak across southwestern Arizona on
    Monday. Storms are expected to initiate along the Mogollon Rim, and
    the numerous ranges of southeastern Arizona as normal during the
    afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona. As the storms track
    westward, they are expected to backbuild given the impressive
    amounts of moisture and instability they will run into as they move
    westward. Thus, the bigger cities such as Tucson and possibly
    Phoenix may see periods of showers and storms that will persist
    into the evening hours, since the ample moisture and instability in southwestern Arizona will sustain the storms past peak heating.
    The inherited Slight Risk is little changed, and the I-19 corridor
    from Nogales to Tucson remains the primary area that could be
    affected by the storms and their flash flooding.

    Wegman


    Day 3
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS FOR SOUTHERN ARIZONA...

    ...Midwest...

    A rinse-and-repeat pattern will unfold across the Midwest on
    Tuesday. Any morning MCSs from Monday night will continue towards
    the southeast into West Virginia from Ohio while the storms
    generally weaken Tuesday morning. Additional rounds of storms will
    likely follow in the form of fast moving lines, but still tracking
    over many of the same areas from prior days, from northern Indiana
    across much of Ohio, and weakening as they move into West Virginia
    late in the day. Just as on prior days, the storms will establish a
    cold pool/pseudo-front across Ohio that will act as a train track
    for additional storms to form along and track along by Tuesday
    night. That precise scenario will play out again Tuesday night, as
    storms form either immediately in the wake of any afternoon lines
    of storms or along their cold pool. Westerly flow of deep moisture
    will support the individual storms rather fast southeasterly motion
    from Indiana across Ohio and eventually into West Virginia.
    However, training and backbuilding will be common, and along a
    narrow corridor that could stretch from as far north as Pittsburgh
    south through the southern tip of West Virginia.

    It appears this training and repeating scenario will ramp up as
    compared to previous days on Tuesday, resulting in more common,
    stronger, and more persistent lines of storms developing and moving southeastward along the front. Given the likelihood that prior
    days' rains over these same areas will have saturated the soils by
    Day 3, and the general very flashy nature of the rivers of West
    Virginia, it appears a Moderate Risk upgrade will be probable in
    this region in the coming days.

    ...Southern Arizona...

    The strongest storms associated with the monsoon across southern
    Arizona on Tuesday are expected to form closer to the Mexican
    border as compared to prior days. Given the likelihood of flooding
    rains in this same area on Monday, despite the relative lack of
    rainfall expected on Tuesday as compared with Monday, a small
    Slight Risk upgrade for along the Mexican border was introduced
    with this update. Otherwise, expect a return to a "base state" as
    far as storm coverage, notably a significant decrease as compared
    to Monday, but similar to today/Sunday. This should allow some
    areas to dry out due to lack of activity on Tuesday.

    Wegman


    Day 4 and Day 5

    Valid 12Z Wed Aug 12 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    ...Portions of the Ohio Valley/Midwest/Corn Belt...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    and near Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~2" ahead of each set of
    shortwaves and low- level confluence is expected. When looking at
    the ingredients, organized convection looks most likely near
    portions of the Ohio Valley and the Corn Belt Wednesday into
    Thursday night, where the better 1000-500 hPa thickness difluence
    is forecast. Hourly rain amounts to 3" are possible. The Slight
    Risk on Wednesday/Wednesday night was broadened somewhat from
    continuity, with another Slight Risk introduced for
    Thursday/Thursday night near the IA/MO/IL state junction where
    guidance spread on the heavy rain signal is smaller than average.

    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday night. Broad Marginal
    Risk areas exist near and ahead of this upper level trough for portions
    of the Southwest, Intermountain West, and Northern/Central Plains.
    Increased upper level troughing opens the door to strengthening
    low-level level flow and broader convective development/coverage
    across the West and Plains as the mid-level cap further erodes.
    Above average precipitable water values slowly shift northward
    through the region, while AZ's return back towards seasonal
    averages Thursday night/early Friday. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. A Slight
    Risk was introduced for areas near the CO/WY/NE irregular border
    intersection where there was a fairly cohesive signal for heavy
    rainfall within a region of probable antiparallel flow between the
    low-level upslope flow and organized thunderstorm propagation
    moving against the low level wind. Urban areas, arroyos/dry washes,
    box/slot canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4XFBU_z4MUlJVCAUgQyiy1-yFly8sQeJULG2xKt3TAiHDCZei9n3PWdYOzDFSjFzvChgWvOxBNlIpas88crEr6A8J4c$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4XFBU_z4MUlJVCAUgQyiy1-yFly8sQeJULG2xKt3TAiHDCZei9n3PWdYOzDFSjFzvChgWvOxBNlIpas88crEuua5-Ek$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4XFBU_z4MUlJVCAUgQyiy1-yFly8sQeJULG2xKt3TAiHDCZei9n3PWdYOzDFSjFzvChgWvOxBNlIpas88crEX15MSYw$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Sun Aug 9 20:10:24 2026
    FOUS30 KWBC 092010
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    410 PM EDT Sun Aug 9 2026

    Day 1
    Valid 16Z Sun Aug 09 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE UPPER MIDWEST...

    ...Upper Midwest...

    16Z Update: Initial wave of convection is currently pushing through
    IA/WI at this time with heavy rain focused over southern WI with a
    primary convective cluster leading to bouts of heavy rainfall
    between 1-2"/hr based on current obs. The forward propagation of
    the storms should limit the threat for flash flooding, but some
    isolated instances of flash flooding will plausible between Madison
    to Milwaukee with emphasis on the area between I-94 and I-41 (For
    more on this evolving setup, please see MPD #0984). This shortwave
    associated with the current convection will migrate east-southeast
    with a steady motion into the southern Great Lakes by the
    afternoon, kicking out of the area by the time the evening rolls
    around. Still some risk of thunderstorms across southern MI into
    the northern Ohio Valley with the disturbance, but flash flood
    threat will remain isolated overall.

    The coming evening is when the next round of thunderstorms will
    really cause issues as we see the approach of a warm front moving
    up from the south with the aid of a budding nocturnal LLJ and some
    backing flow centered over northern IL/IN up into southern WI and
    MI. The backed flow along with increasing surface convergence
    within the proximity of the warm front and any remnant cold pool(s)
    generated via the storms early in the period will provide the
    opportunity for a secondary pulse of convection in and around the
    area focused along and east of I-39/55 in IL over into northwestern
    IN and southwest MI after 00z. Hi-res suite continues to pin some
    significant rainfall totals between 2-4", locally higher near or
    within the Chicago metro and surround suburbs over into those areas
    downstream around the shores of Lake Michigan across IN/MI. 12z
    HREF neighborhood probabilities for >3" are actually a touch lower
    than the previous forecasts, but still a respectable 40-60%
    centered over the above area with the max positioned over
    southwestern MI.

    The urbanization factors along with rates between 1-2"/hr all
    within the expected environment will be sufficient for at least
    scattered flash flood instances with the highest prospects in those
    heavily urbanized areas within the Chicago metro to along the I-94
    corridor bordering the lake. The northern inflection of the threat
    seems to be near Holland, MI with the primary core just south.
    There is some prospects of the heavy rainfall axis focusing a bit
    further south with more emphasis on areas between I-80 and I-74 in
    IL into I-65 in IN. These outputs are generally more aggressive
    with the cold pool positioning being further south than the
    consensus leading to the convergence pattern displaced away from
    the southern portion of Lake Michigan. Something to monitor when
    assessing any potential deviations from the current forecast, but
    still a lower probability comparatively. As a result, maintained a
    broad SLGT risk across the Midwest into the southern portion of the
    Great Lakes and northern Ohio Valley with the axis of the risk
    genuinely encompassing the forecast positioning of the warm front
    by tonight into early tomorrow morning.

    Kleebauer

    ...Southeast...

    16Z Update: Changes were minor from the inherited MRGL risk across
    the Southeast and southern Mid Atlantic. The main area of concern
    will continue to be the Cumberland Plateau and points east through
    the southern Appalachians where slow cell motions and rainfall
    rates between 1-2"/hr could spur some localized flash flood impacts
    in the terrain over Tennessee into the Carolina mountains. Totals
    between 2-4" in the hardest hit areas seems to the consensus
    within the HREF prob fields indicating modest >3" probs between
    30-50% across southwest NC into the Smokey Mountains. Heavy rain
    prospects extend southwest into AL/MS/GA with local maxima >3"
    plausible in the mountains of north GA and over the Central Gulf
    coast in southern AL. Broad MRGL risk remains for all areas.

    Kleebauer

    ..Previous Discussion..

    Abundant deep tropical moisture will remain in place across much of
    the Southeast, as it has been for several days already, through the
    day today. Unlike further north, at these latitudes, a
    comprehensive forcing mechanism, especially from the upper levels
    will be lacking. Thus, with plentiful daytime heating, widespread
    disorganized convection is likely once again this afternoon over a
    large swath of country. The inherited Marginal was expanded down to
    the Gulf coast, as storms in the vicinity of New Orleans and
    Houston could cause localized and isolated flash flooding since any
    storms in this environment will be capable of short periods of
    multiple inch per hour rainfall rates given the abundance of
    moisture for the storms to work with. If flash flooding were to
    occur, it appears most likely in this region in the southern
    Appalachian region of far north Georgia and western North Carolina,
    where terrain effects could locally increase the duration of heavy
    rain from any storms that form.

    Wegman

    ...Southwest...

    16Z Update: No changes to the previous MRGL risk across the
    Southwestern CONUS as the forecast remains on track with solid
    run-to-run continuity on the expected thunderstorm coverage this
    afternoon into the early evening. One area of interest not within
    any risk is across the Peninsular Range in Southern California
    where thunderstorm genesis is anticipated after 18z today.
    Environment doesn't appear to be as robust as the coming days with
    more of a modest threat for locally heavy rainfall this afternoon.
    Considering the deterministic outputs running below what we would
    want to see for a more formidable flash flood setup, decided to
    maintain the nil in the area, but will make mention of a non-zero
    opportunity in that corridor of terrain for the period.

    Kleebauer

    ..Previous Discussion..

    Of the next 3 days, the monsoonal storms impacting the Southwest
    will be at a minimum today, generally focused on the larger terrain
    features such as the Mogollon Rim, and portions of Utah. The
    greatest moisture, as usual, will be closest to the Gulf of
    California in southwestern Arizona. So any storms that form along
    the Mexican border will likely have a higher chance of producing
    flash flooding compared to most other areas of the Southwest.
    Regardless, with a lack of real forcing, the storms should still be disorganized and therefore only produce isolated flash flooding in
    their localized areas today.

    Wegman


    Day 2
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, AS WELL AS SOUTHERN ARIZONA...

    ...Midwest and Ohio Valley...

    20Z Update: The current synoptic pattern defined in the previous
    forecast remains valid as models are in agreement on a multi-round
    convective scenario with training potential increasing as we move
    into the evening hours Monday. Latest CAMs and associated HREF are
    keen on an axis of heavier convective impacts occurring over
    northern IN down through western OH with the highest probability
    for >3" (30-50%) located within the forecast theta_E gradient
    outlined via the cold pool remnants from the storms that will occur
    the first half of the period. The trends have favored a cell
    propagation from west-northwest to east-southeast as directed via
    the mean flow around the northern periphery of the ridge located
    over the Southern U.S. and the broad mid-level gyre spinning up
    over the eastern half of Canada. The combination of convergent
    flow within the boundary layer and the large scale ascent provided
    from the jet alignment over southern Ontario should enhance the
    overall precip component over the Ohio Valley leading to prolonged
    convective potential over the course of the overnight hours Monday
    into Tuesday.

    The likelihood of training/repeated round of thunderstorms in the
    vicinity of eastern IN and western OH has been increasing over the
    past series of runs from models leading to an enhanced prospect for
    flash flooding considering rates between 1-2"/hr are all but
    certain in the strongest cell cores. Despite antecedent dry soils
    leading into the period, there will still be bouts of scattered
    flash flooding, especially within those urbanized zones over the
    aforementioned areas extending from as far northwest Chicago and
    the I-65 corridor to as far east as I-75 and north of I-75. This
    area continues to be outlined within a high-end SLGT forecast with
    a non-zero opportunity for an upgrade in coming updates.

    Kleebauer

    ..Previous Discussion..

    The MCS that will be moving across Ohio at the start of the day is
    likely to persist as it traverses the state and moves into
    southwestern Pennsylvania and West Virginia. By Monday morning,
    the MCS should be fast enough moving that flash flooding resulting
    from it, especially during this most hostile period of the day for
    MCS sustenance. Nonetheless, the storms will prime the soils in PA
    and WV for later rounds of rain. During peak heating in the late
    afternoon, additional storms are likely to form in Indiana and
    Ohio, which will continue southeastward into West Virginia during
    the evening hours. Behind this complex of storms, the persistent
    LLJ advecting additional moisture and instability into the large
    collective cold pool will lay down a pseudo-cold front from
    northeastern Indiana into western and southern Ohio.

    The primary flooding threat will come Monday night as the LLJ
    running into the cold pool results in numerous additional storms
    forming along the slowly retreating cold pool boundary. The storms
    could reform as far back/west as Chicago, but appears most likely
    from northern Indiana and into western Ohio. The storms will track southeastward across those states, but due to the cold pool setup,
    the environment will be very favorable for training and
    backbuilding. Considering the rain in some areas of northern
    Illinois and northern Indiana could be hitting the same areas for
    the second consecutive day, a Moderate Risk upgrade can't be ruled
    out, as well as anywhere the storms could be most persistent into
    Ohio with a more short-range update.

    Wegman

    ...Southern Arizona...

    20Z Update: Models continue to indicate an increase in convective
    coverage and overall magnitude of thunderstorm activity across
    southern AZ as a stronger mid-level vorticity maxima, coupled with
    increasing PWATs initiates and maintains a stronger round of
    thunderstorms from western Cochise county into neighboring Santa
    Cruz and Pima counties as we move through Monday afternoon and
    evening. Heavy rain prospects extend well beyond this area, as
    well, much of AZ likely seeing scattered shower and thunderstorm
    coverage during the peak diurnal maxima. The area of greatest flash
    flood concern will continue to lie along and south of I-10 with the
    core of heavier rains likely situated within that area of I-19
    between Tuscon to Nogales. HREF probs for >1" are running between
    50-80% for that particular corridor with a secondary max located
    within the central and western Mogollon Rim. Modest probs exist for
    2" across southern AZ leading to a continued high-end SLGT risk
    over the above area and a broad MRGL expansion through the Desert
    Southwest up through the Great Basin.

    Kleebauer

    ..Previous Discussion..

    Monsoonal moisture will peak across southwestern Arizona on
    Monday. Storms are expected to initiate along the Mogollon Rim, and
    the numerous ranges of southeastern Arizona as normal during the
    afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona. As the storms track
    westward, they are expected to backbuild given the impressive
    amounts of moisture and instability they will run into as they move
    westward. Thus, the bigger cities such as Tucson and possibly
    Phoenix may see periods of showers and storms that will persist
    into the evening hours, since the ample moisture and instability in southwestern Arizona will sustain the storms past peak heating.
    The inherited Slight Risk is little changed, and the I-19 corridor
    from Nogales to Tucson remains the primary area that could be
    affected by the storms and their flash flooding.

    Wegman


    Day 3
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS FOR SOUTHERN ARIZONA...

    ...Midwest...

    20Z Update: Little change necessary from the previous forecast as
    consensus grows for a period of locally significant heavy rainfall
    over areas of IN/OH, extending into WV. This setup is favoring
    significant rainfall on a northwest to southeast alignment as a
    series of stronger mid-level disturbances migrate quickly through
    the flow with the height field oriented from the Northern Plains
    into the Central Appalachians. Both the ECENS and GEFS mean
    vorticity forecast show 3 distinct vorticity maxima migrating out
    of the Midwest into the Ohio Valley during the D3, bleeding into
    the D4 time frame. Multiple MCSs will likely transpire over the
    area extending from northwest IN down through OH into WV leading to
    some areas seeing multiple rounds of heavy rain and increasing
    flash flood prospects as each complex will prime the grounds as we
    move forward in time. Areas of interest for more significant
    impacts include those broad urban zones and the terrain influenced
    areas of WV and eastern OH as flash flood potential is generally
    higher due to higher run off capabilities and more enhanced
    riverine issues that couple with the heavy rainfall rates
    anticipated (1-2"/hr likely, locally higher). The previous high-end
    SLGT remains in effect, but there is a better than normal chance at
    an upgrade in future updates based on the proposed setup.

    Kleebauer

    ..Previous Discussion..

    A rinse-and-repeat pattern will unfold across the Midwest on
    Tuesday. Any morning MCSs from Monday night will continue towards
    the southeast into West Virginia from Ohio while the storms
    generally weaken Tuesday morning. Additional rounds of storms will
    likely follow in the form of fast moving lines, but still tracking
    over many of the same areas from prior days, from northern Indiana
    across much of Ohio, and weakening as they move into West Virginia
    late in the day. Just as on prior days, the storms will establish a
    cold pool/pseudo-front across Ohio that will act as a train track
    for additional storms to form along and track along by Tuesday
    night. That precise scenario will play out again Tuesday night, as
    storms form either immediately in the wake of any afternoon lines
    of storms or along their cold pool. Westerly flow of deep moisture
    will support the individual storms rather fast southeasterly motion
    from Indiana across Ohio and eventually into West Virginia.
    However, training and backbuilding will be common, and along a
    narrow corridor that could stretch from as far north as Pittsburgh
    south through the southern tip of West Virginia.

    It appears this training and repeating scenario will ramp up as
    compared to previous days on Tuesday, resulting in more common,
    stronger, and more persistent lines of storms developing and moving southeastward along the front. Given the likelihood that prior
    days' rains over these same areas will have saturated the soils by
    Day 3, and the general very flashy nature of the rivers of West
    Virginia, it appears a Moderate Risk upgrade will be probable in
    this region in the coming days.

    Wegman

    ...Southern Arizona...

    20Z Update: Little to no change necessary for the SLGT and MRGL
    risk placements across the Western U.S. for D3 as the general model
    consensus maintains a consistent output compared to the previous
    forecast.

    Kleebauer

    ..Previous Discussion..

    The strongest storms associated with the monsoon across southern
    Arizona on Tuesday are expected to form closer to the Mexican
    border as compared to prior days. Given the likelihood of flooding
    rains in this same area on Monday, despite the relative lack of
    rainfall expected on Tuesday as compared with Monday, a small
    Slight Risk upgrade for along the Mexican border was introduced
    with this update. Otherwise, expect a return to a "base state" as
    far as storm coverage, notably a significant decrease as compared
    to Monday, but similar to today/Sunday. This should allow some
    areas to dry out due to lack of activity on Tuesday.

    Wegman


    Day 4 and Day 5

    Valid 12Z Wed Aug 12 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    20z Update: More uncertainty with the OH valley Slight risk on day
    4 (Wednesday), with the GFS, AIGFS and AIFS showing a farther
    south convective axis by this time. Meanwhile the GEFS mean, ECMWF,
    UKMET and CMC remain solidly within the inherited Slight risk
    area. Opted to make little to no change to the Slight given this
    uncertainty, and will future shifts make adjustments if/when a
    clearer model trend becomes evident.

    Actually greater confidence in a heavy rainfall threat from IA/MO
    southeastward into IL/IN and KY on day 5 (Thursday). Looks like a
    favorable training convective setup on the periphery of the ridge,
    with anomalous 2"+ PWs pooling across this corridor. Models have
    been very consistent in highlighting a swath of heavy rainfall, so
    confidence is high in there being some flash flooding this day.
    Confidence is lower on the exact axis, with some run to run
    latitudinal differences noted. The issued Slight risk swath aligns
    with the current model consensus. This event seems to have some
    potential to evolve into a locally more significant flash flood
    threat across portions of this area.

    Chenard

    ...Previous Discussion...

    ...Portions of the Ohio Valley/Midwest/Corn Belt...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    and near Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~2" ahead of each set of
    shortwaves and low- level confluence is expected. When looking at
    the ingredients, organized convection looks most likely near
    portions of the Ohio Valley and the Corn Belt Wednesday into
    Thursday night, where the better 1000-500 hPa thickness difluence
    is forecast. Hourly rain amounts to 3" are possible. The Slight
    Risk on Wednesday/Wednesday night was broadened somewhat from
    continuity, with another Slight Risk introduced for
    Thursday/Thursday night near the IA/MO/IL state junction where
    guidance spread on the heavy rain signal is smaller than average.

    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday night. Broad Marginal
    Risk areas exist near and ahead of this upper level trough for portions
    of the Southwest, Intermountain West, and Northern/Central Plains.
    Increased upper level troughing opens the door to strengthening
    low-level level flow and broader convective development/coverage
    across the West and Plains as the mid-level cap further erodes.
    Above average precipitable water values slowly shift northward
    through the region, while AZ's return back towards seasonal
    averages Thursday night/early Friday. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. A Slight
    Risk was introduced for areas near the CO/WY/NE irregular border
    intersection where there was a fairly cohesive signal for heavy
    rainfall within a region of probable anti-parallel flow between
    the low-level upslope flow and organized thunderstorm propagation
    moving against the low level wind. Urban areas, arroyos/dry washes,
    box/slot canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4xJQ2THjhhaYYItkoTW7RapkEBdSN6B3iXmud66xZmHu9RELTFmzSFcHekKUwjhl2lntnJX9xc72NmFZTCOKE2_mPzc$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4xJQ2THjhhaYYItkoTW7RapkEBdSN6B3iXmud66xZmHu9RELTFmzSFcHekKUwjhl2lntnJX9xc72NmFZTCOKg3JEzLU$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4xJQ2THjhhaYYItkoTW7RapkEBdSN6B3iXmud66xZmHu9RELTFmzSFcHekKUwjhl2lntnJX9xc72NmFZTCOKOKq0OF0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 10 01:02:22 2026
    FOUS30 KWBC 100101
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    901 PM EDT Sun Aug 9 2026

    Day 1
    Valid 01Z Mon Aug 10 2026 - 12Z Mon Aug 10 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE UPPER MIDWEST...

    ...OH Valley to Great Lakes...
    A locally significant flash flash flood risk is still expected to
    evolve overnight across portions of IL, IN and possibly far
    southwest MI. An increasing 30-35kt southwesterly low level jet
    will result in a very strong corridor of moisture transport
    tonight. Convective development is likely at the nose of this axis
    where convergence is maximized. CAPE in excess of 3000 J/kg is
    expected to coincide with this convective area, with PWs
    increasing towards 2". Cloud layer mean flow is off the east, but
    wind profiles are conducive to backbuilding on the west-southwest
    flank of convection. Upwind corfidi vectors are off to the south at
    10-15kts, so we should see an eventual progression of convection
    in this direction. Nonetheless, we should see enough backbuilding
    to result in some flash flooding tonight.

    A bit of uncertainty on the exact axis of heaviest rainfall, and
    the axis should be rather narrow. Thus will maintain a higher end
    Slight risk for this area, with an axis of 2-4" of rain and
    scattered flash flooding likely. While not a guarantee, there is a
    potential for a narrow axis of rainfall upwards of 5-8" if this
    training scenario ends up maximized, which could result in locally
    significant flash flood impacts. Thus trends overnight will need to
    be closely monitored.

    ...Southeast...
    A lingering isolated flash flood threat from northern AL into NC
    should wind down as the evening progresses.

    ...NE and KS...
    Convection moving out of western NE may try to grow upscale into a
    convective cluster as it pushes southeast into central NE and
    northwest KS overnight. Definitely a strong enough instability
    pool to support this...and may see just enough of an uptick in
    easterly low level flow to support a growing convective cluster
    capable of producing localized flash flooding.

    ...AZ...
    Most of the western U.S. is seeing declining convective coverage
    and intensity. The exception is over central to southern AZ where
    convection propagating off to the southwest off the terrain may
    persist and result in an isolated flash flood risk.

    Chenard


    Day 2
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, AS WELL AS SOUTHERN ARIZONA...

    ...Midwest and Ohio Valley...

    20Z Update: The current synoptic pattern defined in the previous
    forecast remains valid as models are in agreement on a multi-round
    convective scenario with training potential increasing as we move
    into the evening hours Monday. Latest CAMs and associated HREF are
    keen on an axis of heavier convective impacts occurring over
    northern IN down through western OH with the highest probability
    for >3" (30-50%) located within the forecast theta_E gradient
    outlined via the cold pool remnants from the storms that will occur
    the first half of the period. The trends have favored a cell
    propagation from west-northwest to east-southeast as directed via
    the mean flow around the northern periphery of the ridge located
    over the Southern U.S. and the broad mid-level gyre spinning up
    over the eastern half of Canada. The combination of convergent
    flow within the boundary layer and the large scale ascent provided
    from the jet alignment over southern Ontario should enhance the
    overall precip component over the Ohio Valley leading to prolonged
    convective potential over the course of the overnight hours Monday
    into Tuesday.

    The likelihood of training/repeated round of thunderstorms in the
    vicinity of eastern IN and western OH has been increasing over the
    past series of runs from models leading to an enhanced prospect for
    flash flooding considering rates between 1-2"/hr are all but
    certain in the strongest cell cores. Despite antecedent dry soils
    leading into the period, there will still be bouts of scattered
    flash flooding, especially within those urbanized zones over the
    aforementioned areas extending from as far northwest Chicago and
    the I-65 corridor to as far east as I-75 and north of I-75. This
    area continues to be outlined within a high-end SLGT forecast with
    a non-zero opportunity for an upgrade in coming updates.

    Kleebauer

    ..Previous Discussion..

    The MCS that will be moving across Ohio at the start of the day is
    likely to persist as it traverses the state and moves into
    southwestern Pennsylvania and West Virginia. By Monday morning,
    the MCS should be fast enough moving that flash flooding resulting
    from it, especially during this most hostile period of the day for
    MCS sustenance. Nonetheless, the storms will prime the soils in PA
    and WV for later rounds of rain. During peak heating in the late
    afternoon, additional storms are likely to form in Indiana and
    Ohio, which will continue southeastward into West Virginia during
    the evening hours. Behind this complex of storms, the persistent
    LLJ advecting additional moisture and instability into the large
    collective cold pool will lay down a pseudo-cold front from
    northeastern Indiana into western and southern Ohio.

    The primary flooding threat will come Monday night as the LLJ
    running into the cold pool results in numerous additional storms
    forming along the slowly retreating cold pool boundary. The storms
    could reform as far back/west as Chicago, but appears most likely
    from northern Indiana and into western Ohio. The storms will track southeastward across those states, but due to the cold pool setup,
    the environment will be very favorable for training and
    backbuilding. Considering the rain in some areas of northern
    Illinois and northern Indiana could be hitting the same areas for
    the second consecutive day, a Moderate Risk upgrade can't be ruled
    out, as well as anywhere the storms could be most persistent into
    Ohio with a more short-range update.

    Wegman

    ...Southern Arizona...

    20Z Update: Models continue to indicate an increase in convective
    coverage and overall magnitude of thunderstorm activity across
    southern AZ as a stronger mid-level vorticity maxima, coupled with
    increasing PWATs initiates and maintains a stronger round of
    thunderstorms from western Cochise county into neighboring Santa
    Cruz and Pima counties as we move through Monday afternoon and
    evening. Heavy rain prospects extend well beyond this area, as
    well, much of AZ likely seeing scattered shower and thunderstorm
    coverage during the peak diurnal maxima. The area of greatest flash
    flood concern will continue to lie along and south of I-10 with the
    core of heavier rains likely situated within that area of I-19
    between Tuscon to Nogales. HREF probs for >1" are running between
    50-80% for that particular corridor with a secondary max located
    within the central and western Mogollon Rim. Modest probs exist for
    2" across southern AZ leading to a continued high-end SLGT risk
    over the above area and a broad MRGL expansion through the Desert
    Southwest up through the Great Basin.

    Kleebauer

    ..Previous Discussion..

    Monsoonal moisture will peak across southwestern Arizona on
    Monday. Storms are expected to initiate along the Mogollon Rim, and
    the numerous ranges of southeastern Arizona as normal during the
    afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona. As the storms track
    westward, they are expected to backbuild given the impressive
    amounts of moisture and instability they will run into as they move
    westward. Thus, the bigger cities such as Tucson and possibly
    Phoenix may see periods of showers and storms that will persist
    into the evening hours, since the ample moisture and instability in southwestern Arizona will sustain the storms past peak heating.
    The inherited Slight Risk is little changed, and the I-19 corridor
    from Nogales to Tucson remains the primary area that could be
    affected by the storms and their flash flooding.

    Wegman


    Day 3
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST AS WELL AS FOR SOUTHERN ARIZONA...

    ...Midwest...

    20Z Update: Little change necessary from the previous forecast as
    consensus grows for a period of locally significant heavy rainfall
    over areas of IN/OH, extending into WV. This setup is favoring
    significant rainfall on a northwest to southeast alignment as a
    series of stronger mid-level disturbances migrate quickly through
    the flow with the height field oriented from the Northern Plains
    into the Central Appalachians. Both the ECENS and GEFS mean
    vorticity forecast show 3 distinct vorticity maxima migrating out
    of the Midwest into the Ohio Valley during the D3, bleeding into
    the D4 time frame. Multiple MCSs will likely transpire over the
    area extending from northwest IN down through OH into WV leading to
    some areas seeing multiple rounds of heavy rain and increasing
    flash flood prospects as each complex will prime the grounds as we
    move forward in time. Areas of interest for more significant
    impacts include those broad urban zones and the terrain influenced
    areas of WV and eastern OH as flash flood potential is generally
    higher due to higher run off capabilities and more enhanced
    riverine issues that couple with the heavy rainfall rates
    anticipated (1-2"/hr likely, locally higher). The previous high-end
    SLGT remains in effect, but there is a better than normal chance at
    an upgrade in future updates based on the proposed setup.

    Kleebauer

    ..Previous Discussion..

    A rinse-and-repeat pattern will unfold across the Midwest on
    Tuesday. Any morning MCSs from Monday night will continue towards
    the southeast into West Virginia from Ohio while the storms
    generally weaken Tuesday morning. Additional rounds of storms will
    likely follow in the form of fast moving lines, but still tracking
    over many of the same areas from prior days, from northern Indiana
    across much of Ohio, and weakening as they move into West Virginia
    late in the day. Just as on prior days, the storms will establish a
    cold pool/pseudo-front across Ohio that will act as a train track
    for additional storms to form along and track along by Tuesday
    night. That precise scenario will play out again Tuesday night, as
    storms form either immediately in the wake of any afternoon lines
    of storms or along their cold pool. Westerly flow of deep moisture
    will support the individual storms rather fast southeasterly motion
    from Indiana across Ohio and eventually into West Virginia.
    However, training and backbuilding will be common, and along a
    narrow corridor that could stretch from as far north as Pittsburgh
    south through the southern tip of West Virginia.

    It appears this training and repeating scenario will ramp up as
    compared to previous days on Tuesday, resulting in more common,
    stronger, and more persistent lines of storms developing and moving southeastward along the front. Given the likelihood that prior
    days' rains over these same areas will have saturated the soils by
    Day 3, and the general very flashy nature of the rivers of West
    Virginia, it appears a Moderate Risk upgrade will be probable in
    this region in the coming days.

    Wegman

    ...Southern Arizona...

    20Z Update: Little to no change necessary for the SLGT and MRGL
    risk placements across the Western U.S. for D3 as the general model
    consensus maintains a consistent output compared to the previous
    forecast.

    Kleebauer

    ..Previous Discussion..

    The strongest storms associated with the monsoon across southern
    Arizona on Tuesday are expected to form closer to the Mexican
    border as compared to prior days. Given the likelihood of flooding
    rains in this same area on Monday, despite the relative lack of
    rainfall expected on Tuesday as compared with Monday, a small
    Slight Risk upgrade for along the Mexican border was introduced
    with this update. Otherwise, expect a return to a "base state" as
    far as storm coverage, notably a significant decrease as compared
    to Monday, but similar to today/Sunday. This should allow some
    areas to dry out due to lack of activity on Tuesday.

    Wegman


    Day 4 and Day 5

    Valid 12Z Wed Aug 12 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    20z Update: More uncertainty with the OH valley Slight risk on day
    4 (Wednesday), with the GFS, AIGFS and AIFS showing a farther
    south convective axis by this time. Meanwhile the GEFS mean, ECMWF,
    UKMET and CMC remain solidly within the inherited Slight risk
    area. Opted to make little to no change to the Slight given this
    uncertainty, and will future shifts make adjustments if/when a
    clearer model trend becomes evident.

    Actually greater confidence in a heavy rainfall threat from IA/MO
    southeastward into IL/IN and KY on day 5 (Thursday). Looks like a
    favorable training convective setup on the periphery of the ridge,
    with anomalous 2"+ PWs pooling across this corridor. Models have
    been very consistent in highlighting a swath of heavy rainfall, so
    confidence is high in there being some flash flooding this day.
    Confidence is lower on the exact axis, with some run to run
    latitudinal differences noted. The issued Slight risk swath aligns
    with the current model consensus. This event seems to have some
    potential to evolve into a locally more significant flash flood
    threat across portions of this area.

    Chenard

    ...Previous Discussion...

    ...Portions of the Ohio Valley/Midwest/Corn Belt...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low in
    and near Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough. Embedded shortwaves in this broad
    cyclonic flow will accentuate lift in the vicinity of this front
    where PW values are expected to rise to ~2" ahead of each set of
    shortwaves and low- level confluence is expected. When looking at
    the ingredients, organized convection looks most likely near
    portions of the Ohio Valley and the Corn Belt Wednesday into
    Thursday night, where the better 1000-500 hPa thickness difluence
    is forecast. Hourly rain amounts to 3" are possible. The Slight
    Risk on Wednesday/Wednesday night was broadened somewhat from
    continuity, with another Slight Risk introduced for
    Thursday/Thursday night near the IA/MO/IL state junction where
    guidance spread on the heavy rain signal is smaller than average.

    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday night. Broad Marginal
    Risk areas exist near and ahead of this upper level trough for portions
    of the Southwest, Intermountain West, and Northern/Central Plains.
    Increased upper level troughing opens the door to strengthening
    low-level level flow and broader convective development/coverage
    across the West and Plains as the mid-level cap further erodes.
    Above average precipitable water values slowly shift northward
    through the region, while AZ's return back towards seasonal
    averages Thursday night/early Friday. While there continues to be
    low confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. A Slight
    Risk was introduced for areas near the CO/WY/NE irregular border
    intersection where there was a fairly cohesive signal for heavy
    rainfall within a region of probable antiparallel flow between the
    low-level upslope flow and organized thunderstorm propagation
    moving against the low level wind. Urban areas, arroyos/dry washes,
    box/slot canyons, and burn scars would be most at risk for flash
    flooding.

    Roth


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!761-nv3JtmXziJjlG4odAHy2ih0422brznVzVD3Qe67KhzX2v3qoN3D9ywcHlW1VRoMoshoU4T3uGQXZgXZNdEr4lIU$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!761-nv3JtmXziJjlG4odAHy2ih0422brznVzVD3Qe67KhzX2v3qoN3D9ywcHlW1VRoMoshoU4T3uGQXZgXZNYclRTm8$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!761-nv3JtmXziJjlG4odAHy2ih0422brznVzVD3Qe67KhzX2v3qoN3D9ywcHlW1VRoMoshoU4T3uGQXZgXZNYO4Kz1M$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 10 06:54:02 2026
    FOUS30 KWBC 100653
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    253 AM EDT Mon Aug 10 2026

    Day 1
    Valid 12Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, & SOUTHERN ARIZONA...


    ...Midwest and Ohio Valley...
    A deep layer cyclone across Hudson Bay rules the roost, keeping
    the equatorward edge of the Westerlies from the Northern Plains
    into portions of the Ohio Valley. This is near where a front and/or
    resultant outflow boundaries from convection will align and where
    an instability gradient is most likely to set up. Confluent low-
    level westerly flow is forecast near this boundary. Two to three
    rounds of convection are expected within an area of difluent
    1000-500 hPa thickness, implying organized convection. The
    ingredients available support hourly rain amounts to 3" where cells
    merge/train or where mesocyclones form. While the guidance is
    showing an emergent signal for heavy rain across portions of SD and
    IA, it is neither high enough nor agreeable enough for a Slight
    Risk but do believe the threat is on the higher end of a Marginal
    Risk. Farther to the east across portions of the Midwest/eastern
    Corn Belt south of the Great Lakes into the Upper Ohio Valley,
    a broad swath of rainfall is anticipated. Flash flood guidance is
    modest to low here, so even though the mesoscale signal for 3"+ in
    24 hours was modest and spotty, so saw no issues with the high end
    Slight Risk inherited from continuity. Local totals to 6" are
    possible on an isolated basis.


    ...Southeast...
    Disorganized convection with brief, locally high rain rates are
    expected during daytime heating. The more concentrated area of
    heavy rainfall lies along portions of the Middle and Upper TX
    Coasts during Monday morning as onshore flow brings a slug of 2"+
    precipitable water values and instability off the Gulf of Mexico.
    The Marginal Risk from continuity appears to cover the situation
    sufficiently.


    ...Southern Arizona...
    Monsoonal moisture increases across southern Arizona on Monday.
    Storms are expected to initiate along the Mogollon Rim, and the
    numerous ranges of southeastern Arizona and terrain in NM during
    the afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona and could lead to
    some level of organization. Hourly rain amounts to 2" are possible
    where cells sit, train, or backbuild. The inherited Slight Risk is
    little changed -- southeast AZ is forecast to see the longest
    period of heavy rainfall.

    Roth


    Day 2
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE A MODERATE RISK OF EXCESSIVE RAINFALL IN AND NEAR
    PORTIONS OF OHIO AND WEST VIRGINIA...


    ...Midwest...
    The general flow pattern is similar to Monday. The equatorward
    edge of the Westerlies is forecast to lie from the Northern Plains
    into portions of the Ohio Valley where there is also low-level
    confluence, difluent 1000-500 hPa thickness, and an instability
    gradient to focus organized convection. This led to similar risk
    area placement. Hourly rain amounts to 3" and local totals to 6"
    remain possible given the available ingredients. There is a decent
    likelihood that prior days' rains over these same areas will have
    saturated the soils further by Tuesday, and when combined with the
    general very flashy nature of the rivers/terrain of West Virginia
    and coordination with RLX/the Charleston WV forecast office, a
    Moderate Risk area was introduced for portions of southern OH and
    western WV.


    ...Southern Arizona...
    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases from
    Monday to Tuesday as an upper level trough settles in to the CA
    Coast and ridging near the Four Corners weakens, which should lead
    to less mid-level capping and broader convective coverage.

    Roth


    Day 3
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE OHIO VALLEY, MIDWEST, & ARIZONA...


    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...
    Broad cyclonic flow expected to persist across the northern tier
    of the Lower 48 from the Northern Plains/Upper MS Valley, eastward
    through the Midwest/Great Lakes and into the Northeast, to the
    south of a closed mid-level low that has shifted into Quebec. A
    frontal boundary will lie along the southern periphery of this
    broad trough from portions of the Northern and Central Plains into
    portions of the Ohio Valley and Appalachians. Embedded shortwaves
    in this broad cyclonic flow will accentuate lift in the vicinity of
    this front where PW values are expected to rise to ~2" ahead of
    each set of shortwaves and low- level confluence is expected.

    The guidance is showing a growing signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly
    rain amounts to 3" and local totals to 6" remain possible. A high
    end Slight Risk lies across portions of the region due to previous
    days of rains further saturating soils. There is a bit of spread of
    the heavy rain signal seen in the guidance, with the 00z UKMET/old
    12z ECMWF the lowest and the 00z Canadian Regional/RDPM the
    highest. Due to the uncertainty in the heavy rain signal, held off
    on a Moderate Risk for the time being.


    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and Plains when compared to previous days as the mid-level cap
    further erodes. Above average precipitable water values slowly
    shift northward through the region. While there continues to be low
    confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. Urban
    areas, arroyos/dry washes, box/slot canyons, and burn scars would
    be most at risk for flash flooding. A Slight Risk was introduced
    across southeast AZ.

    Roth


    Day 4 and Day 5
    Valid 12Z Thu Aug 13 2026 - 12Z Sat Aug 15 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FROM THE MID-
    MISSOURI VALLEY THROUGH THE OHIO VALLEY, PORTIONS OF THE HIGH
    PLAINS, AND SOUTHEASTERN ARIZONA TO WESTERN NEW MEXICO ON
    THURSDAY...

    Out west, the monsoon will have one final day where moisture across
    Arizona and New Mexico will be well above normal. Flattening upper
    level troughing that lifts northeastward away from Arizona and
    southern New Mexico should allow the showers and storms that form
    in that region to reduce the total atmospheric moisture quite a
    bit, with no replenishment overnight Thursday night. The Slight
    risk in this region follows where numerous prior days heavy rains
    impacted portions of southeastern Arizona and western New Mexico.
    Low FFGs still support widely scattered instances of flash flooding
    due to highly favorable hydrology (hydrophobic soils) in the flood
    prone areas.

    A large Slight Risk was introduced for much of the Front Ranges and
    High Plains from the Sangre de Cristos of northern New Mexico north
    through southeastern Montana. The aforementioned lifting upper
    level trough will have the opposite effect as further south, namely
    greatly increasing convective coverage and intensity in this
    generally flood prone region. A potent upper level shortwave riding northeastward along the eastern periphery of the positively tilted
    longwave trough will locally greatly increase convective coverage
    across the Plains of Colorado in particular. With a potent easterly
    low level jet advecting deep tropical moisture that has been in
    place across the eastern half of the country westward, the storms
    will run into an increasingly moisture rich and unstable
    environment. This will support backbuilding and training storms as
    the fuel for the storms is continually replenished. Further
    upgrades to the risk outlook are possible in the coming days,
    especially should urban areas such as Denver remain in the forecast
    for multiple inches of rain Thursday afternoon and evening.

    Finally, the Slight across portions of the Midwest and lower Ohio
    Valley was expanded east through much of West Virginia. With
    continued rain for a third consecutive day expected into West
    Virginia, despite somewhat lower total expected rainfall, the flood
    prone nature of the terrain there supports a higher risk for
    flooding. Downstream along the Ohio River, they will also be
    enduring the latest of a multi-day rainfall event on Thursday, also
    suggesting that FFGs by Thursday will be much lower across much of
    the Ohio Valley and supporting the Slight Risk upgrade. A plume of
    deep tropical moisture will bank itself along a stationary front
    suck just south of the southern ends of Lakes Michigan and Erie.
    This will support backbuilding and training of convection from Iowa
    straight through to West Virginia in the form of numerous rounds of
    storms that each follow a similar track, resulting in repeating
    storms. Some areas in this zone too may require risk upgrades as
    the event draws closer and moves into CAMS range.

    By Day 5/Friday, the signals for heavy rain become much more
    diffuse and spread out, with a few areas still highlighted,
    including northeastern Colorado, much of Iowa, and southern West
    Virginia. All 3 of these areas may have been hit hard with heavy
    rains on Day 4/Thursday, but since it's highly likely there will be
    large changes in both the placement and intensity of the heavy rain
    signals in each of these areas, have opted to keep all 3 in a
    Marginal risk for now, albeit a higher end one. Slight Risks will
    definitely be considered should these signals remain in future
    forecasts.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4_HigtFD0GfhGVZkDKH7nr3EaVYwQelNGAvCby28ASEV-dRjNxW_KUH5mU0VBoRT_dqLahE1s3Gl8uTxPaVvlexL9ew$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4_HigtFD0GfhGVZkDKH7nr3EaVYwQelNGAvCby28ASEV-dRjNxW_KUH5mU0VBoRT_dqLahE1s3Gl8uTxPaVvX1Uh-Fg$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4_HigtFD0GfhGVZkDKH7nr3EaVYwQelNGAvCby28ASEV-dRjNxW_KUH5mU0VBoRT_dqLahE1s3Gl8uTxPaVvOZRc1GU$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 10 15:57:14 2026
    FOUS30 KWBC 101556
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1156 AM EDT Mon Aug 10 2026

    Day 1
    Valid 16Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, & SOUTHERN ARIZONA...

    ...Midwest and Ohio Valley...

    16Z Update: Only minor changes necessary to the SLGT risk
    positioned over the central Midwest near Chicago, across the Ohio
    River Valley with the greatest threat likely over Central Ohio into
    West Virginia. 12z CAMs indicate a pretty solid threat for >3"
    for areas between I-80 to US50 in OH as the HREF neighborhood probs
    come in between 40-60% for the 3 inch threshold within the
    aforementioned zone. The Columbus area is the most notable urban
    center in the middle of the higher prob fields, however, the more
    complex terrain and drainage areas of eastern OH into WV will be
    noteworthy for more localized significant flash flood prospects
    beginning this evening, carrying through the overnight hours.
    Environmental conditions are ripe for heavy rainfall rates between
    2-3"/hr in the strongest cells with intra-hour rates likely to push
    upwards of 4-5"/hr in a few cells. This is in part to a very
    buoyant environment and modest shear located across the region
    allowing for maturing mesocyclone initiation and maintenance to
    occur during the peak of the convective regime. Already seeing some
    alignment in this mornings convection across OH orient more
    northwest to southeast in part to the cold pool fanning from the
    storms themselves as the the upwind shear vectors align within the
    general mean flow on the southern periphery of the upper low
    situated over Canada. This will be a theme for the period, and in
    the coming days for this general convective forward motion and
    potential for repeating as the prevailing steering pattern will see
    very little deviation in what is evolving currently. A high-end
    SLGT is forecast over much of OH and the western half of WV with
    the western extent back into eastern IN.

    Expect another round of convection to form across northern IL later
    this afternoon with guidance initiating convection after 19z across
    areas north of I-80. The Chicago suburbs and potentially the city
    of Chicago will see another round of heavy rainfall that will add
    to an already saturated environment in and around the metro area
    thanks to last nights convective impacts. This round of heavier
    precip does look to be a bit south of the previous episode, so that
    could offset the worst case of overlap, however the environment is
    more than capable for rates between 1-2"/hr during the time frame
    of impact, so scattered flash flood prospects fall within the
    general SLGT risk threshold, leading to only a minor adjustment of
    the SLGT to encompass the I-94 stretch between Milwaukee and
    Chicago to account for some guidance promoting the potential
    overlap of those harder hit areas yesterday/last night.

    Upstream over the Dakotas, the first in several shortwaves will
    eject out of the Front Range into the Northern Plains around the
    northern periphery of the ridge situated across the Southern U.S.
    Convective initiation will occur this evening as the nocturnal LLJ
    promotes deeper layer shear and a greater advection of moisture
    within the lower boundary layer. Addition of the large scale
    forcing and maturing low-level environment will help ignite the
    next round of thunderstorm activity across SD with the highest
    potential for heavy rainfall likely to occur east of the Missouri
    River into the I-29 corridor on the eastern side of SD. FFG's in
    the areas are higher than areas further east which should limit a
    more substantial flash flood scenario, however rates will likely be
    prolific enough to engage in isolated to widely scattered flash
    flood prospects, especially as you move closer to the interstate
    over the eastern side of the state. A MRGL risk remains in place,
    however the risk is likely on the higher side and bordering the
    necessity for a higher risk, so will have to monitor closely.

    Kleebauer

    ..Previous Discussion..

    A deep layer cyclone across Hudson Bay rules the roost, keeping
    the equatorward edge of the Westerlies from the Northern Plains
    into portions of the Ohio Valley. This is near where a front and/or
    resultant outflow boundaries from convection will align and where
    an instability gradient is most likely to set up. Confluent low-
    level westerly flow is forecast near this boundary. Two to three
    rounds of convection are expected within an area of diffluent
    1000-500 hPa thickness, implying organized convection. The
    ingredients available support hourly rain amounts to 3" where cells
    merge/train or where mesocyclones form. While the guidance is
    showing an emergent signal for heavy rain across portions of SD and
    IA, it is neither high enough nor agreeable enough for a Slight
    Risk but do believe the threat is on the higher end of a Marginal
    Risk. Farther to the east across portions of the Midwest/eastern
    Corn Belt south of the Great Lakes into the Upper Ohio Valley,
    a broad swath of rainfall is anticipated. Flash flood guidance is
    modest to low here, so even though the mesoscale signal for 3"+ in
    24 hours was modest and spotty, so saw no issues with the high end
    Slight Risk inherited from continuity. Local totals to 6" are
    possible on an isolated basis.

    Roth

    ...Southeast...

    16Z Update: Little change necessary from the previous issuance as
    the forecast remains on track. Most notable change was the removal
    of the MRGL risk across eastern FL as the greatest potential looks
    to lie across the western half of the state with the most prominent
    threat across the western coast in urban corridor between Tampa to
    Fort Meyers along the sea breeze. Modest probs for >3" exist in
    that zone, as well as over the interior Southeast and the TX coast,
    but thankfully high FFG's should preclude a greater threat. Urban
    centers will be the most at risk for flash flooding considering the
    antecedent environment with the soils.

    Kleebauer

    ..Previous Discussion..

    Disorganized convection with brief, locally high rain rates are
    expected during daytime heating. The more concentrated area of
    heavy rainfall lies along portions of the Middle and Upper TX
    Coasts during Monday morning as onshore flow brings a slug of 2"+
    precipitable water values and instability off the Gulf of Mexico.
    The Marginal Risk from continuity appears to cover the situation
    sufficiently.

    Roth

    ...Southern Arizona...

    16Z Update: No changes to the previous forecast as the current
    setup remains favorable for an elevated flash flood threat over
    southern AZ with the highlight remaining the I-19 corridor and
    adjacent desert over southeastern Pima county. HREF probs for >1"
    continue to reside within the 60-90% range with >2" probs more
    modest (25-45%), but still noteworthy for that particular area of
    the CONUS. A high-end SLGT is forecast over the above area for the
    threat.

    Kleebauer

    ..Previous Discussion..

    Monsoonal moisture increases across southern Arizona on Monday.
    Storms are expected to initiate along the Mogollon Rim, and the
    numerous ranges of southeastern Arizona and terrain in NM during
    the afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona and could lead to
    some level of organization. Hourly rain amounts to 2" are possible
    where cells sit, train, or backbuild. The inherited Slight Risk is
    little changed -- southeast AZ is forecast to see the longest
    period of heavy rainfall.

    Roth


    Day 2
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE A MODERATE RISK OF EXCESSIVE RAINFALL IN AND NEAR
    PORTIONS OF OHIO AND WEST VIRGINIA...

    ...Midwest...
    The general flow pattern is similar to Monday. The equatorward
    edge of the Westerlies is forecast to lie from the Northern Plains
    into portions of the Ohio Valley where there is also low-level
    confluence, difluent 1000-500 hPa thickness, and an instability
    gradient to focus organized convection. This led to similar risk
    area placement. Hourly rain amounts to 3" and local totals to 6"
    remain possible given the available ingredients. There is a decent
    likelihood that prior days' rains over these same areas will have
    saturated the soils further by Tuesday, and when combined with the
    general very flashy nature of the rivers/terrain of West Virginia
    and coordination with RLX/the Charleston WV forecast office, a
    Moderate Risk area was introduced for portions of southern OH and
    western WV.

    ...Southern Arizona...
    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases from
    Monday to Tuesday as an upper level trough settles in to the CA
    Coast and ridging near the Four Corners weakens, which should lead
    to less mid-level capping and broader convective coverage.

    Roth


    Day 3
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...
    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low that
    has shifted into Quebec. A frontal boundary will lie along the
    southern periphery of this broad trough from portions of the
    Northern and Central Plains into portions of the Ohio Valley and
    Appalachians. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front where PW values are
    expected to rise to ~2" ahead of each set of shortwaves and low-
    level confluence is expected.

    The guidance is showing a growing signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly
    rain amounts to 3" and local totals to 6" remain possible. A high
    end Slight Risk lies across portions of the region due to previous
    days of rains further saturating soils. There is a bit of spread of
    the heavy rain signal seen in the guidance, with the 00z UKMET/old
    12z ECMWF the lowest and the 00z Canadian Regional/RDPM the
    highest. Due to the uncertainty in the heavy rain signal, held off
    on a Moderate Risk for the time being.

    ..The West/Central & Northern Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and Plains when compared to previous days as the mid-level cap
    further erodes. Above average precipitable water values slowly
    shift northward through the region. While there continues to be low
    confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. Urban
    areas, arroyos/dry washes, box/slot canyons, and burn scars would
    be most at risk for flash flooding. A Slight Risk was introduced
    across southeast AZ.

    Roth


    Day 4 and Day 5
    Valid 12Z Thu Aug 13 2026 - 12Z Sat Aug 15 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FROM THE MID-
    MISSOURI VALLEY THROUGH THE OHIO VALLEY, PORTIONS OF THE HIGH
    PLAINS, AND SOUTHEASTERN ARIZONA TO WESTERN NEW MEXICO ON
    THURSDAY...

    Out west, the monsoon will have one final day where moisture across
    Arizona and New Mexico will be well above normal. Flattening upper
    level troughing that lifts northeastward away from Arizona and
    southern New Mexico should allow the showers and storms that form
    in that region to reduce the total atmospheric moisture quite a
    bit, with no replenishment overnight Thursday night. The Slight
    risk in this region follows where numerous prior days heavy rains
    impacted portions of southeastern Arizona and western New Mexico.
    Low FFGs still support widely scattered instances of flash flooding
    due to highly favorable hydrology (hydrophobic soils) in the flood
    prone areas.

    A large Slight Risk was introduced for much of the Front Ranges and
    High Plains from the Sangre de Cristos of northern New Mexico north
    through southeastern Montana. The aforementioned lifting upper
    level trough will have the opposite effect as further south, namely
    greatly increasing convective coverage and intensity in this
    generally flood prone region. A potent upper level shortwave riding northeastward along the eastern periphery of the positively tilted
    longwave trough will locally greatly increase convective coverage
    across the Plains of Colorado in particular. With a potent easterly
    low level jet advecting deep tropical moisture that has been in
    place across the eastern half of the country westward, the storms
    will run into an increasingly moisture rich and unstable
    environment. This will support backbuilding and training storms as
    the fuel for the storms is continually replenished. Further
    upgrades to the risk outlook are possible in the coming days,
    especially should urban areas such as Denver remain in the forecast
    for multiple inches of rain Thursday afternoon and evening.

    Finally, the Slight across portions of the Midwest and lower Ohio
    Valley was expanded east through much of West Virginia. With
    continued rain for a third consecutive day expected into West
    Virginia, despite somewhat lower total expected rainfall, the flood
    prone nature of the terrain there supports a higher risk for
    flooding. Downstream along the Ohio River, they will also be
    enduring the latest of a multi-day rainfall event on Thursday, also
    suggesting that FFGs by Thursday will be much lower across much of
    the Ohio Valley and supporting the Slight Risk upgrade. A plume of
    deep tropical moisture will bank itself along a stationary front
    suck just south of the southern ends of Lakes Michigan and Erie.
    This will support backbuilding and training of convection from Iowa
    straight through to West Virginia in the form of numerous rounds of
    storms that each follow a similar track, resulting in repeating
    storms. Some areas in this zone too may require risk upgrades as
    the event draws closer and moves into CAMS range.

    By Day 5/Friday, the signals for heavy rain become much more
    diffuse and spread out, with a few areas still highlighted,
    including northeastern Colorado, much of Iowa, and southern West
    Virginia. All 3 of these areas may have been hit hard with heavy
    rains on Day 4/Thursday, but since it's highly likely there will be
    large changes in both the placement and intensity of the heavy rain
    signals in each of these areas, have opted to keep all 3 in a
    Marginal risk for now, albeit a higher end one. Slight Risks will
    definitely be considered should these signals remain in future
    forecasts.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!5B_oZ454jcut9QJCrC9H8zmJUrXC19MHYIeCMmz9bXRAMlHIEypGv1Q8AkflnCcNnzINtljvyQ3165X9TWjJLfD0UaY$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!5B_oZ454jcut9QJCrC9H8zmJUrXC19MHYIeCMmz9bXRAMlHIEypGv1Q8AkflnCcNnzINtljvyQ3165X9TWjJuZweVVM$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!5B_oZ454jcut9QJCrC9H8zmJUrXC19MHYIeCMmz9bXRAMlHIEypGv1Q8AkflnCcNnzINtljvyQ3165X9TWjJrc2qIkM$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Mon Aug 10 19:38:16 2026
    FOUS30 KWBC 101937
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    337 PM EDT Mon Aug 10 2026

    Day 1
    Valid 16Z Mon Aug 10 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, & SOUTHERN ARIZONA...

    ...Midwest and Ohio Valley...

    16Z Update: Only minor changes necessary to the SLGT risk
    positioned over the central Midwest near Chicago, across the Ohio
    River Valley with the greatest threat likely over Central Ohio into
    West Virginia. 12z CAMs indicate a pretty solid threat for >3"
    for areas between I-80 to US50 in OH as the HREF neighborhood probs
    come in between 40-60% for the 3 inch threshold within the
    aforementioned zone. The Columbus area is the most notable urban
    center in the middle of the higher prob fields, however, the more
    complex terrain and drainage areas of eastern OH into WV will be
    noteworthy for more localized significant flash flood prospects
    beginning this evening, carrying through the overnight hours.
    Environmental conditions are ripe for heavy rainfall rates between
    2-3"/hr in the strongest cells with intra-hour rates likely to push
    upwards of 4-5"/hr in a few cells. This is in part to a very
    buoyant environment and modest shear located across the region
    allowing for maturing mesocyclone initiation and maintenance to
    occur during the peak of the convective regime. Already seeing some
    alignment in this mornings convection across OH orient more
    northwest to southeast in part to the cold pool fanning from the
    storms themselves as the the upwind shear vectors align within the
    general mean flow on the southern periphery of the upper low
    situated over Canada. This will be a theme for the period, and in
    the coming days for this general convective forward motion and
    potential for repeating as the prevailing steering pattern will see
    very little deviation in what is evolving currently. A high-end
    SLGT is forecast over much of OH and the western half of WV with
    the western extent back into eastern IN.

    Expect another round of convection to form across northern IL later
    this afternoon with guidance initiating convection after 19z across
    areas north of I-80. The Chicago suburbs and potentially the city
    of Chicago will see another round of heavy rainfall that will add
    to an already saturated environment in and around the metro area
    thanks to last nights convective impacts. This round of heavier
    precip does look to be a bit south of the previous episode, so that
    could offset the worst case of overlap, however the environment is
    more than capable for rates between 1-2"/hr during the time frame
    of impact, so scattered flash flood prospects fall within the
    general SLGT risk threshold, leading to only a minor adjustment of
    the SLGT to encompass the I-94 stretch between Milwaukee and
    Chicago to account for some guidance promoting the potential
    overlap of those harder hit areas yesterday/last night.

    Upstream over the Dakotas, the first in several shortwaves will
    eject out of the Front Range into the Northern Plains around the
    northern periphery of the ridge situated across the Southern U.S.
    Convective initiation will occur this evening as the nocturnal LLJ
    promotes deeper layer shear and a greater advection of moisture
    within the lower boundary layer. Addition of the large scale
    forcing and maturing low-level environment will help ignite the
    next round of thunderstorm activity across SD with the highest
    potential for heavy rainfall likely to occur east of the Missouri
    River into the I-29 corridor on the eastern side of SD. FFG's in
    the areas are higher than areas further east which should limit a
    more substantial flash flood scenario, however rates will likely be
    prolific enough to engage in isolated to widely scattered flash
    flood prospects, especially as you move closer to the interstate
    over the eastern side of the state. A MRGL risk remains in place,
    however the risk is likely on the higher side and bordering the
    necessity for a higher risk, so will have to monitor closely.

    Kleebauer

    ..Previous Discussion..

    A deep layer cyclone across Hudson Bay rules the roost, keeping
    the equatorward edge of the Westerlies from the Northern Plains
    into portions of the Ohio Valley. This is near where a front and/or
    resultant outflow boundaries from convection will align and where
    an instability gradient is most likely to set up. Confluent low-
    level westerly flow is forecast near this boundary. Two to three
    rounds of convection are expected within an area of diffluent
    1000-500 hPa thickness, implying organized convection. The
    ingredients available support hourly rain amounts to 3" where cells
    merge/train or where mesocyclones form. While the guidance is
    showing an emergent signal for heavy rain across portions of SD and
    IA, it is neither high enough nor agreeable enough for a Slight
    Risk but do believe the threat is on the higher end of a Marginal
    Risk. Farther to the east across portions of the Midwest/eastern
    Corn Belt south of the Great Lakes into the Upper Ohio Valley,
    a broad swath of rainfall is anticipated. Flash flood guidance is
    modest to low here, so even though the mesoscale signal for 3"+ in
    24 hours was modest and spotty, so saw no issues with the high end
    Slight Risk inherited from continuity. Local totals to 6" are
    possible on an isolated basis.

    Roth

    ...Southeast...

    16Z Update: Little change necessary from the previous issuance as
    the forecast remains on track. Most notable change was the removal
    of the MRGL risk across eastern FL as the greatest potential looks
    to lie across the western half of the state with the most prominent
    threat across the western coast in urban corridor between Tampa to
    Fort Meyers along the sea breeze. Modest probs for >3" exist in
    that zone, as well as over the interior Southeast and the TX coast,
    but thankfully high FFG's should preclude a greater threat. Urban
    centers will be the most at risk for flash flooding considering the
    antecedent environment with the soils.

    Kleebauer

    ..Previous Discussion..

    Disorganized convection with brief, locally high rain rates are
    expected during daytime heating. The more concentrated area of
    heavy rainfall lies along portions of the Middle and Upper TX
    Coasts during Monday morning as onshore flow brings a slug of 2"+
    precipitable water values and instability off the Gulf of Mexico.
    The Marginal Risk from continuity appears to cover the situation
    sufficiently.

    Roth

    ...Southern Arizona...

    16Z Update: No changes to the previous forecast as the current
    setup remains favorable for an elevated flash flood threat over
    southern AZ with the highlight remaining the I-19 corridor and
    adjacent desert over southeastern Pima county. HREF probs for >1"
    continue to reside within the 60-90% range with >2" probs more
    modest (25-45%), but still noteworthy for that particular area of
    the CONUS. A high-end SLGT is forecast over the above area for the
    threat.

    Kleebauer

    ..Previous Discussion..

    Monsoonal moisture increases across southern Arizona on Monday.
    Storms are expected to initiate along the Mogollon Rim, and the
    numerous ranges of southeastern Arizona and terrain in NM during
    the afternoon hours. Unlike prior days, enough easterly flow,
    especially in the upper levels, will successfully push those
    showers and storms off the mountains and towards the lower
    elevations and valleys of southwestern Arizona and could lead to
    some level of organization. Hourly rain amounts to 2" are possible
    where cells sit, train, or backbuild. The inherited Slight Risk is
    little changed -- southeast AZ is forecast to see the longest
    period of heavy rainfall.

    Roth


    Day 2
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO VALLEY...

    ...Midwest and Ohio Valley...

    20Z Update: Continued active setup across the Midwest to Ohio
    Valley will lead to widespread heavy rainfall from multiple
    convective complexes that will also exhibit potential for training
    and back-building over areas of IN/OH during the period. A growing
    consensus within both the CAMs and global deterministic allowed for
    a higher confidence forecast across much of southern Ohio back into
    eastern Indiana to connect with the already forecast MDT risk over
    portions of West Virginia. Latest HREF blended mean QPF depicted a
    long axis of 2-4" totals between areas just east of Indianapolis
    all the way towards Charleston, WV with some of the local maxima
    actually closer to 6-8" when assessing individual deterministic.
    This setup is conducive for these totals with a classic summer
    convective scenario of multiple MCS propagating through a
    persistent northwest to southeast aligned mean flow thanks to a
    squeeze player between the northern periphery of a broad ridge
    across the Southern U.S. and a deep cyclonic gyre spinning up over
    east-central Canada. The combined effort between the two distinct
    upper features will create a mid to upper level "highway" for
    several shortwave impulses to migrate out of the High Plains and
    traverse the central Midwest into the Ohio Valley. The coupling of
    favored jet dynamics and increased large scale forcing from the
    prevalent mid-level vorticity maxima will interact with a suitable thermodynamic environment positioned over the Ohio and Tennessee
    Valley's as noted via some prolific theta_E advection occurring
    during Tuesday afternoon.

    Area PWAT anomalies on the order of 1-2 standard deviations above
    normal will be present across much of the Ohio Valley back into the
    central and southern Midwest providing a sufficient deep, moist
    profile that will be conducive for efficient rainfall processes
    necessary for more formidable heavy rain accumulations.
    Increasingly backed flow in the lower boundary layer will occur
    over portions of IN/OH thanks to the disturbance advecting into the
    area by later Tuesday leading to a period of training and/or back-
    building convection after initiation, carrying through at least the
    first half of the evening hours. Remnant cold pool from today's
    convection will be a focal point for the training potential and the
    recent CAMs have been locking in on the area extending from eastern
    IN into southwestern WV as the most likely orientation and location
    of the surface feature in question. This correlated to some
    significant rainfall forecasts from the 12z CAMs suite within that
    zone leading to enhanced neighborhood probabilities for both the
    3" (50-80%) and >5" (30-50%) thresholds during the period. 24hr
    10yr-ARI exceedance probs across the same areas are fairly robust
    with a bullseye of 40-60% located between Muncie, IN to Wilmington,
    OH with the same area already seeing 20-35% probs for even the
    100yr-ARI exceedance threshold, a testament to the anticipated
    magnitude of heavy rainfall for the coming setup.

    In coordination with the OHRFC and local WFO's from IN/OH/WV, the
    previous MDT risk was expanded across portions of eastern Indiana,
    the southern-third of Ohio, into western side of WV, mainly along
    and west of the I-79 corridor. Significant flash flooding is likely
    in these areas with widespread flash flood warnings and rapid
    riverine responses likely to cause issues lingering through the
    rest of the week as the overall setup extends beyond the D2 period.

    Kleebauer

    ...Southern Arizona...

    20Z Update: Latest CAMs and associated HREF continue to pin another
    round of heavy rainfall across the southern and southeastern
    portion of AZ thanks to elevated PWATs between 2-3 deviations above
    normal and a very buoyant environment conducive for heavy rainfall
    development. Prob fields for >1" remain very high (70-90%) over the
    area extending from Cochise county over into the eastern half of
    Pima, extending north towards the I-10 corridor in Tuscon. I-19
    remains the focal point for heavier rainfall, however the ridge
    positioning would invite more of southeast AZ into the picture for
    locally heavy rains, including the Huachuca Mountains that will
    likely be another focus for development as we move into Tuesday
    afternoon. The previous SLGT risk forecast was maintained as the
    signal remains consistent with little run-to-run variability.

    Kleebauer

    ..Previous Discussion..

    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases from
    Monday to Tuesday as an upper level trough settles in to the CA
    Coast and ridging near the Four Corners weakens, which should lead
    to less mid-level capping and broader convective coverage.

    Roth


    Day 3
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...

    20Z Update: The previous SLGT risk with high-end SLGT risk
    potential remains across portions of the Ohio Valley as the signal
    for heavy rainfall continues over the region, despite continued
    inconsistencies within the global deterministic. The setup on
    exactly where the heaviest rainfall will focus is still on the
    tricky side as the location of the remnant cold pool from
    Tuesday/Wednesday AM convection will be a focal point for where the
    next round of convection will transpire. There is a growing
    likelihood that the area extending from northern KY through
    southern OH will be the primary area of interest when you couple
    with the expected heavy rains the prior periods leading to priming,
    or even already flooded areas before the next round occurs. The
    global deterministic is all over the place with where the heavier
    rains will occur, but one consistency is the areal expanse of heavy
    convection is broader than the previous periods leading to a much
    larger SLGT risk situated from the Midwest through much of the Ohio
    Valley.

    The prospects for a risk upgrade where any overlap of heavy
    rainfall is high, so the expectation is for an addition of a higher
    risk probable at this point in time. That said, we need a bit more
    consensus from ensembles and deterministic, alike to prompt an
    upgrade over a particular area. The most notable area for a
    consideration to an upgrade is likely the southwestern quadrant of
    WV into southeast OH where complex terrain and funneling within
    the valleys west of I-79 and within the bounds of I-64 have the
    greatest potential just based off the National Blend and modest
    probs for >1" and >2" thresholds. For now, felt it was prudent to
    provide another round or two of model runs before inserting any
    upgrades, but will make mention that the opportunity in the future
    is higher than normal for continued significant flash flooding and
    an expected upgrade.

    Kleebauer

    ..Previous Discussion..

    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low that
    has shifted into Quebec. A frontal boundary will lie along the
    southern periphery of this broad trough from portions of the
    Northern and Central Plains into portions of the Ohio Valley and
    Appalachians. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front where PW values are
    expected to rise to ~2" ahead of each set of shortwaves and low-
    level confluence is expected.

    The guidance is showing a growing signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly
    rain amounts to 3" and local totals to 6" remain possible. A high
    end Slight Risk lies across portions of the region due to previous
    days of rains further saturating soils. There is a bit of spread of
    the heavy rain signal seen in the guidance, with the 00z UKMET/00z
    ECMWF the lowest and the 00z Canadian Regional/RDPS the highest.
    Due to the uncertainty in the heavy rain signal, held off on a
    Moderate Risk for the time being.

    Roth

    ..The West/Central & Northern Plains...

    20Z Update: The previous SLGT risk forecast was generally unchanged
    from the overnight issuance as models remains steadfast in their
    presentation of heavy rainfall situated across southeastern AZ.
    This area will have seen multiple days of heavy rains leading into
    the period, so the prospects for scattered flash flood concerns are
    elevated relative to normal. Totals of 1-2", locally higher are
    forecast across the area with multiple areas across the Interior
    West and the Northern Plains also likely to see similar precip
    outputs thanks to a favorable setup across the western half of the
    CONUS. FFG's are much higher outside the southern deserts, so the
    threat for more significant impacts are lower, so a broad MRGL
    exists elsewhere to account for the threat.

    Kleebauer

    ..Previous Discussion..

    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and Plains when compared to previous days as the mid-level cap
    further erodes. Above average precipitable water values slowly
    shift northward through the region. While there continues to be low
    confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. Urban
    areas, arroyos/dry washes, box/slot canyons, and burn scars would
    be most at risk for flash flooding. A Slight Risk was introduced
    across southeast AZ.

    Roth


    Day 4 and Day 5

    Valid 12Z Thu Aug 13 2026 - 12Z Sat Aug 15 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FROM THE MID-
    MISSOURI VALLEY THROUGH THE OHIO VALLEY, PORTIONS OF THE HIGH
    PLAINS, AND SOUTHEASTERN ARIZONA TO WESTERN NEW MEXICO ON
    THURSDAY...

    20Z Update...
    The 12Z guidance did not present any reason to make significant
    changes to the previous outlook. Therefore, made only minor
    adjustments.

    Pereira

    Previous Discussion...
    Out west, the monsoon will have one final
    day where moisture across Arizona and New Mexico will be well above
    normal. Flattening upper level troughing that lifts northeastward
    away from Arizona and southern New Mexico should allow the showers
    and storms that form in that region to reduce the total atmospheric
    moisture quite a bit, with no replenishment overnight Thursday
    night. The Slight risk in this region follows where numerous prior
    days heavy rains impacted portions of southeastern Arizona and
    western New Mexico. Low FFGs still support widely scattered
    instances of flash flooding due to highly favorable hydrology
    (hydrophobic soils) in the flood prone areas.

    A large Slight Risk was introduced for much of the Front Ranges and
    High Plains from the Sangre de Cristos of northern New Mexico north
    through southeastern Montana. The aforementioned lifting upper
    level trough will have the opposite effect as further south, namely
    greatly increasing convective coverage and intensity in this
    generally flood prone region. A potent upper level shortwave riding northeastward along the eastern periphery of the positively tilted
    longwave trough will locally greatly increase convective coverage
    across the Plains of Colorado in particular. With a potent easterly
    low level jet advecting deep tropical moisture that has been in
    place across the eastern half of the country westward, the storms
    will run into an increasingly moisture rich and unstable
    environment. This will support backbuilding and training storms as
    the fuel for the storms is continually replenished. Further
    upgrades to the risk outlook are possible in the coming days,
    especially should urban areas such as Denver remain in the forecast
    for multiple inches of rain Thursday afternoon and evening.

    Finally, the Slight across portions of the Midwest and lower Ohio
    Valley was expanded east through much of West Virginia. With
    continued rain for a third consecutive day expected into West
    Virginia, despite somewhat lower total expected rainfall, the flood
    prone nature of the terrain there supports a higher risk for
    flooding. Downstream along the Ohio River, they will also be
    enduring the latest of a multi-day rainfall event on Thursday, also
    suggesting that FFGs by Thursday will be much lower across much of
    the Ohio Valley and supporting the Slight Risk upgrade. A plume of
    deep tropical moisture will bank itself along a stationary front
    suck just south of the southern ends of Lakes Michigan and Erie.
    This will support backbuilding and training of convection from Iowa
    straight through to West Virginia in the form of numerous rounds of
    storms that each follow a similar track, resulting in repeating
    storms. Some areas in this zone too may require risk upgrades as
    the event draws closer and moves into CAMS range.

    By Day 5/Friday, the signals for heavy rain become much more
    diffuse and spread out, with a few areas still highlighted,
    including northeastern Colorado, much of Iowa, and southern West
    Virginia. All 3 of these areas may have been hit hard with heavy
    rains on Day 4/Thursday, but since it's highly likely there will be
    large changes in both the placement and intensity of the heavy rain
    signals in each of these areas, have opted to keep all 3 in a
    Marginal risk for now, albeit a higher end one. Slight Risks will
    definitely be considered should these signals remain in future
    forecasts.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!5xvYH6gt9M8Xw1u-SjzbQGIBCTSD4Ak9SEhd8YKqfqTVfbMjbLvhpdHL9-fqk1sC1noT2OyxY7OhC3yh1LwtfkfGUro$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!5xvYH6gt9M8Xw1u-SjzbQGIBCTSD4Ak9SEhd8YKqfqTVfbMjbLvhpdHL9-fqk1sC1noT2OyxY7OhC3yh1LwtOirIzFA$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!5xvYH6gt9M8Xw1u-SjzbQGIBCTSD4Ak9SEhd8YKqfqTVfbMjbLvhpdHL9-fqk1sC1noT2OyxY7OhC3yh1LwteR9U8g0$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 11 01:04:56 2026
    FOUS30 KWBC 110104
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    904 PM EDT Mon Aug 10 2026

    Day 1
    Valid 01Z Tue Aug 11 2026 - 12Z Tue Aug 11 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    MIDWEST, OHIO VALLEY, & SOUTHERN ARIZONA...

    01Z Update...

    Hi-res models performed poorly through the day across the Midwest-Ohio
    Valley, indicating convection would break out much earlier than
    what has occurred. However, convection has finally started
    organize, sparked by a mid-level shortwave moving from northern
    Illinois into Indiana that is interacting with a moist (PWs 1.75-2
    in) and very unstable airmass (MUCAPEs 4000-5000 J/kg). This should
    continue to support storm development through the evening, with
    the coverage of storms producing 2+ in/hr rates increasing. While
    much of the 12-18Z guidance has verified poorly, the more recent of
    runs of the HRRR/RRFS appear to have a better handle on the
    current conditions and therefore, along with radar/satellite
    trends, were the basis for much of the updates for the central to
    eastern U.S. While some of the totals advertised by the daytime
    guidance may be well-overdone and/or spatially misplaced, still
    feel the Slight Risk centered over the Ohio Valley is warranted.
    Heavy rates, along with areas of training are expected to support a
    swath of heavy accumulations, with the heaviest amounts centering
    along a northwest-southeast axis extending from northern Indiana
    to West Virginia. Overnight localized totals of 3-5 inches can be
    expected along this axis. Refer to WPC #999 for additional details
    concerning the near-term heavy rainfall and flash flooding threat
    across this region.

    Across the Southwest, made some minor adjustments based on
    observation trends, including a small expansion of the Slight Risk
    centered over southeastern Arizona.

    Pereira


    Day 2
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO VALLEY...

    ...Midwest and Ohio Valley...

    20Z Update: Continued active setup across the Midwest to Ohio
    Valley will lead to widespread heavy rainfall from multiple
    convective complexes that will also exhibit potential for training
    and back-building over areas of IN/OH during the period. A growing
    consensus within both the CAMs and global deterministic allowed for
    a higher confidence forecast across much of southern Ohio back into
    eastern Indiana to connect with the already forecast MDT risk over
    portions of West Virginia. Latest HREF blended mean QPF depicted a
    long axis of 2-4" totals between areas just east of Indianapolis
    all the way towards Charleston, WV with some of the local maxima
    actually closer to 6-8" when assessing individual deterministic.
    This setup is conducive for these totals with a classic summer
    convective scenario of multiple MCS propagating through a
    persistent northwest to southeast aligned mean flow thanks to a
    squeeze player between the northern periphery of a broad ridge
    across the Southern U.S. and a deep cyclonic gyre spinning up over
    east-central Canada. The combined effort between the two distinct
    upper features will create a mid to upper level "highway" for
    several shortwave impulses to migrate out of the High Plains and
    traverse the central Midwest into the Ohio Valley. The coupling of
    favored jet dynamics and increased large scale forcing from the
    prevalent mid-level vorticity maxima will interact with a suitable thermodynamic environment positioned over the Ohio and Tennessee
    Valley's as noted via some prolific theta_E advection occurring
    during Tuesday afternoon.

    Area PWAT anomalies on the order of 1-2 standard deviations above
    normal will be present across much of the Ohio Valley back into the
    central and southern Midwest providing a sufficient deep, moist
    profile that will be conducive for efficient rainfall processes
    necessary for more formidable heavy rain accumulations.
    Increasingly backed flow in the lower boundary layer will occur
    over portions of IN/OH thanks to the disturbance advecting into the
    area by later Tuesday leading to a period of training and/or back-
    building convection after initiation, carrying through at least the
    first half of the evening hours. Remnant cold pool from today's
    convection will be a focal point for the training potential and the
    recent CAMs have been locking in on the area extending from eastern
    IN into southwestern WV as the most likely orientation and location
    of the surface feature in question. This correlated to some
    significant rainfall forecasts from the 12z CAMs suite within that
    zone leading to enhanced neighborhood probabilities for both the
    3" (50-80%) and >5" (30-50%) thresholds during the period. 24hr
    10yr-ARI exceedance probs across the same areas are fairly robust
    with a bullseye of 40-60% located between Muncie, IN to Wilmington,
    OH with the same area already seeing 20-35% probs for even the
    100yr-ARI exceedance threshold, a testament to the anticipated
    magnitude of heavy rainfall for the coming setup.

    In coordination with the OHRFC and local WFO's from IN/OH/WV, the
    previous MDT risk was expanded across portions of eastern Indiana,
    the southern-third of Ohio, into western side of WV, mainly along
    and west of the I-79 corridor. Significant flash flooding is likely
    in these areas with widespread flash flood warnings and rapid
    riverine responses likely to cause issues lingering through the
    rest of the week as the overall setup extends beyond the D2 period.

    Kleebauer

    ...Southern Arizona...

    20Z Update: Latest CAMs and associated HREF continue to pin another
    round of heavy rainfall across the southern and southeastern
    portion of AZ thanks to elevated PWATs between 2-3 deviations above
    normal and a very buoyant environment conducive for heavy rainfall
    development. Prob fields for >1" remain very high (70-90%) over the
    area extending from Cochise county over into the eastern half of
    Pima, extending north towards the I-10 corridor in Tuscon. I-19
    remains the focal point for heavier rainfall, however the ridge
    positioning would invite more of southeast AZ into the picture for
    locally heavy rains, including the Huachuca Mountains that will
    likely be another focus for development as we move into Tuesday
    afternoon. The previous SLGT risk forecast was maintained as the
    signal remains consistent with little run-to-run variability.

    Kleebauer

    ..Previous Discussion..

    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases from
    Monday to Tuesday as an upper level trough settles in to the CA
    Coast and ridging near the Four Corners weakens, which should lead
    to less mid-level capping and broader convective coverage.

    Roth


    Day 3
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE OHIO VALLEY, MIDWEST, & CENTRAL HIGH PLAINS...

    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...

    20Z Update: The previous SLGT risk with high-end SLGT risk
    potential remains across portions of the Ohio Valley as the signal
    for heavy rainfall continues over the region, despite continued
    inconsistencies within the global deterministic. The setup on
    exactly where the heaviest rainfall will focus is still on the
    tricky side as the location of the remnant cold pool from
    Tuesday/Wednesday AM convection will be a focal point for where the
    next round of convection will transpire. There is a growing
    likelihood that the area extending from northern KY through
    southern OH will be the primary area of interest when you couple
    with the expected heavy rains the prior periods leading to priming,
    or even already flooded areas before the next round occurs. The
    global deterministic is all over the place with where the heavier
    rains will occur, but one consistency is the areal expanse of heavy
    convection is broader than the previous periods leading to a much
    larger SLGT risk situated from the Midwest through much of the Ohio
    Valley.

    The prospects for a risk upgrade where any overlap of heavy
    rainfall is high, so the expectation is for an addition of a higher
    risk probable at this point in time. That said, we need a bit more
    consensus from ensembles and deterministic, alike to prompt an
    upgrade over a particular area. The most notable area for a
    consideration to an upgrade is likely the southwestern quadrant of
    WV into southeast OH where complex terrain and funneling within
    the valleys west of I-79 and within the bounds of I-64 have the
    greatest potential just based off the National Blend and modest
    probs for >1" and >2" thresholds. For now, felt it was prudent to
    provide another round or two of model runs before inserting any
    upgrades, but will make mention that the opportunity in the future
    is higher than normal for continued significant flash flooding and
    an expected upgrade.

    Kleebauer

    ..Previous Discussion..

    Early to mid next week, broad cyclonic flow expected to persist
    across the northern tier of the Lower 48 from the Northern
    Plains/Upper MS Valley, eastward through the Midwest/Great Lakes
    and into the Northeast, to the south of a closed mid-level low that
    has shifted into Quebec. A frontal boundary will lie along the
    southern periphery of this broad trough from portions of the
    Northern and Central Plains into portions of the Ohio Valley and
    Appalachians. Embedded shortwaves in this broad cyclonic flow will
    accentuate lift in the vicinity of this front where PW values are
    expected to rise to ~2" ahead of each set of shortwaves and low-
    level confluence is expected.

    The guidance is showing a growing signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly
    rain amounts to 3" and local totals to 6" remain possible. A high
    end Slight Risk lies across portions of the region due to previous
    days of rains further saturating soils. There is a bit of spread of
    the heavy rain signal seen in the guidance, with the 00z UKMET/00z
    ECMWF the lowest and the 00z Canadian Regional/RDPS the highest.
    Due to the uncertainty in the heavy rain signal, held off on a
    Moderate Risk for the time being.

    Roth

    ..The West/Central & Northern Plains...

    20Z Update: The previous SLGT risk forecast was generally unchanged
    from the overnight issuance as models remains steadfast in their
    presentation of heavy rainfall situated across southeastern AZ.
    This area will have seen multiple days of heavy rains leading into
    the period, so the prospects for scattered flash flood concerns are
    elevated relative to normal. Totals of 1-2", locally higher are
    forecast across the area with multiple areas across the Interior
    West and the Northern Plains also likely to see similar precip
    outputs thanks to a favorable setup across the western half of the
    CONUS. FFG's are much higher outside the southern deserts, so the
    threat for more significant impacts are lower, so a broad MRGL
    exists elsewhere to account for the threat.

    Kleebauer

    ..Previous Discussion..

    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and Plains when compared to previous days as the mid-level cap
    further erodes. Above average precipitable water values slowly
    shift northward through the region. While there continues to be low
    confidence with the details, locally heavy rains with the
    potential of 2.5" an hour amounts could be problematic. Urban
    areas, arroyos/dry washes, box/slot canyons, and burn scars would
    be most at risk for flash flooding. A Slight Risk was introduced
    across southeast AZ.

    Roth


    Day 4 and Day 5

    Valid 12Z Thu Aug 13 2026 - 12Z Sat Aug 15 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FROM THE MID-
    MISSOURI VALLEY THROUGH THE OHIO VALLEY, PORTIONS OF THE HIGH
    PLAINS, AND SOUTHEASTERN ARIZONA TO WESTERN NEW MEXICO ON
    THURSDAY...

    20Z Update...
    The 12Z guidance did not present any reason to make significant
    changes to the previous outlook. Therefore, made only minor
    adjustments.

    Pereira

    Previous Discussion...
    Out west, the monsoon will have one final
    day where moisture across Arizona and New Mexico will be well above
    normal. Flattening upper level troughing that lifts northeastward
    away from Arizona and southern New Mexico should allow the showers
    and storms that form in that region to reduce the total atmospheric
    moisture quite a bit, with no replenishment overnight Thursday
    night. The Slight risk in this region follows where numerous prior
    days heavy rains impacted portions of southeastern Arizona and
    western New Mexico. Low FFGs still support widely scattered
    instances of flash flooding due to highly favorable hydrology
    (hydrophobic soils) in the flood prone areas.

    A large Slight Risk was introduced for much of the Front Ranges and
    High Plains from the Sangre de Cristos of northern New Mexico north
    through southeastern Montana. The aforementioned lifting upper
    level trough will have the opposite effect as further south, namely
    greatly increasing convective coverage and intensity in this
    generally flood prone region. A potent upper level shortwave riding northeastward along the eastern periphery of the positively tilted
    longwave trough will locally greatly increase convective coverage
    across the Plains of Colorado in particular. With a potent easterly
    low level jet advecting deep tropical moisture that has been in
    place across the eastern half of the country westward, the storms
    will run into an increasingly moisture rich and unstable
    environment. This will support backbuilding and training storms as
    the fuel for the storms is continually replenished. Further
    upgrades to the risk outlook are possible in the coming days,
    especially should urban areas such as Denver remain in the forecast
    for multiple inches of rain Thursday afternoon and evening.

    Finally, the Slight across portions of the Midwest and lower Ohio
    Valley was expanded east through much of West Virginia. With
    continued rain for a third consecutive day expected into West
    Virginia, despite somewhat lower total expected rainfall, the flood
    prone nature of the terrain there supports a higher risk for
    flooding. Downstream along the Ohio River, they will also be
    enduring the latest of a multi-day rainfall event on Thursday, also
    suggesting that FFGs by Thursday will be much lower across much of
    the Ohio Valley and supporting the Slight Risk upgrade. A plume of
    deep tropical moisture will bank itself along a stationary front
    suck just south of the southern ends of Lakes Michigan and Erie.
    This will support backbuilding and training of convection from Iowa
    straight through to West Virginia in the form of numerous rounds of
    storms that each follow a similar track, resulting in repeating
    storms. Some areas in this zone too may require risk upgrades as
    the event draws closer and moves into CAMS range.

    By Day 5/Friday, the signals for heavy rain become much more
    diffuse and spread out, with a few areas still highlighted,
    including northeastern Colorado, much of Iowa, and southern West
    Virginia. All 3 of these areas may have been hit hard with heavy
    rains on Day 4/Thursday, but since it's highly likely there will be
    large changes in both the placement and intensity of the heavy rain
    signals in each of these areas, have opted to keep all 3 in a
    Marginal risk for now, albeit a higher end one. Slight Risks will
    definitely be considered should these signals remain in future
    forecasts.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!7oNzfea8e3SoxKYDQz7k_C-gjw5T5o1P1jW8QlJYHZqY54ZhqRObmhO85BPbsB1Ck7aVbYConC8uQPVh1dLuVDG91kk$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!7oNzfea8e3SoxKYDQz7k_C-gjw5T5o1P1jW8QlJYHZqY54ZhqRObmhO85BPbsB1Ck7aVbYConC8uQPVh1dLu0jl0Gfk$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!7oNzfea8e3SoxKYDQz7k_C-gjw5T5o1P1jW8QlJYHZqY54ZhqRObmhO85BPbsB1Ck7aVbYConC8uQPVh1dLuVO36Z6I$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 11 07:14:56 2026
    FOUS30 KWBC 110714
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    314 AM EDT Tue Aug 11 2026

    Day 1
    Valid 12Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE ARE A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO VALLEY...


    ...Midwest/Ohio Valley/Mid-Atlantic States...
    The general flow pattern remains fairly static since yesterday.
    The equatorward edge of the Westerlies is forecast to lie from the
    Northern Plains into portions of the Ohio Valley and Mid- Atlantic
    States where there is also low- level confluence, difluent 1000-500
    hPa thickness, and an instability gradient to focus organized
    convection. Precipitable water values are forecast to be 2"+ in
    spots. Hourly rain amounts to 3" and local totals to 6" remain
    possible given the available ingredients. Previous days' rains over
    these areas have saturated the soils further across portions of
    northern IL/northern IN/OH/WV/southwest PA. When combined with the
    general very flashy nature of the rivers/terrain of West Virginia,
    the Moderate Risk level continues to make sense. Recent guidance
    led to some southward shift/expansion in the Slight/Moderate Risk
    areas. An eastward expansion of the Slight Risk area into Richmond/ Baltimore/Washington DC was made as several members of the global
    guidance had a heavy rain signal over or very near the region which
    received heavy rainfall on Monday.


    ...Southern Arizona...
    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases as an
    upper level trough settles in to the CA Coast and ridging near the
    Four Corners weakens, which should lead to less mid-level capping
    and broader convective coverage.

    Roth


    Day 2
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS IN AND NEAR PORTIONS
    OF THE OHIO VALLEY AND SOUTHEAST ARIZONA...


    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...
    On Wednesday, broad cyclonic flow expected to persist across the
    northern tier of the Lower 48 from the Northern Plains/Upper MS
    Valley, eastward through the Midwest/Great Lakes and into the
    Northeast, to the south of a closed mid-level low that has shifted
    into Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough from portions of the Northern and
    Central Plains into portions of the Ohio Valley and Appalachians.
    Embedded shortwaves in this broad cyclonic flow will accentuate
    lift in the vicinity of this front where PW values are expected to
    rise to ~2" ahead of each set of shortwaves and low- level
    confluence is expected.

    The guidance continues to show a signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly rain
    amounts to 3" and local totals to 6" remain possible. A high end
    Slight Risk lies across portions of the region due to previous days
    of rains further saturating soils. Spread remains in the guidance
    concerning QPF magnitude, so allowed to existing risk levels to
    ride, though there was some southward nudging to the Slight Risk
    positioning based on the recent guidance.


    ..The West/Central & Northern High Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and High Plains when compared to previous days as the mid-level
    cap further erodes, with upslope flow developing across portions of
    the High Plains. Above average precipitable water values slowly
    shift northward through the Intermountain West. While there
    continues to be low confidence with the details, locally heavy
    rains with the potential of 2.5" an hour amounts (particularly
    across southeast AZ) could be problematic. Urban areas,
    arroyos/dry washes, box/slot canyons, and burn scars would be most
    at risk for flash flooding. A Slight Risk from continuity remains
    across southeast AZ.

    Roth


    Day 3
    Valid 12Z Thu Aug 13 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST, OHIO VALLEY, HIGH PLAINS, & THE SOUTHWEST...


    Midwest/Ohio Valley...
    A sharpening upper level trough extending south of a deep layer
    cyclone in Quebec forces the leading edge of the Westerlies to
    extend from the Central/Northern Plains through the Ohio Valley
    into the southern Mid-Atlantic States. Enough moisture,
    instability, and effective bulk shear should exist for cell
    organization. Given the moisture available (precipitable water
    values of 2"+), hourly rain amounts to 3" with local totals to 6"
    would be possible. Continuity was fairly well maintained in this
    region.


    High Plains...
    Upslope flow behind a front and ahead of a surface low combined
    with a broadening Western trough leads to increased moisture
    pooling and instability across the region and leads to minimal, if
    any, mid-level capping. The guidance brings 1.25-1.75"
    precipitable water values into portions of eastern MT, eastern WY,
    and eastern CO which would approach record levels for any time of
    the year. ML CAPE could rise above 2000 J/kg. There's an
    antiparallel flow relationship between the low-level upslope and
    expected convective propagation, which should lead to high
    precipitation efficiency wherever storms can cluster/have greater
    coverage. There are a couple areas near the WY/CO/NE border
    junction and irregular WY/MT/SD/ND border junction where the
    guidance has higher amounts. Given the favorable ingredients for
    heavy rainfall, believe the Slight Risk is higher end in those
    areas. Risk areas were generally maintained from continuity.
    Hourly rain amounts to 3" with local totals to 6" can't be ruled
    out where cell stall, backbuild, merge, or train.


    Intermountain West...
    A broadening upper level trough brings an increasing south-
    southwest low-level flow to portions of the region and cooling
    aloft. Precipitable water values exceed 1" in spots, with 1.5-2"
    values across southern AZ. Some areas could see ML CAPE rise above
    1000 J/kg. Enough effective bulk shear could exist for cell organization/training but it's unclear if enough cell coverage will
    exist, outside of Southeast AZ. Risk areas were generally
    maintained from continuity. Hourly rain amounts to 2" are possible
    where cells train and/or merge. This would be most problematic in
    burn scars, urban areas, box/slot canyons, and arroyos/dry washes.

    Roth


    Day 4 and Day 5
    Valid 12Z Fri Aug 14 2026 - 12Z Sun Aug 16 2026

    ...THERE ARE SLIGHT RISKS FOR EXCESSIVE RAINFALL FOR PORTIONS OF
    THE FRONT RANGES AND PLAINS OF COLORADO AS WELL AS FOR PORTIONS OF
    THE UPPER MIDWEST ON FRIDAY...

    ...Colorado and Adjacent Areas...
    An easterly low level jet branching off of broad southerly flow up
    the Plains will support a combination of upslope and convective
    rainfall across much of northern Colorado on Friday. PWATs near the
    Kansas border will approach 1.75 inches, lowering to around 1 inch
    into the Rockies behind the Front Range. This ample moisture will
    funnel north and west ahead of a large upper level trough over the
    West Coast. Upper level shortwaves will also support more
    widespread convective development across much of Colorado. A Slight
    Risk area was introduced for the potential for flooding from these
    storms, since many of them will be tied to the local terrain, but
    still being refueled by the easterly low level jet of moisture into
    the Front Ranges.


    ...Upper Midwest...
    A small Slight Risk area was introduced for portions of eastern
    Iowa, far southeastern Minnesota, southwest Wisconsin, and
    northwestern Illinois with this update. A strong warm front with
    PWATs over 2 inches in many areas will support plentiful convection
    across this region. FFGs in the area are generally around 2 inches
    per hour, lower in any urban areas. Thus, confidence has increased
    given these very favorable factors to introduce a Slight at this
    time. The 00Z EC favors this area for heavier rain, which will
    ultimately be dependent on how fast the warm front pushes
    northeastward into Wisconsin.


    ...Day 5/Saturday...
    The warm front pushing northeast into Wisconsin will favor
    continued heavy rainfall into this region from the ongoing
    storms/MCS that begins Friday. Given how far out this is, have
    opted to hold at just a Marginal for now, as the track and
    intensity of MCSs at this range are frequently far off from what
    ends up happening. That said, the abundant moisture, strong
    forcing, and low FFGs into Wisconsin would support Slight Risk
    level impacts. Any southward shift of the heaviest rains may impact
    the Chicagoland area more significantly, so that will have to be
    monitored in the coming days.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!8BnHJpwYKJ_xks44qEehIQT5KP6FGfYZeXtpWYM4k-U-zKUHY1mJ5nd7lY-LGY4nZ536lzvqZWy2ahwIwdstOFq9EqU$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!8BnHJpwYKJ_xks44qEehIQT5KP6FGfYZeXtpWYM4k-U-zKUHY1mJ5nd7lY-LGY4nZ536lzvqZWy2ahwIwdst2-O26Pk$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!8BnHJpwYKJ_xks44qEehIQT5KP6FGfYZeXtpWYM4k-U-zKUHY1mJ5nd7lY-LGY4nZ536lzvqZWy2ahwIwdstcYJbg6Y$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 11 13:49:28 2026
    FOUS30 KWBC 111349
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    949 AM EDT Tue Aug 11 2026

    Day 1
    Valid 1340Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO VALLEY...

    ...Midwest/Ohio Valley/Mid-Atlantic States...
    1330Z Update: Have issued non-routine update to the Day 1 ERO that
    will account for the most recent MCS (more widespread convection)
    that will be traversing central and southern OH and western WV this
    morning. The latest Flash Flood Guidance (FFG) from the OHRFC is
    quite low -- down to a quarter inch within both the 1/3 hour
    timeframes. This is indicative of the highly saturated soils based
    on the heavy rainfall over the past 24 hours. For further details,
    please see the latest Mesoscale Precipitation Discussion (MPD
    #1007) that extends across this Moderate Risk area, including the
    expanded area to the north, where additional flash flooding is
    likely through 18-19Z.

    Hurley

    Previous discussion below..

    The general flow pattern remains fairly static since yesterday.
    The equatorward edge of the Westerlies is forecast to lie from the
    Northern Plains into portions of the Ohio Valley and Mid- Atlantic
    States where there is also low- level confluence, difluent 1000-500
    hPa thickness, and an instability gradient to focus organized
    convection. Precipitable water values are forecast to be 2"+ in
    spots. Hourly rain amounts to 3" and local totals to 6" remain
    possible given the available ingredients. Previous days' rains over
    these areas have saturated the soils further across portions of
    northern IL/northern IN/OH/WV/southwest PA. When combined with the
    general very flashy nature of the rivers/terrain of West Virginia,
    the Moderate Risk level continues to make sense. Recent guidance
    led to some southward shift/expansion in the Slight/Moderate Risk
    areas. An eastward expansion of the Slight Risk area into Richmond/ Baltimore/Washington DC was made as several members of the global
    guidance had a heavy rain signal over or very near the region which
    received heavy rainfall on Monday.

    ...Southern Arizona...
    Southeast AZ remains most at risk for more persistent heavy
    rainfall, so left the Slight Risk intact. Across the Great Basin,
    the Marginal Risk was broadened as moisture subtly increases as an
    upper level trough settles in to the CA Coast and ridging near the
    Four Corners weakens, which should lead to less mid-level capping
    and broader convective coverage.

    Roth


    Day 2
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS IN AND NEAR PORTIONS
    OF THE OHIO VALLEY AND SOUTHEAST ARIZONA...

    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...
    On Wednesday, broad cyclonic flow expected to persist across the
    northern tier of the Lower 48 from the Northern Plains/Upper MS
    Valley, eastward through the Midwest/Great Lakes and into the
    Northeast, to the south of a closed mid-level low that has shifted
    into Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough from portions of the Northern and
    Central Plains into portions of the Ohio Valley and Appalachians.
    Embedded shortwaves in this broad cyclonic flow will accentuate
    lift in the vicinity of this front where PW values are expected to
    rise to ~2" ahead of each set of shortwaves and low- level
    confluence is expected.

    The guidance continues to show a signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly rain
    amounts to 3" and local totals to 6" remain possible. A high end
    Slight Risk lies across portions of the region due to previous days
    of rains further saturating soils. Spread remains in the guidance
    concerning QPF magnitude, so allowed to existing risk levels to
    ride, though there was some southward nudging to the Slight Risk
    positioning based on the recent guidance.

    ..The West/Central & Northern High Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and High Plains when compared to previous days as the mid-level
    cap further erodes, with upslope flow developing across portions of
    the High Plains. Above average precipitable water values slowly
    shift northward through the Intermountain West. While there
    continues to be low confidence with the details, locally heavy
    rains with the potential of 2.5" an hour amounts (particularly
    across southeast AZ) could be problematic. Urban areas,
    arroyos/dry washes, box/slot canyons, and burn scars would be most
    at risk for flash flooding. A Slight Risk from continuity remains
    across southeast AZ.

    Roth


    Day 3
    Valid 12Z Thu Aug 13 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST, OHIO VALLEY, HIGH PLAINS, & THE SOUTHWEST...

    Midwest/Ohio Valley...
    A sharpening upper level trough extending south of a deep layer
    cyclone in Quebec forces the leading edge of the Westerlies to
    extend from the Central/Northern Plains through the Ohio Valley
    into the southern Mid-Atlantic States. Enough moisture,
    instability, and effective bulk shear should exist for cell
    organization. Given the moisture available (precipitable water
    values of 2"+), hourly rain amounts to 3" with local totals to 6"
    would be possible. Continuity was fairly well maintained in this
    region.

    High Plains...
    Upslope flow behind a front and ahead of a surface low combined
    with a broadening Western trough leads to increased moisture
    pooling and instability across the region and leads to minimal, if
    any, mid-level capping. The guidance brings 1.25-1.75"
    precipitable water values into portions of eastern MT, eastern WY,
    and eastern CO which would approach record levels for any time of
    the year. ML CAPE could rise above 2000 J/kg. There's an
    antiparallel flow relationship between the low-level upslope and
    expected convective propagation, which should lead to high
    precipitation efficiency wherever storms can cluster/have greater
    coverage. There are a couple areas near the WY/CO/NE border
    junction and irregular WY/MT/SD/ND border junction where the
    guidance has higher amounts. Given the favorable ingredients for
    heavy rainfall, believe the Slight Risk is higher end in those
    areas. Risk areas were generally maintained from continuity.
    Hourly rain amounts to 3" with local totals to 6" can't be ruled
    out where cell stall, backbuild, merge, or train.

    Intermountain West...
    A broadening upper level trough brings an increasing south-
    southwest low-level flow to portions of the region and cooling
    aloft. Precipitable water values exceed 1" in spots, with 1.5-2"
    values across southern AZ. Some areas could see ML CAPE rise above
    1000 J/kg. Enough effective bulk shear could exist for cell organization/training but it's unclear if enough cell coverage will
    exist, outside of Southeast AZ. Risk areas were generally
    maintained from continuity. Hourly rain amounts to 2" are possible
    where cells train and/or merge. This would be most problematic in
    burn scars, urban areas, box/slot canyons, and arroyos/dry washes.

    Roth


    Day 4 and Day 5
    Valid 12Z Fri Aug 14 2026 - 12Z Sun Aug 16 2026

    ...THERE ARE SLIGHT RISKS FOR EXCESSIVE RAINFALL FOR PORTIONS OF
    THE FRONT RANGES AND PLAINS OF COLORADO AS WELL AS FOR PORTIONS OF
    THE UPPER MIDWEST ON FRIDAY...

    ...Colorado and Adjacent Areas...

    An easterly low level jet branching off of broad southerly flow up
    the Plains will support a combination of upslope and convective
    rainfall across much of northern Colorado on Friday. PWATs near the
    Kansas border will approach 1.75 inches, lowering to around 1 inch
    into the Rockies behind the Front Range. This ample moisture will
    funnel north and west ahead of a large upper level trough over the
    West Coast. Upper level shortwaves will also support more
    widespread convective development across much of Colorado. A Slight
    Risk area was introduced for the potential for flooding from these
    storms, since many of them will be tied to the local terrain, but
    still being refueled by the easterly low level jet of moisture into
    the Front Ranges.

    ...Upper Midwest...

    A small Slight Risk area was introduced for portions of eastern
    Iowa, far southeastern Minnesota, southwest Wisconsin, and
    northwestern Illinois with this update. A strong warm front with
    PWATs over 2 inches in many areas will support plentiful convection
    across this region. FFGs in the area are generally around 2 inches
    per hour, lower in any urban areas. Thus, confidence has increased
    given these very favorable factors to introduce a Slight at this
    time. The 00Z EC favors this area for heavier rain, which will
    ultimately be dependent on how fast the warm front pushes
    northeastward into Wisconsin.

    ...Day 5/Saturday...

    The warm front pushing northeast into Wisconsin will favor
    continued heavy rainfall into this region from the ongoing
    storms/MCS that begins Friday. Given how far out this is, have
    opted to hold at just a Marginal for now, as the track and
    intensity of MCSs at this range are frequently far off from what
    ends up happening. That said, the abundant moisture, strong
    forcing, and low FFGs into Wisconsin would support Slight Risk
    level impacts. Any southward shift of the heaviest rains may impact
    the Chicagoland area more significantly, so that will have to be
    monitored in the coming days.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!-fDqaWAr0wcVtP3m3M_Lv6_z1tgnPpcal3qDzbULqAweJ3xHgfeVrD-MBxLkkRqCyC0h9uIBGQuiEvp040-IXpfKx64$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!-fDqaWAr0wcVtP3m3M_Lv6_z1tgnPpcal3qDzbULqAweJ3xHgfeVrD-MBxLkkRqCyC0h9uIBGQuiEvp040-I8ca9YUw$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!-fDqaWAr0wcVtP3m3M_Lv6_z1tgnPpcal3qDzbULqAweJ3xHgfeVrD-MBxLkkRqCyC0h9uIBGQuiEvp040-Isl6uLOw$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)
  • From COD Weather Processor @1:2320/107 to All on Tue Aug 11 15:53:46 2026
    FOUS30 KWBC 111553
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1153 AM EDT Tue Aug 11 2026

    Day 1
    Valid 16Z Tue Aug 11 2026 - 12Z Wed Aug 12 2026

    ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE OHIO VALLEY...

    ...Midwest/Ohio Valley/Mid-Atlantic States...
    1330Z Update: Have issued non-routine update to the Day 1 ERO that
    will account for the most recent MCS (more widespread convection)
    that will be traversing central and southern OH and western WV this
    morning. The latest Flash Flood Guidance (FFG) from the OHRFC is
    quite low -- down to a quarter inch within both the 1/3 hour
    timeframes. This is indicative of the highly saturated soils based
    on the heavy rainfall over the past 24 hours. For further details,
    please see the latest Mesoscale Precipitation Discussion (MPD
    #1007) that extends across this Moderate Risk area, including the
    expanded area to the north, where additional flash flooding is
    likely through 18-19Z.

    Hurley

    Previous discussion below..

    The general flow pattern remains fairly static since yesterday.
    The equatorward edge of the Westerlies is forecast to lie from the
    Northern Plains into portions of the Ohio Valley and Mid- Atlantic
    States where there is also low- level confluence, difluent 1000-500
    hPa thickness, and an instability gradient to focus organized
    convection. Precipitable water values are forecast to be 2"+ in
    spots. Hourly rain amounts to 3" and local totals to 6" remain
    possible given the available ingredients. Previous days' rains over
    these areas have saturated the soils further across portions of
    northern IL/northern IN/OH/WV/southwest PA. When combined with the
    general very flashy nature of the rivers/terrain of West Virginia,
    the Moderate Risk level continues to make sense. Recent guidance
    led to some southward shift/expansion in the Slight/Moderate Risk
    areas. An eastward expansion of the Slight Risk area into Richmond/ Baltimore/Washington DC was made as several members of the global
    guidance had a heavy rain signal over or very near the region which
    received heavy rainfall on Monday.

    Roth

    ...Cen-Srn Rockies...4 Corners...Cen Great Basin...Southwest...
    1600 UTC Update: Southeast AZ and southwest NM remains most at risk
    for more persistent heavy rainfall, and as such the Slight Risk
    from yesterday's Day 2 ERO remained intact based off last night's
    00Z and today's 12Z guidance. Across the Great Basin, the Marginal
    Risk was broadened as moisture subtly increases as an upper level
    trough settles in to the CA Coast and ridging near the Four Corners
    weakens, which should lead to less mid-level capping and broader
    convective coverage.

    Hurley/Roth


    Day 2
    Valid 12Z Wed Aug 12 2026 - 12Z Thu Aug 13 2026

    ...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS IN AND NEAR PORTIONS
    OF THE OHIO VALLEY AND SOUTHEAST ARIZONA...

    ...Portions of the Plains/Ohio Valley/Midwest/Corn Belt...
    On Wednesday, broad cyclonic flow expected to persist across the
    northern tier of the Lower 48 from the Northern Plains/Upper MS
    Valley, eastward through the Midwest/Great Lakes and into the
    Northeast, to the south of a closed mid-level low that has shifted
    into Quebec. A frontal boundary will lie along the southern
    periphery of this broad trough from portions of the Northern and
    Central Plains into portions of the Ohio Valley and Appalachians.
    Embedded shortwaves in this broad cyclonic flow will accentuate
    lift in the vicinity of this front where PW values are expected to
    rise to ~2" ahead of each set of shortwaves and low- level
    confluence is expected.

    The guidance continues to show a signal for heavy rainfall that at
    the moment is most centered over the NE Sand Hills. Due to the
    hydrology there, thought it prudent to maintain the inherited
    Marginal Risk. When looking at the ingredients, organized
    convection looks most likely near portions of the Ohio Valley and
    the Corn Belt Wednesday into Thursday morning, where the better
    1000-500 hPa thickness difluence is forecast to remain. Hourly rain
    amounts to 3" and local totals to 6" remain possible. A high end
    Slight Risk lies across portions of the region due to previous days
    of rains further saturating soils. Spread remains in the guidance
    concerning QPF magnitude, so allowed to existing risk levels to
    ride, though there was some southward nudging to the Slight Risk
    positioning based on the recent guidance.

    ..The West/Central & Northern High Plains...
    A broadening upper level trough is forecast across portions of the
    West and Great Basin Wednesday into Thursday morning. Broad
    Marginal Risk areas exist near and ahead of this upper level trough
    for portions of the Southwest and Great Basin. Increased upper
    level troughing opens the door to strengthening low-level level
    flow and broader convective development/coverage across the West
    and High Plains when compared to previous days as the mid-level
    cap further erodes, with upslope flow developing across portions of
    the High Plains. Above average precipitable water values slowly
    shift northward through the Intermountain West. While there
    continues to be low confidence with the details, locally heavy
    rains with the potential of 2.5" an hour amounts (particularly
    across southeast AZ) could be problematic. Urban areas,
    arroyos/dry washes, box/slot canyons, and burn scars would be most
    at risk for flash flooding. A Slight Risk from continuity remains
    across southeast AZ.

    Roth


    Day 3
    Valid 12Z Thu Aug 13 2026 - 12Z Fri Aug 14 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST, OHIO VALLEY, HIGH PLAINS, & THE SOUTHWEST...

    Midwest/Ohio Valley...
    A sharpening upper level trough extending south of a deep layer
    cyclone in Quebec forces the leading edge of the Westerlies to
    extend from the Central/Northern Plains through the Ohio Valley
    into the southern Mid-Atlantic States. Enough moisture,
    instability, and effective bulk shear should exist for cell
    organization. Given the moisture available (precipitable water
    values of 2"+), hourly rain amounts to 3" with local totals to 6"
    would be possible. Continuity was fairly well maintained in this
    region.

    High Plains...
    Upslope flow behind a front and ahead of a surface low combined
    with a broadening Western trough leads to increased moisture
    pooling and instability across the region and leads to minimal, if
    any, mid-level capping. The guidance brings 1.25-1.75"
    precipitable water values into portions of eastern MT, eastern WY,
    and eastern CO which would approach record levels for any time of
    the year. ML CAPE could rise above 2000 J/kg. There's an
    antiparallel flow relationship between the low-level upslope and
    expected convective propagation, which should lead to high
    precipitation efficiency wherever storms can cluster/have greater
    coverage. There are a couple areas near the WY/CO/NE border
    junction and irregular WY/MT/SD/ND border junction where the
    guidance has higher amounts. Given the favorable ingredients for
    heavy rainfall, believe the Slight Risk is higher end in those
    areas. Risk areas were generally maintained from continuity.
    Hourly rain amounts to 3" with local totals to 6" can't be ruled
    out where cell stall, backbuild, merge, or train.

    Intermountain West...
    A broadening upper level trough brings an increasing south-
    southwest low-level flow to portions of the region and cooling
    aloft. Precipitable water values exceed 1" in spots, with 1.5-2"
    values across southern AZ. Some areas could see ML CAPE rise above
    1000 J/kg. Enough effective bulk shear could exist for cell organization/training but it's unclear if enough cell coverage will
    exist, outside of Southeast AZ. Risk areas were generally
    maintained from continuity. Hourly rain amounts to 2" are possible
    where cells train and/or merge. This would be most problematic in
    burn scars, urban areas, box/slot canyons, and arroyos/dry washes.

    Roth


    Day 4 and Day 5
    Valid 12Z Fri Aug 14 2026 - 12Z Sun Aug 16 2026

    ...THERE ARE SLIGHT RISKS FOR EXCESSIVE RAINFALL FOR PORTIONS OF
    THE FRONT RANGES AND PLAINS OF COLORADO AS WELL AS FOR PORTIONS OF
    THE UPPER MIDWEST ON FRIDAY...

    ...Colorado and Adjacent Areas...

    An easterly low level jet branching off of broad southerly flow up
    the Plains will support a combination of upslope and convective
    rainfall across much of northern Colorado on Friday. PWATs near the
    Kansas border will approach 1.75 inches, lowering to around 1 inch
    into the Rockies behind the Front Range. This ample moisture will
    funnel north and west ahead of a large upper level trough over the
    West Coast. Upper level shortwaves will also support more
    widespread convective development across much of Colorado. A Slight
    Risk area was introduced for the potential for flooding from these
    storms, since many of them will be tied to the local terrain, but
    still being refueled by the easterly low level jet of moisture into
    the Front Ranges.

    ...Upper Midwest...

    A small Slight Risk area was introduced for portions of eastern
    Iowa, far southeastern Minnesota, southwest Wisconsin, and
    northwestern Illinois with this update. A strong warm front with
    PWATs over 2 inches in many areas will support plentiful convection
    across this region. FFGs in the area are generally around 2 inches
    per hour, lower in any urban areas. Thus, confidence has increased
    given these very favorable factors to introduce a Slight at this
    time. The 00Z EC favors this area for heavier rain, which will
    ultimately be dependent on how fast the warm front pushes
    northeastward into Wisconsin.

    ...Day 5/Saturday...

    The warm front pushing northeast into Wisconsin will favor
    continued heavy rainfall into this region from the ongoing
    storms/MCS that begins Friday. Given how far out this is, have
    opted to hold at just a Marginal for now, as the track and
    intensity of MCSs at this range are frequently far off from what
    ends up happening. That said, the abundant moisture, strong
    forcing, and low FFGs into Wisconsin would support Slight Risk
    level impacts. Any southward shift of the heaviest rains may impact
    the Chicagoland area more significantly, so that will have to be
    monitored in the coming days.

    Wegman


    Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt__;!!DZ3fjg!4yN1e7QkxDe4jFSYMKYxa08Fq6aHNFAUQKzO2dDXIQaqdx4x-J-uj3obi_UcOt_i5FER81-5BlKAqHTEd4eHNJq8nzs$
    Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt__;!!DZ3fjg!4yN1e7QkxDe4jFSYMKYxa08Fq6aHNFAUQKzO2dDXIQaqdx4x-J-uj3obi_UcOt_i5FER81-5BlKAqHTEd4eHD3-jpk0$
    Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt__;!!DZ3fjg!4yN1e7QkxDe4jFSYMKYxa08Fq6aHNFAUQKzO2dDXIQaqdx4x-J-uj3obi_UcOt_i5FER81-5BlKAqHTEd4eH5n0IqFE$



    $$

    = = =
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
    --- scorpsmtpd
    * Origin: capitolcityonline.net * KY, USA (1:2320/107)