• HVYRAIN: Excessive Rainfa

    From Mike Powell@618:250/1 to All on Mon Feb 23 08:02:50 2026
    FOUS30 KWBC 230803
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    303 AM EST Mon Feb 23 2026

    Day 1
    Valid 12Z Mon Feb 23 2026 - 12Z Tue Feb 24 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHWESTERN WASHINGTON, ALL OF WESTERN OREGON, AND INTO PORTIONS
    OF NORTHERN CALIFORNIA...

    A deep positively tilted trough extending from British Columbia
    southwest towards the Hawaiian Islands will be flanked on its
    southeast side with a 170 kt southwesterly jet. This jet will be
    aimed at western Washington State for the first half of the day on
    Monday. Meanwhile, a weakening surface low embedded within that
    trough will help direct an atmospheric river (A.R.) which extends
    from the tropics east of Hawaii northeast into the West Coast. As
    the jet streak reorients, a surface low will develop along that
    plume, locally enhancing rainfall rates into southern Oregon and
    northern California Monday night. Meanwhile, snow levels will rise
    to above 8,000 ft. The combination of locally heavy rain as the low
    and its associated cold front move ashore and snowmelt through the
    coastal mountains from northern California through southern
    Washington will likely raise local stream, creek, and river levels
    such that isolated flash flooding is possible, especially in any
    more flood-prone areas. The inherited Marginal Risk was mostly
    unchanged, but a slower southward progression did require some
    trimming of the inherited Marginal Risk area north out of the Bay
    Area, as it no longer looks like meaningful rain will reach that
    far south during this period.

    Wegman


    Day 2
    Valid 12Z Tue Feb 24 2026 - 12Z Wed Feb 25 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    NORTHERN SIERRA NEVADA MOUNTAINS AND ADJACENT FOOTHILLS...

    Few changes were needed to the inherited risk areas across northern
    California. The cold front associated with a low that will move
    inland and dissipate into Oregon will keep a steady stream of
    subtropical Pacific moisture moving into northern California for
    much of the day Tuesday. The rain will be aided, in part, by the
    persistent 150 kt jet, aimed at southwestern Oregon. The rain
    shield looks to stay more over northern California and not get
    quite as far south into the southern Sierras, so the inherited
    Slight and Marginal Risks were trimmed on their south sides. A few
    other notable changes were somewhat of a decrease in total rainfall
    expected, due in part to the expectation of less elevated
    convection than previous forecasts. However, given the recent
    multiple feet of snow that fell into the northern Sierras over the
    past week or two, there is plenty of snow to melt as snow levels on
    Tuesday remain between 8,000 and 9,000 feet across all of the
    northern Sierras. Thus, while confidence in Slight Risk level
    impacts occurring has decreased a bit, there still remains enough
    to maintain the Slight across the northern Sierra Nevada and their
    adjacent foothills. The rain will continue pushing south but
    rapidly diminish in intensity Tuesday night. This combined with
    falling snow levels by Wednesday will end the flash flooding
    threat, though river levels will likely remain elevated through late week.

    Wegman


    Day 3
    Valid 12Z Wed Feb 25 2026 - 12Z Thu Feb 26 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Tue Feb 24 09:12:21 2026
    FOUS30 KWBC 240803
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    303 AM EST Tue Feb 24 2026

    Day 1
    Valid 12Z Tue Feb 24 2026 - 12Z Wed Feb 25 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    NORTHERN SIERRA NEVADA MOUNTAINS AND ADJACENT FOOTHILLS...

    Very few changes were needed to the overall risk areas across
    California and extreme southwest Oregon. Steady moderate rain is
    ongoing from northern California through Oregon and southern
    Washington. An area of surface low pressure that is at the leading
    edge of a plume of moisture originating from the tropics will move
    ashore in Oregon later today. The trailing cold front will guide
    the tropical moisture into northern California, leading to multiple
    hours of steady rain into the northern Coast Ranges, the Klamath
    Ranges, and the northern Sierra Nevada.

    The plume of moisture moving into northern California has also
    brought with it much warmer air. Snow levels have risen to between
    8,000 and 10,000 ft; 8,000 closer to the OR border and 10,000 near
    I-80. These much higher snow levels moving over the mountains that
    have multiple feet of new snow on them from the storms the past
    few weeks is leading to accelerated snow melt. As the rain that has
    already begun in this area falls on the snow pack, much of it will
    be absorbed. However, after multiple hours of rain through the day,
    expect more of it to convert to runoff as combined snow melt and
    rainfall. Thus, instances of flash flooding, particularly in the
    Slight Risk area of the northern Sierra Nevada mountains and
    adjacent foothills to increase into this afternoon and tonight.
    Rain will come to an end late tonight, but the flooding could
    continue beyond that. Somewhat lesser rainfall amounts are expected
    into the northern coastal ranges. There is also significantly less
    snowpack in the coast ranges, so there will be less snow to melt
    and turn into runoff. For these reasons, the Marginal Risk remains in place.

    Wegman


    Day 2
    Valid 12Z Wed Feb 25 2026 - 12Z Thu Feb 26 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman


    Day 3
    Valid 12Z Thu Feb 26 2026 - 12Z Fri Feb 27 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    ...Southeast...

    The Marginal Risk across much of the Southeast was dropped with
    this update. The progressive pattern, good northwesterly flow
    behind the front, very limited instability, drier than average
    soils, and high FFGs will all work against the development of flash
    flooding across the Southeast on Thursday. RRFS and the global
    models suggest a line of storms may develop across Tennessee and
    then sweep south across the Southeast. A line of storms aligned
    orthogonal to the movement of the line rarely, if ever, results in
    flooding. While it's possible for a pair of storms to train over
    the same areas at either end of the line, it seems unlikely that
    will occur over a particularly flood-sensitive area. The flood
    threat is likely less than 5 percent.

    Wegman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Mar 1 09:50:34 2026
    FOUS30 KWBC 010645
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    145 AM EST Sun Mar 1 2026

    Day 1
    Valid 12Z Sun Mar 01 2026 - 12Z Mon Mar 02 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Cook


    Day 2
    Valid 12Z Mon Mar 02 2026 - 12Z Tue Mar 03 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Cook


    Day 3
    Valid 12Z Tue Mar 03 2026 - 12Z Wed Mar 04 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    MISSOURI, ILLINOIS, AND INDIANA...

    A mid/upper wave initially over the Intermountain West/Central
    Rockies will make eastward progress throughout the forecast period,
    fostering surface cyclogenesis in the general vicinity of southern Kansas/Oklahoma. As this occurs, an expansive warm/moist advection
    regime will become established across much of the Mississippi/Lower
    Ohio River Valleys and Missouri Ozarks. A warm front will become
    established in the general vicinity of the I-70 corridor across
    central Illinois, providing a focus for areas of repeating
    rainfall/convection supported by westerly steering flow aloft
    parallel to the front. A few areas of 1-2 inches of rainfall are
    possible. Main uncertainties/mitigating factors for excessive
    rainfall involve 1) extremely dry antecedent conditions in most
    areas, with soil moistures quite low for the time of year, 2)
    uncertainly in location of the warm front and associated precip
    axis (GFS north, EURO/UKMET farther south), and lack of surface-
    based instability for deep convection. Marginal Risk area has been
    maintained for this outlook from the prior D4 ERO, though uncertainties/mitigating factors have led to a substantial
    shrinking of this risk from the prior forecast.

    Cook
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Mon Mar 2 09:25:27 2026
    FOUS30 KWBC 020812
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    312 AM EST Mon Mar 2 2026

    Day 1
    Valid 12Z Mon Mar 02 2026 - 12Z Tue Mar 03 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Cook


    Day 2
    Valid 12Z Tue Mar 03 2026 - 12Z Wed Mar 04 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST AND OHIO VALLEY...

    Models remain consistent in developing an axis of precipitation
    along a warm front extending generally from southeastern Kansas
    eastward along the Ohio River Valley. Models do vary, however, with
    specific location of this front. Areas of 0.5-1.5 inch of rainfall
    are expected within the Marginal Risk area, with a few spots
    exceeding 2 inches possible. The nature of the front (parallel to
    westerly steering flow aloft) will enable some training, and if
    deeper convection can organize (as suggested by the ECMWF), locally
    higher amounts may be observed. Antecedent dry conditions continue
    to remain a limiting factor for flash flood potential as much of
    the region has very high soils and is in drought. A few issues with
    runoff are possible - with potetial maximized in the Marginal Risk
    area during the 00Z-12Z Wed 4 Mar forecast period.

    Cook


    Day 3
    Valid 12Z Wed Mar 04 2026 - 12Z Thu Mar 05 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM NORTH TEXAS NORTHEASTWARD INTO THE MID-MISSISSIPPI VALLEY...

    Low-level warm advection will intensify across the southern Plains
    and Ozarks as a mid-level wave approaches the central Plains
    (while taking a neutral tilt) throughout the forecast period. As
    this occurs, low-level cyclogenesis and strengthing of a surface
    cold front over eastern Kansas/Oklahoma will foster areas of deep
    convection that should migrate northeastward across the Marginal
    Risk area. Models suggest that initial convection should
    materialize as scattered clusters within the broader warm conveyor
    from north Texas into Missouri, with a gradual congealing into a forward-propagating complex late in the period. Specific spatial
    details regarding this evolution are unclear, but areas of 2-3.5
    inches of rainfall appear to be likely where cells can repeat/merge
    on a localized basis. Soil moistures/antecedent conditions are
    quite dry, however, casting some doubt on the runoff potential
    across the region. Nevertheless, varied/locally sensitive terrain
    (especially in the Ozarks) and heavy rainfall suggests at least
    isolated runoff issues can be expected. Depending of specific
    convective evolution, a Slight Risk may be needed in portions of
    Missouri in later outlooks.

    Farther northeast (into Indiana and Ohio), the D3 forecast period
    will mark a second consecutive day of potential 1 inch rainfall
    along/near a surface warm front across the region. Overall
    instability profiles remain marginal, but with wetting soils, a
    gradual increase in excessive runoff potential may necessitate a
    Marginal Risk area in later outlooks.

    Cook
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Tue Mar 3 08:38:11 2026
    FOUS30 KWBC 030830
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    330 AM EST Tue Mar 3 2026

    Day 1
    Valid 12Z Tue Mar 03 2026 - 12Z Wed Mar 04 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST AND OHIO VALLEY...

    Models have solidified their agreement in an axis of 1-2 inch
    rainfall totals generally from northeastern Missouri eastward
    through southern Ohio. These totals will coincide with an east-west
    oriented front across the region, with point forecast soundings
    suggesting fairly fast cellular motions and minimal surface-based
    instability. The main contributor for flash flood potential with
    this axis is repeating/training rainfall, though dry antecedent
    conditions remain a mitigating factor for a larger-scale flash
    flood risk. One exception to this is West Virginia - soil
    moistures are relatively wet there compared to points west.
    Rainfall totals may be somewhat lighter there too though (0.5-1.5
    inches), also keeping any flash flood potential isolated.

    Cook


    Day 2 Valid 12Z Wed Mar 04 2026 - 12Z Thu Mar 05 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM NORTH TEXAS NORTHEASTWARD INTO THE OHIO VALLEY...

    Minimal changes are made to the inherited outlook. At the mid-
    levels, an approaching trough will reach the central Plains during
    the forecast period. As this occurs, strengthening, confluent low-
    level flow from north Texas into the Missouri Ozarks will aid in
    moisture transport and eventually deep convective development
    especially during the afternoon/evening hours. That convective
    development will migrate from southwest to northeast within the
    aforementioned warm conveyor, with areas of training/repeating
    possible along with local rainfall totals exceeding 3 inches
    through 12Z Thursday. The collocation of these rainfall totals with varied/sensitive terrain over southwest Missouri/northwest Arkansas
    suggests that higher probabilities and a Slight Risk may need to be
    introduced at some point. Lingering concerns regarding antecedent
    conditions (very dry soils) and eventual convective evolution
    (models exhibiting a slight westward trend over the past 24 hours)
    gives pause on introducing an upgrade at this time, however.
    Current trends suggest that the greatest risk of flash flooding
    will exist along an axis from Fayetteville, AR to Rolla, MO,
    though this axis may change between now and Wednesday
    afternoon/evening.

    Farther northeast, areas of rain (approaching 1-1.5 inch total in
    spots) will develop from southern Illinois eastward through West
    Virginia in similar locations that are expected to receive 1-2
    inches of rain during the D1 forecast period (Tuesday into Tuesday
    night). Soils should continue to moisten during this period, with
    isolated instances of flash flooding remaining possible.

    Cook


    Day 3 Valid 12Z Thu Mar 05 2026 - 12Z Fri Mar 06 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Models are in general agreement that longwave trough will deepen
    across the Intermountain West, spreading southwesterly flow aloft
    over a large part of the Great Plains. Meanwhile, low-level
    moisture advection will aid in an airmass characterized by 1.25-1.5
    inch PW values along and just east of a dryline generally extending
    from near Goodland to near Amarillo. Models depict scattered
    convection developing amid supercellular wind fields Thursday
    afternoon, with a mix of cells and linear segments possible along
    parts of the dryline. Local cell mergers may result in a couple
    spots of 2-3 inch rainfall totals in this regime, though the
    overall footprint of heavier rainfall should be too small to even
    delineate a Marginal Risk area at this timeframe. Antecedent dry conditions/drought are also mitigating factors for flash flood
    potential. This scenario will need to be monitored for any
    potential increase in convective coverage that might necessitate a
    Marginal in later outlooks.

    Cook
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Wed Mar 4 08:23:37 2026
    FOUS30 KWBC 040802
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    302 AM EST Wed Mar 4 2026

    Day 1
    Valid 12Z Wed Mar 04 2026 - 12Z Thu Mar 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE OZARKS...

    Upper air pattern from the Central Rockies to the Ohio Valley
    remains relatively amplified with a deep shortwave trough analyzed
    across CO, slowly ejecting out into the Front Range this evening.
    At the surface, a weak surface reflection remains parked over
    southwest MO with a trailing cold front analyzed back through OK
    into the TX Panhandle. Expected evolution of the entire pattern
    will yield a slow-moving cold frontal approach across the Southern
    Plains with sights downstream on the Mid and Lower-Mississippi
    Valley area as we move into the front half of D1. Defined confluent
    flow within a persistent axis of diffluence across E TX into the
    Mississippi Valley will allow for a continuation of convective
    pulses to develop and propagate northeast along the trailing front
    with a multi-wave complex of thunderstorms expected to impact areas
    from north TX up through eastern OK, northwest AR, eventually
    through southern MO. Relative instability remains modest, at best
    ahead of the trough axis with general theta_E favored environment
    located along and south of the cold front bisecting the above areas.

    PWAT anomalies between 2-3 deviations above normal will enhance
    heavy rain prospects within any cell maturation with a broad axis
    of at least light to moderate rain likely ongoing from later this
    morning, carrying through the afternoon. A brief period of
    generally lighter rainfall is anticipated prior to sunset, however,
    expectation is for round two to develop with the advent of the
    budding 850mb LLJ positioned southeast of the surface low as it
    finally begins to migrate east-northeast from southern MO. The
    multi-wave precip forecast will allow for priming of the dry soils
    currently in place across the Ozarks with forecasts of 3-5" totals
    being projected via the latest CAMs in areas hit multiple times by
    the waves. Widespread 1-2" are forecast surrounding with the
    "bullseye" of precip aligned from far eastern OK up through
    northwest AR into southern MO with the heaviest likely occurring
    over the rugged terrain of the Ozarks between AR and MO. 00z HREF
    neighborhood probs for >3" of rainfall are running between 40-80%
    over the above zone with low-end probs (15-30%) for >5" across
    southern MO, south of I-44. This seems to have a good consensus
    when assessing the more conservative EAS probs with modest
    probabilities (35-60%) for at least 2" running just east of
    Springfield to just west of I-55.

    Despite those drier antecedent conditions, longevity in the threat
    for heavy rainfall given the dual-wave structure of the precip
    field will allow for isolated to scattered flash flood prospects.
    In coordination with the Springfield, MO and Little Rock, AR WFO's,
    a SLGT risk ERO was introduced in the latest update encompassing
    through areas from far eastern OK up through northwest AR into southern MO.

    Kleebauer


    Day 2
    Valid 12Z Thu Mar 05 2026 - 12Z Fri Mar 06 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Kleebauer


    Day 3
    Valid 12Z Fri Mar 06 2026 - 12Z Sat Mar 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHERN PLAINS INTO THE MID-MISSISSIPPI VALLEY...

    Pattern across the western half of the CONUS becomes highly
    amplified as a potent upper trough migrate east off the Pacific
    with sights downstream on the Rockies and eventually the Southern
    and Central Plains as we move into the end of the week and beyond.
    There's still some discrepancy on exactly where the heaviest precip
    will arise as the meridional component of the upper levels will
    certainly open the door for any areas across the Southern Plains
    to Mississippi Valley to experience scattered to widespread heavy
    rainfall prospects with the Southern Plains and Lower Mississippi
    Valley likely the most susceptible to more prolific convective
    modes. Given the positioning of central and east TX up through the
    ArkLaTex within a persistent diffluent upper level regime and the
    best instability maximum located within the fresh Gulf moisture
    advection pattern thanks to prevailing south to southeast flow,
    there is a growing concern for heavy rainfall to initiate and move
    overhead in these general areas. This threat extends further
    northeast into the Mid-Mississippi Valley as noted via precip
    footprint off the latest ensemble blends, including the NBM and
    bias-corrected ensemble. Deterministic is all over the place with
    regards to specifics, however, and with the period outside CAMs
    windows, it's a bit too early for a SLGT risk proposition with
    still some time to discern details as we move closer. The MRGL risk
    inherited was maintained, but expectation for an upgrade is
    relatively high given the nature of the setup.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Wed Mar 4 12:09:22 2026
    FOUS30 KWBC 041600
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1100 AM EST Wed Mar 4 2026

    Day 1
    Valid 16Z Wed Mar 04 2026 - 12Z Thu Mar 05 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE OZARKS AND THE OHIO VALLEY...

    16Z Update...

    Changes for this update include south and eastward expansions of
    the Slight Risk over the Ozarks to account for a generally heavier
    convective footprint over eastern OK up across much of northwest AR
    and southern MO. Multiple rounds of heavy showers and thunderstorms
    across these areas over the next 12 to 18 hours will likely prime
    the otherwise dry soils sufficiently to increase the threat for
    runoff problems and some isolated to potentially scattered areas of
    flash flooding. Increasing CAPE and rather anomalous PWs pooling up
    along a strong frontal zone working in tandem with ejecting
    shortwave energy should favor relatively organized convective
    clusters. The activity later today and tonight will be capable of
    locally training over the same area given favorable deep layer
    steering flow aligning with the frontal placement. Still thinking
    locally 3 to 5 inch rainfall totals which is in good agreement with
    the 12Z HREF probabilistic output.

    An area to closely watch for this evening/overnight will also be
    parts of central and northern TX (including the DFW metropolitan
    area) as there are several 12Z CAM solutions (ARW/ARW2, HRRR and
    RRFS) showing relatively slow-moving and rather discreet pockets of
    convection with high rainfall rates in close proximity to the cold
    front settling down across this region. Antecedent conditions are
    dry, but the high rainfall rates, and slower cell-motions may
    foster locally several inches of rain which certainly would drive a
    threat for at least isolated flash flooding concerns and especially
    if they manifest into a more urbanized environment. As such, the
    Marginal Risk has been broadened down into these ares of central
    and northern TX.

    A Slight Risk has been introduced across portions of the OH Valley
    including southern IN, southern OH, far northern WV and a small
    part of northwest WV where locally a combination of additional
    rounds of heavy rain (1 to 2+ inches) coupled with wet antecedent
    conditions from recent rainfall will foster greater runoff
    concerns. Already many areas this morning have lingering runoff
    problems from last night's 1 to 3 inches of rain that fell, so the
    additional rains will strongly contribute to elevated streamflows
    and runoff concerns.

    Orrison

    Previous discussion...

    Upper air pattern from the Central Rockies to the Ohio Valley
    remains relatively amplified with a deep shortwave trough analyzed
    across CO, slowly ejecting out into the Front Range this evening.
    At the surface, a weak surface reflection remains parked over
    southwest MO with a trailing cold front analyzed back through OK
    into the TX Panhandle. Expected evolution of the entire pattern
    will yield a slow-moving cold frontal approach across the Southern
    Plains with sights downstream on the Mid and Lower-Mississippi
    Valley area as we move into the front half of D1. Defined confluent
    flow within a persistent axis of diffluence across E TX into the
    Mississippi Valley will allow for a continuation of convective
    pulses to develop and propagate northeast along the trailing front
    with a multi-wave complex of thunderstorms expected to impact areas
    from north TX up through eastern OK, northwest AR, eventually
    through southern MO. Relative instability remains modest, at best
    ahead of the trough axis with general theta_E favored environment
    located along and south of the cold front bisecting the above areas.

    PWAT anomalies between 2-3 deviations above normal will enhance
    heavy rain prospects within any cell maturation with a broad axis
    of at least light to moderate rain likely ongoing from later this
    morning, carrying through the afternoon. A brief period of
    generally lighter rainfall is anticipated prior to sunset, however,
    expectation is for round two to develop with the advent of the
    budding 850mb LLJ positioned southeast of the surface low as it
    finally begins to migrate east-northeast from southern MO. The
    multi-wave precip forecast will allow for priming of the dry soils
    currently in place across the Ozarks with forecasts of 3-5" totals
    being projected via the latest CAMs in areas hit multiple times by
    the waves. Widespread 1-2" are forecast surrounding with the
    "bullseye" of precip aligned from far eastern OK up through
    northwest AR into southern MO with the heaviest likely occurring
    over the rugged terrain of the Ozarks between AR and MO. 00z HREF
    neighborhood probs for >3" of rainfall are running between 40-80%
    over the above zone with low-end probs (15-30%) for >5" across
    southern MO, south of I-44. This seems to have a good consensus
    when assessing the more conservative EAS probs with modest
    probabilities (35-60%) for at least 2" running just east of
    Springfield to just west of I-55.

    Despite those drier antecedent conditions, longevity in the threat
    for heavy rainfall given the dual-wave structure of the precip
    field will allow for isolated to scattered flash flood prospects.
    In coordination with the Springfield, MO and Little Rock, AR WFO's,
    a SLGT risk ERO was introduced in the latest update encompassing
    through areas from far eastern OK up through northwest AR into southern MO.

    Kleebauer


    Day 2
    Valid 12Z Thu Mar 05 2026 - 12Z Fri Mar 06 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Kleebauer


    Day 3
    Valid 12Z Fri Mar 06 2026 - 12Z Sat Mar 07 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE SOUTHERN PLAINS INTO THE MID-MISSISSIPPI VALLEY...

    Pattern across the western half of the CONUS becomes highly
    amplified as a potent upper trough migrate east off the Pacific
    with sights downstream on the Rockies and eventually the Southern
    and Central Plains as we move into the end of the week and beyond.
    There's still some discrepancy on exactly where the heaviest precip
    will arise as the meridional component of the upper levels will
    certainly open the door for any areas across the Southern Plains
    to Mississippi Valley to experience scattered to widespread heavy
    rainfall prospects with the Southern Plains and Lower Mississippi
    Valley likely the most susceptible to more prolific convective
    modes. Given the positioning of central and east TX up through the
    ArkLaTex within a persistent diffluent upper level regime and the
    best instability maximum located within the fresh Gulf moisture
    advection pattern thanks to prevailing south to southeast flow,
    there is a growing concern for heavy rainfall to initiate and move
    overhead in these general areas. This threat extends further
    northeast into the Mid-Mississippi Valley as noted via precip
    footprint off the latest ensemble blends, including the NBM and
    bias-corrected ensemble. Deterministic is all over the place with
    regards to specifics, however, and with the period outside CAMs
    windows, it's a bit too early for a SLGT risk proposition with
    still some time to discern details as we move closer. The MRGL risk
    inherited was maintained, but expectation for an upgrade is
    relatively high given the nature of the setup.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Thu Mar 5 08:48:48 2026
    FOUS30 KWBC 051246
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    746 AM EST Thu Mar 5 2026

    Day 1
    Valid 1245Z Thu Mar 05 2026 - 12Z Fri Mar 06 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE OHIO RIVER VALLEY AND THE SOUTHERN PLAINS...

    13z Update: We sent a quick update to expand the Marginal risk
    into southeast OK. Ongoing convection is exhibiting some
    training/backbuilding characteristics this morning. This activity
    is not being handled well by the high res guidance, but with
    recent cloud top cooling, upstream instability, and wind fields
    favorable for backbuilding...it seems probable that this convection
    will persist for at least a few more hours resulting in a
    localized flash flood risk.

    Chenard

    ...Ohio River Valley...

    Potent mid-level shortwave propagation over the Central Plains will
    continue over the course of this evening into D1 with a core axis
    of diffluence centered over the Mid-Mississippi and Ohio Valleys in
    the beginning of the period. Multiple vorticity maxima will eject
    northeast out of the Ozarks area with a stationary front at the
    surface bisecting areas from North TX up through the Ohio River
    Basin. Moisture transport with the setup is pretty much aligned
    parallel to the mean flow leading to more organized convective
    clusters propagating along the front, disseminating some relatively
    solid QPF output from Dallas up through the north-central Ohio
    Valley. Models are in agreement on the shortwave propagation out of
    the Ozarks this evening to migrate northeast with an eventual
    secondary wave of heavy precip impacting areas along the Ohio River
    Basin, including as far west at the confluence of the
    Ohio/Mississippi Rivers and points east-northeast along the Ohio
    River bordering KY/IL/IN/OH. Multi-day rainfall output will place
    areas of IN/OH within another period of rainfall which is already
    causing issues for places south of I-70 in both states.

    Heaviest rainfall is progged to occur to the southwest with the
    signal via the latest 00z HREF really emphasizing the corridor at
    the confluence of the Mississippi/Ohio rivers up through the
    KY/IL/IN border, much of which falling between the 12-21z time
    frame today. Neighborhood probs for >2" are between 40-60% over the aforementioned area with a few deterministic CAMs producing
    between 3-5" over the time frame. Considering the nature of the
    overlap of heavy rainfall occurring tonight and then again in the
    morning/early afternoon, there was enough of a signal to add a MRGL
    risk for the region in question.

    ...Southern Plains...

    Stationary boundary across TX will lift north during the morning
    and afternoon period today with a quick theta_E advection regime
    taking shape across much of the Southern Plains. Upstream trough
    axis pushing through the west will help to re-amplify the flow
    across the South-Central U.S. with a low pressure center forming
    across the Front Range with a trailing dryline maturing across the
    western TX Panhandle up down through southwest TX. Increasing
    ascent within the diffluent axis downstream of the longwave trough, ample instability located downstream of the dryline, and increased bulk
    shear profiles will promote a favorable instance of convective
    development and maintenance of present updrafts. NAEFS PWAT
    percentile forecast is pushing the 99th percentile via
    climatological norms across the region from the Red River, north
    through the western half of OK into southern KS by late this
    afternoon and beyond. This is a testament to the anticipated
    proliferation of convective cells within the favorable environment,
    each of which will be capable of heavy rain cores with hourly rates
    pushing 2-3"/hr at peak intensity as noted via some of the latest
    CAMs. Despite this area signifying higher FFG's due to a dearth of precipitation lately, this setup is conducive for stronger
    convection as noted via the SPC's Slight Risk outlook for severe
    weather focused within that area downstream of the dryline. A low-
    end scenario for flash flooding is the forecast for this particular
    domain just given the deep moist favorability, as well as the
    organized convective pattern likely to exhibit some pretty hefty
    rainfall in localized areas as the cells migrate to the east and
    northeast. A MRGL risk was added for the region encompassing North
    TX up through western OK into southern KS.

    Kleebauer


    Day 2
    Valid 12Z Fri Mar 06 2026 - 12Z Sat Mar 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSISSIPPI VALLEY, INCLUDING THE ARKLATEX...

    ...ArkLaTex to Lower Mississippi Valley...

    Highly amplified pattern across the western CONUS will shift
    eastward over the course of the end of the week and weekend leaving
    a broad axis of convective development downstream over the Southern
    Plains up into the Midwest to the Mississippi Valley. Guidance is
    beginning to come into agreement on the area located from northeast
    TX up through the ArkLaTex to the western half of the Lower
    Mississippi Valley a focal point for heavy, organized convection
    capable of flash flood concerns. Instability and moisture presence
    will not be limited in this synoptic evolution with a robust
    meridional push of favorable theta_E's thanks to a funneling of
    Gulf moisture poleward downstream of the mean trough. Slow-moving
    cold front across the Central and Southern Plains will pick up
    speed by the end of the forecast period with a defined warm sector
    situated from the eastern half of TX up through the Missouri Valley
    with PWAT anomalies pushing 2-3 standard deviations above normal
    for the time frame. Ensemble bias corrected QPF is now pushing over
    2" across the ArkLaTex with the convergence signal strongest over
    the three-state region as the nocturnal LLJ is forecast to nose
    into the area promoting the most favorable axis for organized
    convection and eventual cell mergers after sunset. CAMs are still a
    bit out of range for this threat, however the signals are already
    creeping into the end of their temporal ranges with some already
    showing 2" of precip with more to come across this area of the
    CONUS. This setup is bordering textbook for these kinds of
    convective evolutions and impacts which lends enough favor to
    upgrade the previous MRGL risk inheritance to a SLGT risk for the
    highlighted zones. This setup is one to monitor as short term
    convective trends could adjust the risk positioning further west
    thanks to the overall amplified evolution.

    ...Midwest...

    Amplified pattern to the west will impact the north-central CONUS,
    as well as the wavy stationary front over the Central Plains and
    Mississippi Valley will lift rapidly to the north as a warm front,
    allowing for a steady increase in regional buoyancy and deep
    moisture presence. Upper pattern out west will evolve into a setup
    that splits the main shortwave in two, ejecting a piece of the
    mid-level vortmax rapidly to the northeast leading to lee
    cyclogenesis over western KS, lifting to the northeast. The
    combination of increasing shear and ascent at both the surface and
    aloft will allow for a heavy convective conglomeration to
    materialize over the Missouri River Valley and points east with
    sights on the Midwest with a centroid over IA/Southern WI/Northwest
    IL. The good news is the setup is progged to be moving quickly, so
    any impacts will be short but locally intense. Localized flash
    flood prospects are forecast for the above areas as the convective
    pattern will promote rates between 1-2"/hr at peak intensity,
    enough to approach, and/or eclipse the lower end of the FFG
    thresholds in place. The previous MRGL risk was maintained as a
    result with only minor adjustments made to the east and northeast
    fringes to the risk area.

    Kleebauer


    Day 3
    Valid 12Z Sat Mar 07 2026 - 12Z Sun Mar 08 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
    THE SOUTHERN PLAINS UP THROUGH THE LOWER MISSISSIPPI VALLEY...

    As the longwave pattern across the western half of the CONUS
    materializes and the surface reflections make their headway to the east/northeast, the cold front trailing the primary low moving
    into the Great Lakes will continue its progress through the
    Southern Plains into the Mississippi Valley losing latitude as it
    propagates to the southeast. As the low moves further away and the
    setup begins to lose upper level favor, the cold front is expected
    to "fan out" as it approaches the Gulf coast leading to convective
    alignment along and just ahead of the front to slow its progression
    with the mean flow becoming a bit more parallel to the frontal
    alignment. Moisture and instability will be plentiful with the
    environment primed from a rich Gulf moisture advection regime that
    will take place the previous 48 hrs. Models are in agreement on an
    axis of heavy QPF located from TX to points northeast over portions
    of AR/LA/western TN/northwest MS. There will likely be an area of
    3+" of precip as noted via modest NBM probs for the threshold
    (10-30%) and 90th percentile QPF output pushing over 3" for part of
    east TX into northern LA with widespread 2+" outputs surrounding.

    This setup is notorious for conditions to prime and favor areas
    further southeast just due to the better instability maxima and
    deeper moisture layer ahead of the front naturally positioned
    closer to the Gulf coast. Pending forward propagation speed of the
    cold front, heavy rainfall could very well make a push towards the
    I-10 corridor down by Houston to Lake Charles, but the jury is
    still out for those areas. Higher confidence in heavy rainfall is
    just north of there with the areas of the Piney Woods in east TX up
    through I-20 into LA as the main targets at this juncture. High
    FFG's will likely thwart considerable flood prospects, as well as
    the setup promoting at least steady convective progress to lower
    training concerns. That still doesn't mean those concerns would
    alleviate at least scattered flash flood concerns, but there's
    still more time to assess location specifics before interjecting an
    upgrade at this time. For now, a broad MRGL risk was maintained,
    but the threat will warrant some consideration of an upgrade as we
    move closer in time and get into the CAMs temporal window(s).

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Fri Mar 6 11:06:03 2026
    FOUS30 KWBC 061600
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1100 AM EST Fri Mar 6 2026

    Day 1
    Valid 16Z Fri Mar 06 2026 - 12Z Sat Mar 07 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
    THE LOWER MISSISSIPPI VALLEY, INCLUDING THE ARKLATEX...

    ...16Z Update...
    Minor adjustments overall made to the overnight forecast thinking.
    Based on the 12Z HREF suite, the inhereted Slight Risk was
    extended slightly northward into the Missouri Ozarks which
    partially overlaps with an area of recent heavy rainfall.
    Otherwise, the Marginal Risk in the Ohio Valley was removed as both
    the HREF and RRFS suggest the threat of exceeding an inch of rain
    (around the 1 HR FFG for the area) is below 5%.

    Asherman

    ...Previous Discussion...

    ...ArkLaTex to Lower Mississippi Valley...

    Highly amplified pattern across the western United States will
    shift eastward today and tonight setting up a broad axis of
    convective development downstream over the Southern Plains up into
    the Midwest to the Mississippi Valley. Instability and moisture
    being drawn northward from the Gulf gets in place ahead of an
    approaching cold front that provides a focus for another round of
    storm later today and tonight with heavy rainfall expected in a
    well defined warm sector situated from the eastern half of Texas
    into the Missouri Valley where precipitable water anomalies
    pushing 2 or 3 standard deviations above normal for the time frame
    should be in place. Ensemble bias corrected QPF from 06/00 remained
    over 2 inches across the ArkLaTex with the convergence signal
    strongest over the three-state region as the nocturnal Low Level
    Jet is forecast to nose into the area promoting the most favorable
    axis for organized convection and eventual cell mergers after
    sunset. The previously issued Slight Risk was maintained with only
    minor adjustments based on latest model guidance.

    ...Midwest...

    Amplified pattern to the west will have impacts on the evolution
    and related threat of excessive rainfall over the Upper Midwest as
    a wavy boundary to the south lifts to the north as a warm front
    later today and tonight. The combination of vertical wind shear and
    the approach upper level shortwave will result in a deepening
    surface low over Kansas later today which draws increasing moisture
    and instability into the Upper Midwest later today and
    tonight....resulting in convection capable of producing heavy
    rainfall over the Missouri River Valley and points east. Any risk
    for excessive rainfall should be offset a bit by quick storm
    motion. 00Z HREF and RRFS both ramp up the probability for 1 inch
    of accumulation early in the Day 1 period which moves off to the
    northeast and dissipates this morning...followed by redevelopment
    this evening in central and northeast Iowa. Provided an apron
    around this area to account for uncertainty in where the convection
    redevelops. As a result...the previous Marginal risk was largely
    maintained with only minor adjustments.

    Bann

    Day 2
    Valid 12Z Sat Mar 07 2026 - 12Z Sun Mar 08 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
    THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

    The previously issued Slight risk across portions of Texas into
    Mississippi was maintained given a consistent signal in the
    numerical guidance of a corridor of heavy rainfall. The actual
    extent and magnitude of the flash flood risk remains a bit
    uncertain relating to how quickly activity propagates off to the
    south and east. Some guidance supports a rather quick southward
    propagation of convection, which could keep the flash flood risk
    more isolated in nature. However, the 06/00Z guidance from both the
    HREF and RRFS still maintain be an opportunity for some along axis
    training even with some southward propagation. The HREF probability
    was notably more aggressive with its neighborhood probabilities for
    1 inch per hour rate than was the RRFS...especially at the start
    of the Day 2 period but eventually converge on similar values on
    Saturday afternoon. At that point the RRFS begins to increase
    probabilities of 1 and 2 inch probabilities ahead of the front as
    it sags southward (after the last forecast hour from the HREF). Thus
    think there is enough going for this event to justify maintaining a
    broad Slight risk with this update.

    A Marginal risk was also extended as far north as western NY.
    Plenty of moisture will advect northward along this corridor, with
    as much as 500-1000 j/kg of CAPE as well. Thus while areal
    averaged rainfall is not that impressive, there will be an
    opportunity for locally heavy rates. With saturated conditions
    over portions of the OH Valley, and some snow pack and frozen
    ground over NY...these higher rates could be enough to locally
    result in excess runoff and minor flood concerns.

    Bann

    Day 3
    Valid 12Z Sun Mar 08 2026 - 12Z Mon Mar 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE GULF COAST REGION...

    Deep moisture...instability and the risk of excessive rainfall
    should be confined to a shrinking area as a cold front makes its
    way southward on Sunday. Model guidance showed a corresponding
    decrease in QPF and spaghetti plots from the SREF and the GEFS
    maintaining a few members with probabilities of 2 inches in the 24
    hour period ending at 12Z Monday from eastern Texas eastward. This
    reflected a downward trend in the deterministic QPF. During the
    latter half of the period...Gulf moisture starts to return
    northward over southwestern Texas later in the period...so made a
    westward expansion of the Marginal risk area.

    Bann
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/1 to All on Sat Mar 7 07:52:48 2026
    FOUS30 KWBC 070830
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    330 AM EST Sat Mar 7 2026

    Day 1
    Valid 12Z Sat Mar 07 2026 - 12Z Sun Mar 08 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
    THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

    Maintained the Slight risk area from the Southern Plains into the
    Lower Mississippi Valley and the Upper Texas coast...with an
    expansion that effectively brought the Slight Risk area to the
    Upper Texas coast and nearby Louisiana given the 07/00Z HREF and
    RRFS probabilities for 24 hour rainfall 2-inch and 3-inch
    thresholds. There were even a few neighborhood probabilities
    exceeding 10 percent at the 5 inch threshold. Of course the actual
    extent and magnitude of the flash flood risk remains a bit
    uncertain relating to how quickly activity propagates off to the
    south and east. Some guidance supports a rather quick southward
    propagation of convection, which could keep the flash flood risk
    more isolated in nature. The HREF guidance tended to side with the
    faster solution and the RRFS was slower and was more aggressive
    with its probabilities for 1- and 2-inch per hour rates. At this
    point...tended to favor the HREF guidance and associated models
    although can not entirely rule out the faster solutions.

    A Marginal risk surrounding the Slight Risk area extended north and
    east as far as western New York. There should be plenty of moisture
    advectiving northward along this corridor, with as much as
    500-1000 j/kg. Thus while areal averaged rainfall is not that
    impressive, there will be an opportunity for locally heavy rates.
    With saturated conditions over portions of the Ohio Valley, and
    some snow pack and frozen ground over New York...any enhanced
    rainfall rates could be enough to result in isolated/locally excess
    runoff and minor flood concerns.

    Bann


    Day 2
    Valid 12Z Sun Mar 08 2026 - 12Z Mon Mar 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE GULF COAST REGION...

    Deep moisture...instability and the risk of excessive rainfall
    should be confined to a shrinking area south of an approaching
    cold front on Sunday. Model guidance showed a corresponding
    decrease in QPF and spaghetti plots from the SREF and the GEFS
    maintaining a few members kept neighborhood probabilities of 1 inch
    or greater confined from Louisiana into Georgia with greatest
    clustering from southern Mississippi into central and southern
    Alabama with QPF spaghetti plots showing few members at 2 inch
    amounts in 24 hours from either the SREF ir GEFS. In this portion
    of the Marginal risk...there was good agreement between WPC and the
    CSU machine learning first-guess ERO. The WPC Marginal Risk area
    extended west along the Louisiana and Upper Texas coast if
    deference to the HREF and RRFS runs which lingered some 1+ in per
    hour rainfall along the coast and even some 2 inch per 6 hour
    lingering through at least 08/18Z. In addition...Gulf moisture
    starts to return northward over southwestern Texas later in the
    period...also supporting a westward expansion.

    Bann


    Day 3 Valid 12Z Mon Mar 09 2026 - 12Z Tue Mar 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE SOUTHEAST UNITED STATES...

    The front which had been moving from west to east in the Day 1 and
    Day 2 period will slow its forward motion and become oriented along
    a west to east axis on Monday and the start to inch northward
    Monday afternoon and Monday night. There is a wide range of
    solutions in where convection could fire along that boundary which
    limits confidence. However...confidence is higher in the occurrence
    of showers and thunderstorms occurring rather than details of where
    that could happen given precipitable water values approaching 1.75
    inches ready to to be lifted isentropically above the front as low
    level flow becomes southerly. The area should become better focused
    in subsequent outlooks.


    Bann
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/1)
  • From Mike Powell@618:250/10 to All on Sat Mar 7 19:01:00 2026
    FOUS30 KWBC 072322
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    622 PM EST Sat Mar 7 2026

    Day 1
    Valid 01Z Sun Mar 08 2026 - 12Z Sun Mar 08 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
    THE CENTRAL GULF COAST...


    Mainly due to convective progression, there has been a significant
    shrinking in both the Marginal and Slight Risk areas. The
    mesoscale guidance most suggests that heavy rain issues from 01z
    onward lie from the Upper TX Coast eastward towards Mobile. The
    degree of moisture, instability, and effective bulk shear available
    near and equatorward of a cold front continues to support the
    potential for hourly rain amounts to 2.5" with local totals to 4".

    While not depicted as a separate Slight Risk, mainly because it's
    out in Brush Country, portions of interior South TX have a chance
    in the very near term for heavy rainfall as well. Although they are
    included in the Marginal Risk category, it's a higher end Marginal
    Risk in that area. Overall, much of the rainfall expected is
    beneficial, relieving long term drought conditions. The intensity
    of organized convection and where storms can train and/or merge
    would threaten urban areas most.

    Roth


    Day 2
    Valid 12Z Sun Mar 08 2026 - 12Z Mon Mar 09 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
    OF THE GULF COAST REGION...

    2100 UTC update:

    No changes made to the previous marginal risk area across the Gulf
    coast region.

    Oravec

    Previous discussion:

    Deep moisture...instability and the risk of excessive rainfall
    should be confined to a shrinking area south of an approaching
    cold front on Sunday. Model guidance showed a corresponding
    decrease in QPF and spaghetti plots from the SREF and the GEFS
    maintaining a few members kept neighborhood probabilities of 1 inch
    or greater confined from Louisiana into Georgia with greatest
    clustering from southern Mississippi into central and southern
    Alabama with QPF spaghetti plots showing few members at 2 inch
    amounts in 24 hours from either the SREF ir GEFS. In this portion
    of the Marginal risk...there was good agreement between WPC and the
    CSU machine learning first-guess ERO. The WPC Marginal Risk area
    extended west along the Louisiana and Upper Texas coast if
    deference to the HREF and RRFS runs which lingered some 1+ in per
    hour rainfall along the coast and even some 2 inch per 6 hour
    lingering through at least 08/18Z. In addition...Gulf moisture
    starts to return northward over southwestern Texas later in the
    period...also supporting a westward expansion.

    Bann


    Day 3
    Valid 12Z Mon Mar 09 2026 - 12Z Tue Mar 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE LOWER MISSISSIPPI VALLEY INTO THE UPPER TENNESSEE VALLEY...

    2100 UTC update:

    Only some minor changes made to the marginal risk area from the
    Lower Mississippi Valley into the Upper Tennessee Valley. Changes
    made were to cover the latest qpf spread for locally heavy precip
    totals day 3 across these regions.

    Oravec

    Previous discussion:

    The front which had been moving from west to east in the Day 1 and
    Day 2 period will slow its forward motion and become oriented along
    a west to east axis on Monday and the start to inch northward
    Monday afternoon and Monday night. There is a wide range of
    solutions in where convection could fire along that boundary which
    limits confidence. However...confidence is higher in the occurrence
    of showers and thunderstorms occurring rather than details of where
    that could happen given precipitable water values approaching 1.75
    inches ready to to be lifted isentropically above the front as low
    level flow becomes southerly. The area should become better focused
    in subsequent outlooks.


    Bann
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Mon Mar 9 08:34:48 2026
    FOUS30 KWBC 090822
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    422 AM EDT Mon Mar 9 2026

    Day 1
    Valid 12Z Mon Mar 09 2026 - 12Z Tue Mar 10 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE LOWER MISSISSIPPI VALLEY & SOUTHEAST...

    Model agreement has started to increase QPF-wise and the present
    Marginal Risk area was adjusted to fit the broad pattern of
    potentially heavy rainfall advertised by the 09/00Z runs of both
    the HREF and REFS guidance. Precipitable water values approaching
    1.75" return somewhat northward as low level flow begins to back
    and accelerate in the lower levels. It appears that enough
    moisture, instability, and effective bulk shear will be present
    near the lower level section of a frontal zone for hourly amounts
    to approach or even exceed 2 inches. Flash flood guidance has
    lowered due to heavy rainfall on Saturday and Saturday night/early
    Sunday morning to partially saturated soils. However, the
    mesoscale guidance signal for 3"+ is low enough at the present time
    to remain in the Marginal Risk category as any flash flooding
    impacts appear no better than isolated to widely scattered.

    Bann


    Day 2
    Valid 12Z Tue Mar 10 2026 - 12Z Wed Mar 11 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE CENTRAL UNITED STATES FROM THE PLAINS TO THE SOUTHERN GREAT LAKES...

    Gulf moisture gets drawn northward over parts of the central U.S.
    from Texas into the Upper Mississippi Valley and southern Great
    Lakes region in response to circulation around an upper level low
    over the Southwest U.S.. This moisture will encounter a southward
    moving cold front from the Upper Midwest and an area of low
    pressure along the front over Kansas or Nebraska on Tuesday. This
    combination should result in convection being capable of producing
    some heavy rainfall rates that results in run off or flooding
    concern across the southern & central Plains and somewhere in the
    neighborhood of the Midwest and/or Ohio Valley. The better
    instability...and higher rainfall rates...look to be over the
    southern part of the outlook area given better instability and due
    to increasingly diffluent flow aloft as the Southwestern U.S. upper
    low approaches. Farther north...the concern for excessive rainfall
    comes from stronger synoptic scale forcing due to the approach of
    an amplifying trough in the northern stream.

    Based on increasing numerical guidance agreement from the
    09/00Z runs...felt confident enough to separate the one Slight
    risk area from yesterday's Day 2 outlook into two Slight risk areas today.

    Some places within each Slight Risk received heavy to excessive
    rainfall in the past few days which has added to soil saturation
    across portions of the Midwest, the Ohio Valley and the Mid-
    Mississippi Valley. Not enough confidence yet to expand the area
    deeper into the Midwest/Ohio Valley due to the lack of any notable mid-
    level capping but the possibility remains.

    Bann


    Day 3
    Valid 12Z Wed Mar 11 2026 - 12Z Thu Mar 12 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE SOUTHERN MISSISSIPPI VALLEY/SOUTHEAST UNITED STATES AND PARTS
    OF THE COASTAL PACIFIC NORTHWEST...

    ...Southern US...
    Maintained a Marginal Risk area over portions of the southern
    states as an upper low propagates eastward on Wednesday. The upper
    level support for heavy rainfall should be waning with time as the
    upper low undergoes slow weakening and filling. Even so...enough
    low level moisture will be in place as mid-level lapse rates
    steepen and increases instability at the time of maximum heating.

    ...Pacific Northwest...
    Persistent on-shore flow of deep moisture into parts of coastal
    Washington and northern Oregon should result in occasional moderate rainfall...mainly in the west face of the coastal ranges. Amounts
    on the order of 2.5 inches to 3.5 inches in 24 hours is forecast
    which could result in isolated flooding ot run off problems in
    areas of poor drainage.

    Bann
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Tue Mar 10 09:13:34 2026
    FOUS30 KWBC 100822
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    422 AM EDT Tue Mar 10 2026

    Day 1
    Valid 12Z Tue Mar 10 2026 - 12Z Wed Mar 11 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE SOUTHERN AND WESTERN PLAINS AND OVER PARTS OF THE SOUTHERN GREAT LAKES...

    The signal for potentially two heavy precip axes persists in the
    guidance..in the very favorable coupled jet entrance/exit regions
    expected between the southern stream closed low moving into the
    Southern Plains and the northern stream jet across Mid Mississippi
    Valley and the Midwest region.

    Gulf moisture gets drawn northward over parts of the central U.S.
    from Texas into the central portion of the Mid-Mississippi Valley
    during the day. There has been a trend in the model guidance over
    the past 24 hours for the core of the higher precipitable water
    values to get shunted more eastward than northeastward...resulting
    in lower model QPF despite the upper support and mid-level
    mesoscale forcing remaining favorable. Consequently...trimmed the
    Slight Risk area to cover only portions of Illinois and Indiana
    where QPF exceeded an inch and which overlapped areas that
    experienced moderate to heavy rainfall a few days ago and have
    suppressed flash flood guidance.

    The better instability...and associated higher rainfall
    rates...still look to be over portions of Texas into southeast of
    Oklahoma as flow aloft becomes increasingly difluent in response to
    an approaching upper low. .Mixed layer CAPE values of 1500 to
    around 2500 J per kg develop ahead of the low where precipitable
    water values will have risen into the 1.25 to 1.5 inch range
    resulting in the potential for 1+ inch per hour rates. The axis of
    model QPF and WPC deterministic QPF align well with modestly-
    lowered flash flood guidance from rainfall several days ago.

    Bann


    Day 2
    Valid 12Z Wed Mar 11 2026 - 12Z Thu Mar 12 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE
    SOUTHERN US...

    The upper low over the southern states will continue to translate
    eastward on Wednesday. The upper support will be weakening as the
    system weakens/fills with time. Model run to run consistency has
    been poor and another round of changes were made this cycle. The
    changes included introduction of a Slight Risk over parts of
    eastern Texas and western Louisiana where model QPF exceeded two
    inches. In addition...there was some overlap between locally heavy
    rainfall a couple of days ago and the QPF.

    ...Pacific Northwest...
    Persistent on-shore flow of deep moisture into parts of coastal
    Washington and northern Oregon should result in occasional moderate rainfall...mainly in the west face of the coastal ranges. Amounts
    on the order of 2.5 inches to 3.5 inches in 24 hours is forecast
    which could result in isolated flooding ot run off problems in
    areas of poor drainage.

    Bann


    Day 3
    Valid 12Z Thu Mar 12 2026 - 12Z Fri Mar 13 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE NORTHWEST UNITED STATES...

    ...Pacific Northwest...
    On-shore flow of deep moisture into parts of coastal Washington
    and northern Oregon persists into the Day 3 period that results in
    occasional moderate to locally heavy rainfall continuing along the
    coastal ranges. An additional 1 to 3 inches in 24 hours are
    possible...which could result in isolated flooding ot run off
    problems in areas of poor drainage.

    Bann
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Wed Mar 11 09:20:27 2026
    FOUS30 KWBC 110827
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    427 AM EDT Wed Mar 11 2026

    Day 1
    Valid 12Z Wed Mar 11 2026 - 12Z Thu Mar 12 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE
    SOUTHERN US...

    As the closed low moves across the central and eastern Texas
    today...an axis of training convection should persist from the
    eastern part of Texas into the lower Mississippi Valley. With very
    strong synoptic forcing and increasing moisture transport we
    should see convection expand in coverage and intensity over eastern
    Texas by mid- to late-morning. During the development phase cell training/backbuilding is probable over east TX, and while
    convection should grow upscale and forward propagate during the
    afternoon, some west to east training is possible near the
    southward dropping cold front. The inherited Slight risk was
    expanded off to the south and east once again to account for model
    trends into parts of Mississippi and western Alabama.

    Only minor nudges were needed to the Marginal risk area across the
    Ohio Valley and into western New York where rainfall rate driven
    localized flash flooding is possible. Areal averaged rainfall is
    only 0.5"-1.5", but given the 500-1000 j/kg and convective nature
    of rainfall, the possibility of localized swaths of rainfall
    exceeding 2 inches persists. This should be enough to at least
    locally exceed FFG across this region. Over western NY, snow melt
    and locally heavy rain may combine to result in areas of excessive runoff.

    Chenard/Bann


    Day 2
    Valid 12Z Thu Mar 12 2026 - 12Z Fri Mar 13 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    Coastal Areas of Washington into Northwest Oregon...

    Only change was to nudge the Marginal risk back to the west just a
    bit given the placement of heavier snowfall in the Cascades.
    Despite that change...much of the shift made by the previous shift
    was retained in this outlook.

    On-shore flow of deep moisture into parts of coastal Washington
    and northern Oregon persists into the Day 2 period...with occasional
    moderate to locally heavy rainfall continuing along the coastal
    ranges. An additional 1 to 3 inches of rainfall in 24 hours is
    possible...which could result in isolated flooding ot run off
    problems in areas of poor drainage.

    Bann


    Day 3
    Valid 12Z Fri Mar 13 2026 - 12Z Sat Mar 14 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    The on-shore flow which has been anchored along coastal portions
    of Washington and northern Oregon will finally start to shift its
    focus southward a bit from Friday into early Saturday morning. The
    axis of a precipitable water plume with values of 0.75 to 1.00
    inches will gradually be shifting southward into Oregon which
    allows precipitation rates to weaken farther north. With the rain
    moving into an area with drier antecedent condition...maintained a
    Marginal Risk area.

    Bann
    $$
    d
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Thu Mar 12 08:47:52 2026
    FOUS30 KWBC 120821
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    421 AM EDT Thu Mar 12 2026

    Day 1
    Valid 12Z Thu Mar 12 2026 - 12Z Fri Mar 13 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    An axis of anomalous PW and 850-700 mb moisture flux
    values...1.5-2.5+ and 2 to 4+ standard deviations above the mean,
    respectively, will continue to impact southern WA state into
    northern Oregon from the Cascades westward to the Coast Ranges.
    Hourly rainfall rates are not expected to be very impressive, at
    most .10-.25"+. However, there is not expected to be a lot of
    movement, overall with this anomalous onshore flow, which will
    support rain for nearly all of the day 1 period in this axis.
    Heaviest precip likely in the upslope of the southern WA Cascades
    and far northern OR Cascades, where HREF and RRFS neighborhood
    probabilities are high for 2 and 3"+ amounts day 1. Changes to the
    previous outlook were to trim the marginal risk southward out of
    coastal southern WA, and through the Willamette Valley to better
    match the latest model qpf consensus.

    Oravec


    Day 2
    Valid 12Z Fri Mar 13 2026 - 12Z Sat Mar 14 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    Not a lot of changes expected overall to the large scale flow
    pattern off the northeast Pacific into portions of the Pacific
    Northwest day 2. The ongoing atmospheric river event will continue
    through much of the day 2 period, with the axis of anomalous PW
    and 850-700 mb moisture flux values...1.5-2.5+ and 2 to 4+
    standard deviations above the mean, respectively, again impacting
    areas from southern WA state into northern Oregon from the Cascades
    westward to the Coast Ranges. Similar to the day 1 period, the
    hourly rainfall rates are not expected to be very impressive, at
    most .10-.25"+. However, there will continue to be little overall
    movement with this anomalous onshore flow axis, which will support
    additional heavy rainfall amounts in the upslope of the northern
    OR/southern WA Cascades and the northern OR Coast Range. Changes to
    the previous outlook were to trim the marginal risk area over
    southern WA and remove it from the Willamette Valley to better
    match the latest model qpf consensus.

    Oravec


    Day 3
    Valid 12Z Sat Mar 14 2026 - 12Z Sun Mar 15 2026

    The probability of rainfall exceeding flash flood guidance values
    is less than 5 percent.

    Oravec
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Fri Mar 13 09:17:07 2026
    FOUS30 KWBC 130745
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    345 AM EDT Fri Mar 13 2026

    Day 1
    Valid 12Z Fri Mar 13 2026 - 12Z Sat Mar 14 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    Final day of impact from a continuous AR regime that has doused the
    Pacific Northwest with several inches of precipitation the last
    72+ hours. Continued fetch off the Pacific will maintain its
    composition for another period with a slow shift south in the
    primary moisture advection regime as the approach of a final, yet
    potent shortwave helps press against the prevailing height field
    situated across the Pacific Northwest into British Columbia. A
    modest 600-800 kg/ms IVT signature has been persistent within a
    zone oriented from Olympia down towards the WA/OR border.
    Expectation is for the IVT advection pattern to pivot south to
    include more of northwest OR extending inland into the southern WA
    and northern OR Cascades leading to an extended moderate
    precipitation band through Friday into early Saturday.

    Current rates are still subject to be focused between 0.25-0.5"/hr
    at peak intensity with perhaps a few localized areas within the
    upslope regions of the Cascades to breach closer to 0.6-0.75/hr at
    times. This alone falls below the FFG criteria for the region,
    however its the longevity and recent priming that would tip the
    scales towards a low-end flash flood scenario, especially within
    the confines of any urbanized zones. Downsloping into the
    Willamette Valley should cause a regional min with this setup
    leading to lower probabilities of any flood concerns in the
    shadowed zone. City of Portland remains right on edge of persistent
    rain bands and waves of moderate rainfall with the heaviest likely
    to focus closer to Astoria and over into the adjacent Cascades
    thanks to the upslope component. D1 QPF indicates the sharp
    delineation in the split maxima with Portland proper right on the
    edge of the higher totals. Considering a solid run-to-run
    continuity across guidance the past 24-36 hours, there wasn't
    really any reason to deviate from the previous MRGL risk
    inheritance as 2-4" of rainfall with local maxima of 6" possible in
    the Cascades are enough to warrant at least a low-end risk.

    Kleebauer


    Day 2
    Valid 12Z Sat Mar 14 2026 - 12Z Sun Mar 15 2026

    The probability of rainfall exceeding flash flood guidance values
    is less than 5 percent.

    Kleebauer


    Day 3
    Valid 12Z Sun Mar 15 2026 - 12Z Mon Mar 16 2026

    The probability of rainfall exceeding flash flood guidance values
    is less than 5 percent.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Fri Mar 13 11:03:21 2026
    FOUS30 KWBC 131550
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    1150 AM EDT Fri Mar 13 2026

    Day 1
    Valid 16Z Fri Mar 13 2026 - 12Z Sat Mar 14 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    THE PACIFIC NORTHWEST...

    16Z Update...

    Generally no change to the previous thinking concerning the long-
    duration atmospheric river impacting the Pacific Northwest.
    However, we did proceed with adding a second Marginal Risk area to
    portions of southeast WA, northeast OR and west-central ID to
    account for heavy rains persisting at some of the lower elevations
    across these areas since the inland core of stronger IVT
    magnitudes continue to impact this region. Antecedent conditions
    across these areas have become increasingly sensitive with the
    rainfall of the past couple days, and given high streamflows, the
    additional rains here may encourage some localized flooding concerns.

    Orrison

    Previous discussion...

    Final day of impact from a continuous AR regime that has doused the
    Pacific Northwest with several inches of precipitation the last
    72+ hours. Continued fetch off the Pacific will maintain its
    composition for another period with a slow shift south in the
    primary moisture advection regime as the approach of a final, yet
    potent shortwave helps press against the prevailing height field
    situated across the Pacific Northwest into British Columbia. A
    modest 600-800 kg/ms IVT signature has been persistent within a
    zone oriented from Olympia down towards the WA/OR border.
    Expectation is for the IVT advection pattern to pivot south to
    include more of northwest OR extending inland into the southern WA
    and northern OR Cascades leading to an extended moderate
    precipitation band through Friday into early Saturday.

    Current rates are still subject to be focused between 0.25-0.5"/hr
    at peak intensity with perhaps a few localized areas within the
    upslope regions of the Cascades to breach closer to 0.6-0.75/hr at
    times. This alone falls below the FFG criteria for the region,
    however its the longevity and recent priming that would tip the
    scales towards a low-end flash flood scenario, especially within
    the confines of any urbanized zones. Downsloping into the
    Willamette Valley should cause a regional min with this setup
    leading to lower probabilities of any flood concerns in the
    shadowed zone. City of Portland remains right on edge of persistent
    rain bands and waves of moderate rainfall with the heaviest likely
    to focus closer to Astoria and over into the adjacent Cascades
    thanks to the upslope component. D1 QPF indicates the sharp
    delineation in the split maxima with Portland proper right on the
    edge of the higher totals. Considering a solid run-to-run
    continuity across guidance the past 24-36 hours, there wasn't
    really any reason to deviate from the previous MRGL risk
    inheritance as 2-4" of rainfall with local maxima of 6" possible in
    the Cascades are enough to warrant at least a low-end risk.

    Kleebauer


    Day 2
    Valid 12Z Sat Mar 14 2026 - 12Z Sun Mar 15 2026

    The probability of rainfall exceeding flash flood guidance values
    is less than 5 percent.

    Kleebauer


    Day 3
    Valid 12Z Sun Mar 15 2026 - 12Z Mon Mar 16 2026

    The probability of rainfall exceeding flash flood guidance values
    is less than 5 percent.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Sun Mar 15 15:11:12 2026
    FOUS30 KWBC 151906
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    306 PM EDT Sun Mar 15 2026

    Day 1
    Valid 16Z Sun Mar 15 2026 - 12Z Mon Mar 16 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    SOUTHEAST PENINSULAR FLORIDA...

    16Z Update...

    The previous forecast remains largely on track based on the latest
    12Z HREF/06Z REFS guidance and recent HRRR solutions which
    continue to depict small-scale clusters of locally heavy showers
    and thunderstorms across the central and southern portions of the
    FL Peninsula. The Marginal Risk for the more sensitive southeast FL
    urban corridor will be maintained.

    Satellite and radar imagery shows convection rapidly developing and
    expanding across portions of the Midwest ahead of the deepening low
    center transiting the region. Very progressive cell-motions are
    still expected to generally keep rainfall totals to a modest level
    at least through this afternoon. There may be some potential for
    some localized cell-training with convection associated with the
    low track this evening across areas of northern IL, northwest IN
    and into southwest Lower MI, but the latest guidance generally
    indicates rainfall amounts through this evening peaking in the 1 to
    2 inch range. The latest FFG exceedance probabilities here are
    very low, and therefore we will continue to hold off on any upgrade
    to a Marginal Risk. However, conditions will be closely monitored
    with today's expected organized convective outbreak. If guidance or satellite/radar trends support heavier short-term QPF, an upgrade
    later today or early this evening could still be necessitated.

    Orrison

    Previous discussion...

    A very strong dynamic cyclone will be in full force across the
    Upper Midwest and Upper Great Lakes with a strong attendant cold
    front crossing out of the Plains through the Lower Ohio and
    Mississippi Valley. The strength of the low level flow prior to the
    cold front will draw modest moisture through the Valleys to provide
    1-1.25" Total PWat values. The focus will be on severe aspects of
    the convective line and there will be some stronger updrafts and
    solid moisture flux convergence associated with these convective
    cores capable of sub-hourly to hourly rates/totals in the vicinity
    of 1-1.5"; the duration will be brief to limit overall totals to
    less than 2" overall. This could result in random, widely spaced
    incident or two of flash flooding, but limited to urban and
    traditionally flood prone locations. So while there is a non-zero
    risk of excessive rainfall, it remains below the 5% coverage for a
    Marginal Risk to be delineated at this time but will continue to
    monitor trends for subsequent updates.

    Further southeast, the draw of moisture out of the Caribbean
    through the Strait of Yucatan will draw higher moisture though the
    eastern Gulf. Combined with return easterly flow north of the
    Greater Antilles into the Bahamas; there is an increase in
    moisture confluence (total PWats to 1.75") through Peninsular
    Florida. Onshore flow from the southeast and clearing skies will
    allow for some increased instability (1250-1500 J/kg) to build for
    thunderstorm activity across the southern Peninsula before evening.
    Rates in excess of 2"/hr may result in highly localized spots of
    2-5" that may result in localized rapid inundation flooding if over
    the southern I-95 urban corridor. Converging sea-breezes may also
    result in mergers across the central Peninsula from north to south,
    but are likely to be more intense initially but also much more
    brief relative to those closer to coastal convergence zones that
    may allow for longer duration. HREF probabilities of 3-5"/24hrs are
    sufficient to highlight a small Marginal Risk of Excessive
    Rainfall.

    Gallina


    Day 2
    Valid 12Z Mon Mar 16 2026 - 12Z Tue Mar 17 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID-ATLANTIC AND NORTHEASTERN U.S & EXTREME NORTHWEST WASHINGTON...

    19z Update: Forecast looks on track. Nothing in the 12z high res
    guidance supports any changes to the inherited Marginal risk areas.

    Chenard

    ...Mid-Atlantic into Northeast...
    Highly meridional moisture surge will be already ongoing at the
    start of the forecast period (16.12z) as the leading edge of the
    Atlantic warm front should be lifting through southern New England
    and Gulf of Maine. Upstream the highly dynamic cyclone will be well
    occluded through depth across the north-central Great Lakes with a
    powerful near 980mb surface low and attendant sharp cold front
    extending due south across the Mid-Ohio Valley, Cumberland Plateau
    into the central Deep South. The based of the large scale trough
    will be lifting northeastward providing solid dPVA to support
    strengthening deep layer southerly flow further compounding on the
    initial warm advective surge through out of the Southeast through
    the Mid-Atlantic. Integrated Vapor Transport (IVT) values will
    increase from upper hundreds of kg/m/s toward 1250 kg/m/s across
    the Coastal Plain into southern New England eventually reaching
    values over 1400 kg/m/s after 00z through S ME due to the combining
    strength of the LLJ and confluent moisture streams off the Eastern
    Gulf and Western Atlantic. This brings moisture flux well above
    97-99th+ percentiles of moisture flux. Instability will be a
    limiting factor for vertical development along/ahead of the cold
    front but some 250-750 J/kg will be available through the central
    Mid- Atlantic with some localized convergence for scattered showers
    and thunderstorms prior to the main cold front/squall line to
    emerge out of the Appalachian terrain by mid-day. These initial
    cells should be quick moving and limited in total, but any that
    broaden into stronger isolated super-cells may have capability for
    locally intense rates prior to the main line. Still, the main focus
    will be the hourly to sub- hourly 1-1.5+" totals with the main
    convective line that will have greatest potential for localized,
    mainly minor flash flooding impacts.

    Hydrologically, the Northeast remains highly saturated and cold
    through depth with modest SWE in some remaining snow pack. So,
    while the rain rates will likely be much lower due to lack of deep unstable/vertical shower activity; the orographic ascent and should
    remain concerning that any rain on snow will further compound the
    ongoing hydrologic/stream rises (please refer to National Water
    Center FHO and Local River Forecast Center forecasts for further
    river concerns across this region).

    As such a broad Marginal Risk will remain in place for nearly all
    of the Northeast (minus areas in south to south-southwest rain
    shadow areas of far N VT), with an extension of the Marginal into
    the Potomac River Valley and southern extents of the Megalopolis
    where those higher rates/short-burst totals may result with
    localized exceedance of lower hourly FFG values.

    ...Pacific Northwest...
    Prolonged warm advection of a moderate positively anomalous
    moisture stream will be continuing across the extreme northwestern
    portion of the Olympic Peninsula with a very weak continuation to
    the northern Washington Cascades. Rates will remain fairly
    consistent between .25"-.33"/hr allowing for totals to near 3-5"
    toward the the end of the forecast period with 00z HREF probability
    of 5" nearing 30%; though 5"/24hr just across the Sound will be
    near 60%. By late evening/early overnight period, the cold front
    will be starting to surge southeastward and further direct enhanced
    moisture flux toward the Olympic Peninsula after 06z, with 1-1.25"
    Total PWats fluxed on 40-45kts of flow generally resulting in about
    750 kg/m/s IVT values, bringing rates locally up to .5" for the
    best orographic ascent regions. As such, a very small Marginal Risk
    was included for this AR surge into an area already at above
    average soil saturation due to recent AR plumes in the last few
    days/week(s).

    Gallina


    Day 3
    Valid 12Z Tue Mar 17 2026 - 12Z Wed Mar 18 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    NORTHWEST WASHINGTON...

    19z Update: Marginal risk looks on track, thus no changes needed.

    Chenard

    At the start of the day 3 forecast period, 18.12z, the strong,
    prolonged Atmospheric River had recently shifted slightly eastward
    directing the core of the AR plume centered across Northwest
    Washington into the northern Cascades, oriented from SW to NE. Deep
    layer moisture remained well above normal with total PWat values
    remaining well above 1" with 1.25" reaching the southwest flanks of
    the Olympic Range. Winds had calmed a tad but remain around or
    above 40kts through the 850-700mb range favorably orthogonal to the
    Olympic Range. Freezing levels are well above even the highest
    peaks, exposing some Snow Water Equivalent (SWE) to the higher WAA southwesterly flow adding to the .25"-.33"/hr rain rates though
    will be higher earlier in the period as winds slack ever so subtly
    between shortwave features. Overall IVT values will remain above
    500 kg/m/s with peak values over 750 that extend into the northern
    Cascades as well. As such, 24hr totals will once again be over 3-4"
    and combined with the snow melt, could further increase stream
    flows. With lower rates, a Marginal Risk of Excessive Rainfall will
    remain in place; however, please refer the National Water Center
    and NWRFC forecasts for stream/river flow/rise information with
    respect to increasing flooding potential.

    Gallina
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Mon Mar 16 09:15:32 2026
    FOUS30 KWBC 160730
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    330 AM EDT Mon Mar 16 2026

    Day 1
    Valid 12Z Mon Mar 16 2026 - 12Z Tue Mar 17 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MID-ATLANTIC AND NORTHEASTERN U.S...

    Broad axis of diffluence positioned over the Ohio Valley into the
    Northeast will lead to multiple rounds of convection once east of
    the Appalachian front. Warm moist air will continue to funnel
    poleward ahead of a very amplified trough axis centered over the
    Midwest to Mid-Mississippi Valley. PWATs across the Mid Atlantic
    have already surged beyond 1", a solid 3 standard deviations above
    normal compared to climatology putting into the 97-99th percentile
    for mid-March. Expectation is for this surge to continue pushing
    further north within the amplified flow east of the Mississippi
    leading to a large swath of the east coast to exhibit an
    environment favorable for at least the threat of heavy rainfall.

    A multi-round scenario of convective impacts are anticipated as
    weak mid-level perturbations usher north-northeast ahead of the
    mean trough and cold front migrating through the Ohio Valley. Prior
    to the cold front arrival and associated precip field along and
    ahead of the front, moderate to locally heavy rains from
    convective clusters could help prime local soils before the main
    time frame of impact after 18z occurs. One of the trends within
    guidance was a relatively skinny convective segment that will be
    the main player in the higher rates exhibited in this setup. The
    linear segment will be relatively progressive, but rates between
    0.75-1.5"/hr at peak intensity are plausible as it moves through
    the Mid Atlantic and Northeast leading to a threat for flash
    flooding as it migrates into the Piedmont and urban zones
    characterized within the Northeastern Megalopolis. Areal average
    of 0.75-1.5" is forecast for much of the area from northern VA up
    into NY state and Northeast New England. The maxima of over 2" is
    still showing up within deterministic output via both global and
    CAMs physics. The area of interest continues to point to
    CT/RI/Southern MA as the primary spot for more appreciable totals
    2". This is supported via the neighborhood prob fields of 50-80%
    for at least 2" by the latest 00 HREF output. Other notable areas
    include high probs >70% for at least 1" aligned along the Blue
    Ridge to the I-95 corridor for VA/MD/PA extending into the Lower
    Hudson and Catskills area of NY state. Another axis of higher probs
    exists across eastern ME and parts of Northern New England which
    coupled with high SWE presence should allow for rapid snow melt and
    potential for local hydrologic issues stemming from both the
    precip and snow/ice melt. This signal was sufficient for
    maintenance of the previous MRGL risk with only some minor
    adjustments on the southern edge of the risk area to account for
    the latest model trends.

    The progressive nature of the precip should curb some of the flash
    flood concerns making this a solid MRGL risk with perhaps a bump in
    the risk magnitude if guidances trends more aggressive in QPF
    output. For now, this is a classic setup for early spring
    convection and modest flash flood prospects.

    Kleebauer


    Day 2
    Valid 12Z Tue Mar 17 2026 - 12Z Wed Mar 18 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Active pattern across the Gulf of Alaska will lead to another AR
    contribution into portions of the Pacific Northwest as the main
    IVT surge will adjust south into WA state after impacting
    neighboring British Columbia the day prior. Looking at IVT values
    between 500-700 kg/ms across northwest WA state with the surge
    propagating far enough inland to impact the Northern Cascades.
    Rainfall amounts between 2-3" will be common in the hardest hit
    areas, mainly into the Olympic Peninsula, Chehalis River valley,
    as well as the Cascades to the east of Seattle. Rates will lack
    vigor to the point for a more substantial impact, so the threat is
    mainly due to prolonged moderate to locally heavy rain prospects
    falling over relatively moist soil layer present after being
    impacted for weeks leading in. The previous MRGL risk was generally
    unchanged with the threat leaning towards the lower-end of the risk
    threshold. Areal hydrologic concerns are still viable with river
    and small stream flooding the most notable potential impacts.

    Kleebauer


    Day 3
    Valid 12Z Wed Mar 18 2026 - 12Z Thu Mar 19 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Occluded low over the Gulf of Alaska a strong mid-level ridge
    positioned across the Southwest U.S. will lead to a continued
    transport of modest IVT into WA state for the D3 period. AR
    dominated pattern will enhance rainfall prospects for the northern
    half of WA leading to cumulative rainfall totals breaching 4" in
    spots within the Northern Cascades, Olympics, and adjacent coastal
    areas of northwest WA. Real concern is the growing hydrologic
    factors with river flooding coupled with moderate rainfall posing a
    problem for areas around the main rivers and tributaries for the
    aforementioned areas. Flash flood threat remains low due to the
    rates anticipated with the rainfall as hourly rainfall will remain
    <0.5"/hr for a majority of Wednesday. However, the coupling of the
    previous days rain and the already saturated soils will likely lead
    to some hydro concerns mid-week, so maintained the previous MRGL
    risk inherited with only some minor tweaks at the southwest edge of the risk.


    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Tue Mar 17 08:58:11 2026
    FOUS30 KWBC 170741
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    341 AM EDT Tue Mar 17 2026

    Day 1
    Valid 12Z Tue Mar 17 2026 - 12Z Wed Mar 18 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Active pattern across the Gulf of Alaska will lead to another AR
    contribution into portions of the Pacific Northwest as the main
    IVT surge will adjust south into WA state after impacting
    neighboring British Columbia the past 24-48 hours. IVT forecast
    remains consistent within guidance as values between 500-700 kg/ms
    are expected across northwest WA state with the surge propagating
    far enough inland to impact the Northern Cascades. Rainfall amounts
    between 2-3" will be common in the hardest hit areas, mainly into
    the Olympic Peninsula, Chehalis River valley, as well as the
    Cascades to the east of Seattle. Latest 00z HREF neighborhood
    probabilities for >2" of rainfall over the course D1 are running
    between 50-70% across the Olympic Peninsula into the Chehalis River
    basin where Flood Watches have been issued for the upcoming AR.

    Probabilities for the Northern Cascades are more robust for the
    same 2" threshold, running between 70-90+% across the entire area
    from Mount Rainier up to the Canadian border. Greater than 3"
    probs are modest between 50-70% in those interior terrain areas,
    including the highest elevations of the Olympics. Snow levels are
    forecast to be around 8000ft MSL leading to a large portion of the
    mountain ranges to see ample rainfall and snow melt that will
    contribute to higher run off prospects. Rainfall rates will lack
    vigor to the point for a more substantial impact, so the threat is
    mainly due to prolonged moderate to locally heavy rain prospects
    falling over relatively moist soil layer present after being
    impacted for weeks leading in coupled with the expected snow melt.
    The previous MRGL risk was generally unchanged with the threat
    leaning towards the low to mid level of the risk threshold. Areal
    hydrologic concerns are still viable with river and small stream
    flooding the most notable potential impacts as forecasts around
    some of the major river basins, including the Chehalis River, are
    expected to reach into Action stage and even some minor river flood forecasts.

    Be sure to check into the latest forecasts from the local Seattle
    WFO and the National Water Center for the latest on the river
    flooding threat.

    Kleebauer


    Day 2
    Valid 12Z Wed Mar 18 2026 - 12Z Thu Mar 19 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Occluded low over the Gulf of Alaska and a strong mid-level ridge
    positioned across the Southwest U.S. will lead to a continued
    transport of modest IVT into WA state for the D2 period. AR
    dominated pattern will enhance rainfall prospects for the northern
    half of WA leading to cumulative rainfall totals breaching 4" in
    spots within the Northern Cascades, Olympics, and adjacent coastal
    areas of northwest WA. Real concern is the growing hydrologic
    factors with river flooding coupled with moderate rainfall posing a
    problem for areas around the main rivers and tributaries for the
    aforementioned areas. Flash flood threat remains lower end by
    definition due to the rates anticipated with the rainfall as
    hourly rainfall will remain <0.5"/hr for a majority of Wednesday.
    However, the coupling of the previous days rain and the already
    saturated soils will likely lead to some hydro concerns mid-week,
    especially for the Chehalis River basin and the rivers/stream
    connected with the Northern Cascades as they encounter the tandem
    of rainfall and snow melt. Maintained the previous MRGL risk
    inherited with no modifications necessary as the forecast remains on track.

    Kleebauer


    Day 3
    Valid 12Z Thu Mar 19 2026 - 12Z Fri Mar 20 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Persistent onshore flow within a zone focused between a broad
    occluded cyclone in the Gulf of Alaska and a stout ridge axis
    focused over the Southwestern U.S. will lead to a prevailing
    moderate rain setup over much of the same areas impacted the
    previous periods. Total rainfall in the Northern Cascades over into
    the Olympic Peninsula will run between 4-7" with local amounts to
    9" possible in the 72 hour time frame of the AR. The same impact
    scenarios apply with the focus being a compounding factor of
    rainfall, snow melt, and prolonged run off into local rivers and
    streams that could result in flooding prospects for multiple days
    as river levels reach action stage and minor to even moderate flood
    stages. It will be important to maintain awareness on local river
    conditions as the additional rain will exacerbate any receding
    potential within the river basins. Highest impacted zone will
    continue to be the Chehalis River basin where Flood Watches are in
    effect for multiple days due to the prolonged AR and river levels
    continue to run high after several weeks of rainfall. Additional
    watches are in effect over the Northern Cascades due to anticipated
    run off from rain and snow melt leading to newer hydro concerns as
    the event wears on.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Wed Mar 18 09:26:38 2026
    FOUS30 KWBC 180739
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    339 AM EDT Wed Mar 18 2026

    Day 1
    Valid 12Z Wed Mar 18 2026 - 12Z Thu Mar 19 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Persistent AR across WA state will lead to bouts of moderate to
    occasionally heavy rainfall across the Olympic Peninsula into the
    Northern Cascades. Down-sloping will reflect a general min across
    the Seattle area, but the terrain will be susceptible to ongoing
    rain prospects and totals between 1-3" for the day. This is an ongoing
    threat that will carry on beyond the period adding a compounding
    factor to the hydrologic responses anticipated across the River
    basins within northwest WA. High snow levels ~8000ft MSL will lead
    to snow melt across the higher elevations within the Northern
    Cascades and Olympic Mountain ranges to couple with the rainfall.
    This excessive run off will be another factor in the additional
    water sources that will drain into nearby streams and rivers that
    will induce at least several action stage responses and some minor
    to borderline moderate river flooding across the region. The
    primary river of impact will continue to be the Chehalis River
    where minor flooding is already occurring and additional elevated
    stream flows and run off entering into the tributaries will
    eventually cause the crests of the river to slowly rise. Flood
    Watches are in effect across portions of northwest WA state,
    including Mason county where the greatest focus of flooding will
    occur around the Chehalis River. Considering the hydrologic factors
    at play despite rates only topping out around 0.5"/hr at peak
    intensity, a MRGL risk was carried over for the period with little
    to no change from the previous risk issuance.

    Kleebauer


    Day 2
    Valid 12Z Thu Mar 19 2026 - 12Z Fri Mar 20 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    There are no changes from the prior forecast as the overall synoptic
    pattern remains consistent in run-to-run continuity. Prevailing
    onshore flow within a zone focused between a broad occluded cyclone
    in the Gulf of Alaska and a stout ridge axis focused over the
    Southwestern U.S. will lead to a prevailing moderate rain setup over
    much of the same areas impacted the previous periods. Total rainfall
    in the Northern Cascades over into the Olympic Peninsula will run
    between 4-7" with local amounts to 9" possible in the 72 hour time
    frame of the AR. The same impact scenarios apply with the focus
    being a compounding factor of rainfall, snow melt, and prolonged run
    off into local rivers and streams that could result in flooding
    prospects for multiple days as river levels reach action stage and
    minor to even moderate flood stages. It will be important to
    maintain awareness on local river conditions as the additional rain
    will exacerbate any receding potential within the river basins.
    Highest impacted zone will continue to be the Chehalis River basin
    where Flood Watches are in effect even into D3 (see below) due to
    the prolonged AR and river levels continuing to run high after
    several weeks of rainfall. Additional watches are in effect over the
    Northern Cascades due to anticipated run off from rain and snow melt
    leading to newer hydro concerns as the event wears on. The previous
    MRGL risk inherited was unchanged given the continuity.

    Kleebauer


    Day 3
    Valid 12Z Fri Mar 20 2026 - 12Z Sat Mar 21 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WASHINGTON STATE...

    Final day of impact for the current AR event over WA state will
    occur within the D3 period with much of any rainfall expected to occur
    in the first half Friday before the event finally comes to a close
    a strong shortwave trough exits the Pacific with a cold front
    passage signaling the end to the threat. Additional 1-2 inches of
    rainfall across northwest WA will bring final event totals to the
    5-10 inch range over the span of 4 days which will ultimately
    contribute to persistent river flood concerns thanks to the snow
    melt coupled with rainfall to drain into the basins surrounding the
    Olympic Peninsula and Northern Cascades. The last wave of precip
    will be relatively heavy compared to the prior period as the
    shortwave addition will add a bit more vigor in the ascent pattern
    along with IVT and PWAT advection anomalies pushing 3-4 standard
    deviations above normal, respectively. Thankfully, this last push
    will materialize and end fairly quickly as the fast flow provided
    by a stout 165kt upper jet max will advance the final
    wave/disturbance eastward into southern British Columbia dragging
    the cold front swiftly through the region between 18-00z Fri/Sat.
    Flood Watches for the Cascades and portions of the Olympic
    Peninsula, with a focus on the Chehalis River remain in effect
    until Friday afternoon local time. The previous MRGL risk was
    generally unchanged as the pattern remains locked-in across various
    guidance.

    Kleebauer
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Thu Mar 19 08:13:01 2026
    FOUS30 KWBC 190700
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    300 AM EDT Thu Mar 19 2026

    Day 1
    Valid 12Z Thu Mar 19 2026 - 12Z Fri Mar 20 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WESTERN WASHINGTON STATE...

    An atmospheric river of moisture and rainfall originating from the
    tropics near Hawaii (a.k.a. Pineapple Express) will be directed at
    the Olympics and Cascades of western Washington State on Thursday.
    The plume will be guided by a large and very anomalously strong
    upper level high/ridge over the Southwest, and a series of lows,
    both over the Pacific and the Gulf of Alaska. The plume itself will
    be anomalous in that the moisture content will be between 3 and 4
    sigma above normal for March for western Washington as PWATs exceed an inch.

    Heavy rain will impact much of western Washington through the day
    on Thursday. A brief diminishing of the rain is expected through
    the first half of Thursday night before a weak wave of low pressure
    moves into southern British Columbia, and another round of heavier
    rain moves in after midnight. Total rainfall amounts will be in the
    2-4 inch range in the Olympics and northern Cascades. This rain
    will be on top of already saturated soils from prior rain events,
    so much of the new rainfall will quickly convert to runoff.
    Isolated flash flooding is probable, especially in urban and
    flood-prone areas.

    Wegman


    Day 2
    Valid 12Z Fri Mar 20 2026 - 12Z Sat Mar 21 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WESTERN WASHINGTON STATE...

    A weak wave of low pressure will move ashore into Vancouver Island
    very early Friday morning. The moisture associated with its
    trailing front will continue the heavy rain into western Washington
    from overnight Thursday night. The low will dissipate in southern
    British Columbia during the day Thursday, but the associated
    rainfall will likely continue for much of the day Friday. Once the
    center of the low reforms over the Plains in Alberta, the flow will
    weaken enough to end any upslope into western Washington, and
    ending the rainfall event. Nevertheless, expect an additional 1-2
    inches of rain into the Olympics and another 2-3 inches into the
    Washington Cascades before the rain ends. Given plentiful earlier
    rains from Day 1/Thursday, there is some potential for flooding to
    be ongoing at the start of the period. In which case, additional
    rainfall could worsen ongoing flooding and/or initiate new
    flooding. A Slight Risk upgrade could be needed with future updates
    in the northern Cascades.

    Wegman


    Day 3
    Valid 12Z Sat Mar 21 2026 - 12Z Sun Mar 22 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Fri Mar 20 09:02:58 2026
    FOUS30 KWBC 200718
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    318 AM EDT Fri Mar 20 2026

    Day 1
    Valid 12Z Fri Mar 20 2026 - 12Z Sat Mar 21 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    WESTERN WASHINGTON STATE...

    At the beginning of the forecast period, a stubborn atmospheric
    river is forecast to weaken as a surface low and attendant cold
    front progress eastward into the Pacific Northwest. Even so,
    moderate IVT values on the order of 500-700 kg/m * s directed into
    the WA coastline from 12-18Z should maintain the threat of locally
    heavy rainfall ahead of the front. While hourly rainfall rates will
    likely remain below 0.5 inches per hour, isolated instances of
    excessive rainfall remain possible in upslope regions of the
    Olympics and Cascades owing to antecedent rainfall over the last few days.

    Asherman


    Day 2
    Valid 12Z Sat Mar 21 2026 - 12Z Sun Mar 22 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Asherman


    Day 3
    Valid 12Z Sun Mar 22 2026 - 12Z Mon Mar 23 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Asherman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Sun Mar 22 09:42:42 2026
    FOUS30 KWBC 220804
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    404 AM EDT Sun Mar 22 2026

    Day 1
    Valid 12Z Sun Mar 22 2026 - 12Z Mon Mar 23 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE UPPER
    OHIO VALLEY TO THE NEW YORK CITY METRO...

    A strong cold front, supported by a passing upper level shortwave,
    will press southward from the Great Lakes towards the upper Ohio
    Valley and the mid-Atlantic. The warm air mass ahead of the front
    is characterized by dew points in the lower 60s across the Ohio
    Valley and upper 50s across the mid-Atlantic. These are hardly
    great amounts of moisture. Nonetheless, especially over the Ohio
    Valley, instability will increase Sunday afternoon to between 1,000
    and 2,000 J/kg. This will be enough to support widespread
    thunderstorm development ahead of the front. The flow of warm air
    will be out of the WSW, essentially parallel to the front. This
    will support cells within the SSE-ward moving line moving east,
    allowing for some opportunity for some training. The combination of
    better upper level support from the aforementioned shortwave,
    greater instability, and available moisture will begin to counter
    the much drier-than-normal soils and rather fast movement of the
    cold front. Organized convection will break out across Pennsylvania
    in the late afternoon, then "zip" southwestward across the upper
    Ohio Valley during the evening, with storms persisting well into
    the overnight hours. The inherited Marginal Risk area was expanded
    south and west to include more of southeast Ohio and northern West
    Virginia, where the threat for training storms could result in
    isolated instances of flash flooding.

    Further east, across much of Pennsylvania, wetter-than-normal
    soils from recent rains could support enough rainfall from storms
    to result in isolated instances of flash flooding. East of the
    Appalachians, however, instability rapidly decreases the closer to
    the ocean you go. This will result in decreasing rainfall rates for
    any storms that move east off the mountains. The front will also
    be slower to move south than the same front further east. Thus,
    while any rain rates from mostly stratiform precipitation will be
    low, a longer period of time of rain along with wetter soils could
    also prove enough to result in isolated flash flooding. The
    inherited Marginal Risk from central Pennsylvania east to the New
    York City Metro is unchanged from inherited.

    Wegman


    Day 2
    Valid 12Z Mon Mar 23 2026 - 12Z Tue Mar 24 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman


    Day 3
    Valid 12Z Tue Mar 24 2026 - 12Z Wed Mar 25 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Portions of western Washington State, specifically the Olympic and
    Cascades Mountains, will be monitored for a potential Marginal
    Risk introduction with future updates. A front moving into the area
    will make for a brief time (12-hour) of heavy rain Tuesday morning.
    While this would normally not be nearly long enough to result in
    flash flooding, given there is ongoing river flooding from the last
    event, and both soils and streams/creeks are full, this round of
    heavy rain may be enough to cause renewed isolated flash flooding.

    Wegman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Mon Mar 23 08:08:51 2026
    FOUS30 KWBC 230600
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    200 AM EDT Mon Mar 23 2026

    Day 1
    Valid 12Z Mon Mar 23 2026 - 12Z Tue Mar 24 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman


    Day 2
    Valid 12Z Tue Mar 24 2026 - 12Z Wed Mar 25 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    ...Western Washington State...

    Guidance on rainfall amounts with a brief round of heavy rain
    Tuesday has not changed appreciably. Low snow levels will allow
    much of the expected precipitation to fall as snow. Thus, the area
    will be monitored but no Marginal Risk is needed.

    ...Northeast Florida...

    A nearly stationary low off the coast of St. Augustine/Daytona
    Beach may support nearly stationary convection forming over/near
    I-95 in that area. Any storms that form will be capable of
    producing heavy rain. Very dry soils and generally flat, flood-
    averse drainage basins are likely to be able to absorb any heavy
    rain. The area will continue to be monitored for an eventual
    Marginal Risk as stationary storms over a semi-urban area for an
    extended period could result in localized flooding/ponding.

    Wegman


    Day 3
    Valid 12Z Wed Mar 25 2026 - 12Z Thu Mar 26 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)
  • From Mike Powell@618:250/10 to All on Tue Mar 24 08:53:22 2026
    FOUS30 KWBC 240622
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    222 AM EDT Tue Mar 24 2026

    Day 1
    Valid 12Z Tue Mar 24 2026 - 12Z Wed Mar 25 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman


    Day 2
    Valid 12Z Wed Mar 25 2026 - 12Z Thu Mar 26 2026

    The probability of rainfall exceeding flash flood guidance is less
    than 5 percent.

    Wegman


    Day 3
    Valid 12Z Thu Mar 26 2026 - 12Z Fri Mar 27 2026

    ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
    THE MIDWEST AND OHIO VALLEY...

    A strong cold front will move southward across the Midwest Thursday
    night. The front will run into a marginally unstable and warm air
    mass, but with limited moisture with surface dew points on either
    side of 60 degrees. Nonetheless, with some upper level support and
    significant shear, organized thunderstorms are likely to form
    Thursday evening. The storms could then train over many of the
    same areas that saw some heavy rain from a very similar-behaving
    front yesterday. This is a lower-end Marginal Risk as upper level
    support and instability will both not be quite as favorable to the
    storms as yesterday. This will be somewhat offset by a bit wetter
    soils by then than they were before yesterday's rainfall event. The
    areas most likely to see an instance or two of flash flooding are
    the urban centers. Should forecast rainfall decrease, which appears
    possible, the Marginal may be able to be dropped with future
    updates.


    Wegman
    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (618:250/10)