• HVYRAIN: Excessive Rainfall D3-5

    From Mike Powell@618:250/10 to All on Sat Jul 18 09:57:50 2026
    FOUS30 KWBC 180834
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    434 AM EDT Sat Jul 18 2026

    Day 3 Valid 12Z Mon Jul 20 2026 - 12Z Tue Jul 21 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
    ARIZONA AND NEW MEXICO...

    ...Southwest...
    The primary adjustment for this forecast cycle is the introduction
    of a Slight Risk across portions of New Mexico and Arizona. For
    parts of the region, the setup remains much the same, with
    anomalous moisture (2+ std dev above normal) supporting convective
    activity and rainfall efficiency.

    Mid-to-upper level energy/an inverted trough drifting east across
    the region will provide larger-scale ascent to help better
    organize monsoon convection. Furthermore, this feature will help
    steer and push the convective and heavy rainfall threat a bit
    farther west across portions of southeastern Arizona than in the
    previous days. Given the combination of persistent anomalous
    moisture, enhanced upper-level support, and sensitive soils,
    expect localized rainfall rates to easily raise runoff concerns
    across parts of the region. A surrounding broad Marginal Risk
    remains in place extending up into the Great Basin and central
    Rockies -- outlining the risk for less-organized storms, producing
    isolated runoff concerns in those area.

    ...Upper Great Lakes...
    A well-defined shortwave interacting with deepening moisture is
    expected to produce strong storms capable of producing heavy
    rainfall across the region. Guidance shows southwesterly to
    easterly inflow supporting PWs increasing to around 2 inches. This
    moisture along with strong ascent, afforded in part by favorable
    upper jet dynamics, will fuel the potential for heavy rainfall-
    producing storms. Training storms along the front may raise the
    threat for heavy amounts and flash flooding concerns. Models differ
    on the details, but there is some consensus for the heaviest
    amounts centering from southern Wisconsin to northern Illinois,
    where an upgrade to a Slight may be introduced in a future
    issuance, if the trends hold.

    ...Eastern North Carolina...
    A Marginal Risk was maintained where a front and coinciding pool of
    deep moisture (PWs at or above 2 inches) are expected to linger,
    extending the threat for heavy rainfall and possible flash flooding
    into a second day.

    ...Florida Gulf Coast...
    It remains uncertain how the disturbance in the eastern Gulf will
    evolve and track. However, regardless of development, it is
    expected that heavy rainfall will remain a threat for parts of the
    Gulf Coast. Therefore, a Marginal Risk was maintained from the
    Tampa Bay region to the Panhandle.

    Pereira


    Day 4 and Day 5 Valid 12Z Tue Jul 21 2026 - 12Z Thu Jul 23 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    SOUTHWEST AS WELL AS THE CENTRAL APPALACHIANS ON TUESDAY...

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR EASTERN NORTH
    CAROLINA AND SOUTHEASTERN VIRGINIA ON WEDNESDAY...

    ...Southwest...

    The Southwest Monsoon will remain in full force across Arizona and
    into Utah on Tuesday. Moisture anomalies especially to the north
    across Utah could approach 5 sigma above normal for this time of
    year, while into Arizona, PWATs to 2 inches will be a solid 3 sigma
    above normal. With daytime heating, renewed rounds of thunderstorms
    are expected to redevelop for the latest in the multi-afternoon
    pattern. Soil moisture levels are already saturated over much of
    Arizona and into southern Utah. Expect with the thermal low peaking
    in intensity on Tuesday, that flash flooding concerns will become
    more widespread as rains impact beyond the 4 Corners into Nevada,
    Idaho, and Wyoming. A Slight Risk upgrade was introduced with this
    update, and it's possible localized areas may see further upgrades
    as Tuesday approaches. By Wednesday, ridging over the Southwest
    will push the greater threats for thunderstorms further north into
    the Intermountain West, with a low developing over the Plains
    allowing for some of the moisture to overspread into portions of
    the central Plains. The signal for heavy rain lessens on Wednesday,
    so the threat drops to Marginal for now, though a Slight may be
    needed into the Intermountain West with continued consistency in
    the guidance.

    ...Central Appalachians...

    A Slight Risk upgrade was also introduced for portions of the
    Central Appalachians, particularly across West Virginia and into
    southwest Pennsylvania. Abundant moisture across the Mid-Atlantic
    will interact with a strong cold front pushing southwest across
    Ohio during the afternoon. This will allow for numerous
    thunderstorms to develop Tuesday afternoon. Upslope flow into the
    flash flood prone mountains of West Virginia and Pennsylvania will
    support additional thunderstorm development as compared with areas
    further west where the front will clear the moisture, and further
    east where there will be less forcing. PWATs approaching 2 inches
    will also support storms capable of multiple inch per hour rainfall
    rates, especially as they run into the mountains.

    To the east across the Mid-Atlantic, moisture levels further
    increase, with some areas perhaps reaching 2.25 inch PWATs Tuesday
    afternoon. The forcing will be a bit more uncertain, but any storms
    that form will be capable of very heavy rains. The I-95 corridor
    from DC to NYC will have to be closely monitored as these heavily
    populated and flood prone areas may have enough widespread activity
    to need further upgrades.

    ...Tidewater of North Carolina and Virginia...

    On Day 5/Wednesday, the same cold front that swings through the
    Midwest, Northeast, and Mid-Atlantic on Tuesday slows down its
    forward speed, perhaps even stalling to the west of the Tidewater
    of North Carolina and Virginia. Plentiful tropical moisture
    continues riding northeastward along that front, providing ample
    opportunity for numerous training showers and thunderstorms to
    develop over the region, likely moving out over the Atlantic off
    Ocean City, Maryland and points north. Thus, the focus will be in
    the highly urbanized Hampton Roads area, extending into much of the
    coastal plain of North Carolina. Given the pretty impressive signal
    for heavy rain, have started out the Day 5 ERO with a Slight Risk
    in this region. There remains some uncertainty as to whether any
    tropical development over the northeastern Gulf contributes to the
    heavy rainfall expected in this region on Wednesday. Given the
    signals for heavy rain expected Sunday/Monday over eastern North
    Carolina, expect the soils by Wednesday to be significantly more
    saturated than they are now, contributing to the heightened flash
    flooding risk.

    Wegman
    $$
    --- MultiMail/DOS
    * Origin: capitolcityonline.net * KY, USA (618:250/10)
  • From Mike Powell@618:250/10 to All on Sun Jul 19 09:01:08 2026
    FOUS30 KWBC 190921
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    521 AM EDT Sun Jul 19 2026

    Day 3 Valid 12Z Tue Jul 21 2026 - 12Z Wed Jul 22 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    SOUTHWEST, CENTRAL APPALACHIANS, OHIO VALLEY, AND THE MID ATLANTIC COAST...

    ...Southwest to the northern Rockies...
    Models show the upper high continuing to shift east as an upper
    trough begins to drift into the Pacific Northwest. This will allow
    the monsoon moisture plume to spread further north, with moisture
    anomalies over 3 std dev above normal extending as far north as the
    northern Rockies. This will support increasing convective
    development with isolated flash flooding concerns as far north as
    southwestern Montana and southern Idaho.

    However, the greater heavy rainfall and flash flooding threat is
    expected to remain centered over western New Mexico, Arizona, and
    southern Utah. Guidance shows a fairly well-defined shortwave
    moving around the western periphery of the upper high, which along
    with PWs over 1.5 inches in many spots, and highly sensitive soils,
    will likely generate additional widespread storm coverage and flash
    flooding concerns. Given the synoptic setup and anomalous
    moisture, this can be considered a high-end Slight for parts of the
    region and a future upgrade may be required.

    ...Central Appalachians and Ohio Valley...
    A Slight Risk remains in place across portions of the central
    Appalachians and Ohio Valley. Moist soils and flood-prone mountain
    terrain are likely to contribute to the flash flood threat across
    this region. Deep moisture (PWs around 2 inches) will fuel showers
    and storms ahead of a strong cold front advancing southeast across
    the region. These storms will be capable of producing 1-2 in/hr
    rainfall rates, raising flash flooding concerns.

    ...Mid Atlantic...
    A separate Slight Risk has been introduced along the Mid Atlantic
    Coast for late Tuesday into early Wednesday. Strengthening
    southeasterly flow ahead of the system moving through the Ohio
    Valley will transport a deeply anomalous moisture plume into a
    region of strong ascent. This combination will support increasing
    coverage of showers and storms capable of producing heavy rainfall.
    While the exact spatial coverage of heaviest amounts remains
    somewhat uncertain, portions of the the more flood-prone urbanized
    I-95 corridor appear to likely be impacted, warranting the upgrade
    to a Slight Risk.

    ...Gulf Coast...
    With the heavy rainfall footprint associated the Gulf disturbance,
    remaining offshore in most of the guidance, continued to maintain
    only a Marginal Risk along parts of the immediate Gulf Coast.

    Pereira


    Day 4 and Day 5 Valid 12Z Wed Jul 22 2026 - 12Z Fri Jul 24 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE COASTAL
    CAROLINAS AND SOUTHEAST VIRGINIA ON BOTH WEDNESDAY AND THURSDAY...

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE INTERMOUNTAIN WEST ON WEDNESDAY...

    ...Tidewater Region of Virginia and the Carolinas...

    A slow-moving cold front pushing southeast out of the Mid-Atlantic
    on Wednesday is likely to continue slowing down its forward speed
    as it approaches the Tidewater Region of Virginia and the Carolinas
    on Wednesday. Meanwhile, plentiful tropical moisture will be drawn northeastward from the tropical system that will likely be
    meandering somewhere near the Louisiana coast on Wednesday. This
    moisture will ride northeastward ahead of the front, spiking PWATs
    above 2.25 inches over this entire region. The result of a strong
    but slow-moving front, well above normal amounts of moisture, and
    upper level support in the form of a deep trough over the Northeast
    supporting the surface front from behind/north will make for a
    nearly ideal scenario for training and backbuilding storms from the
    afternoon through the evening.

    This Day 4/Wednesday period is likely to be the fourth consecutive
    day that showers and thunderstorms have been dropping locally very
    heavy rain and multiple-inch rainfall totals somewhere in and
    around eastern North Carolina. The front will act to greatly expand
    the footprint of heavy rainfall in this area. Since soils are all
    but certain to be nearly saturated in this area by Wednesday, flash
    flooding concerns continue to increase. Thus, a higher-end Slight
    was introduced with this update from Raleigh east, and from
    Wilmington north through the Hampton Roads area. It's probable that
    should the trends continue to increase both with the expected
    rainfall on Wednesday, and the prior days' rainfall in this same
    region, that a Moderate Risk upgrade will be needed with future updates.

    By Day 5/Thursday, the front will sag a hair bit further south,
    likely sparing the Raleigh and Hampton Roads metros from much
    additional rainfall, but instead concentrating the heaviest rains
    from the Outer Banks southwest down the coast through Wilmington
    and including Charleston, SC in heavy rainfall. The ERO thus was
    started this morning with a Slight Risk for this area. Of course,
    even just a small increase in forward speed will push the front up
    to the coast, which would then concentrate all of the heaviest
    rains off the coast, making the Slight Risk an over-forecast.
    However, any slower/westward positioning of the front will make
    for a 5th consecutive day of heavy rains in eastern North
    Carolina...meaning the Slight Risk would be an under-forecast.
    Thus, the Slight represents the "happy medium" of these scenarios
    and fits best with the current rainfall forecast in the area for Thursday.

    ...Intermountain West...

    A Slight Risk upgrade was introduced with this update for a portion
    of the Intermountain West on Wednesday. The area highlighted
    includes all of southeastern Idaho, much of western Wyoming outside
    of Yellowstone, as well as far northern Utah and the northwestern
    corner of Colorado. Well above normal amounts of atmospheric
    moisture to the tune of up to 4 sigma above normal, and PWATs
    locally exceeding 1.25 inches will be in place across this region.
    An approaching longwave trough will direct a strong shortwave
    northeastward during the afternoon hours. This will result in
    widespread shower and thunderstorm activity over this area.
    Topographic interaction with the storms will locally enhance
    rainfall rates, while also supporting impactful flash flooding as
    the rain water races down the slopes of the mountains. Due to the
    abundant moisture available, the storms will not only be numerous,
    but capable of 2 inch/hour rainfall rates with the strongest cores,
    a phenomenon not often seen in this part of the country.

    Wegman
    $$
    --- MultiMail/DOS
    * Origin: capitolcityonline.net * KY, USA (618:250/10)
  • From Mike Powell@618:250/10 to All on Mon Jul 20 07:16:50 2026
    FOUS30 KWBC 200827
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    427 AM EDT Mon Jul 20 2026

    Day 3 Valid 12Z Wed Jul 22 2026 - 12Z Thu Jul 23 2026

    ...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR THE CAROLINAS,
    PORTIONS OF THE INTERMOUNTAIN WEST, AND THE CENTRAL GULF COAST...

    ...Carolinas into Southeastern Virginia...

    A strong cold front that impacted much of the Mid-Atlantic on
    Tuesday will stall out over central Virginia on Wednesday. Ahead of
    the front, abundant Gulf moisture will continue streaming
    northeastward from Tropical Depression 2, likely to be centered
    south of the Mississippi Delta. Since the front will remain strong,
    and the moisture will remain well above normal for the Carolinas,
    as PWATs spike above 2.25 inches at times, the front will act as a
    train track for numerous training and backbuilding thunderstorms.
    The focus for these storms will be where the front interacts with
    the deepest moisture, which is expected from central North Carolina
    northeast through the Tidewater of Virginia.

    This area should get a break in the rain on Day 2/Tuesday, such
    that by the time the heaviest rains impact NC and VA on Wednesday,
    some draining from prior days' storms should work to limit the
    flash flooding risk somewhat. Thus, for now the area remains in a
    higher end Slight. The forecast rainfall will continue to be
    monitored as a Moderate Risk upgrade remains a possibility.

    ...Central Gulf Coast...

    Tropical Depression 2 is expected to be drifting west to the south
    of Louisiana on Wednesday. The conditions impacting the system will
    remain much the same on Wednesday as on prior days. Northerly shear
    will remain in place, pushing most of the associated convection
    south of the circulation center, keeping nearly all of the heaviest
    rains over the Gulf. Only a tiny fraction of the storm's overall
    rainfall will impact land areas, with the best chance expected
    along the immediate Gulf Coast of southeastern Louisiana. The
    inherited Slight Risk was trimmed to just the immediate coast,
    dropping the threat for metro New Orleans, in coordination with
    LIX/Slidell, LA forecast office. Of course, trends in the storm
    will continue to be monitored, as subtle changes in the environment
    around the storm could result in large changes in the rainfall forecast.

    ...Intermountain West...

    The combination of well above normal moisture across much of the
    intermountain West on Wednesday, strong upper level disturbances
    tracking northeastward ahead of a longwave trough over the Pacific
    Northwest, and numerous mountain ranges will all work to promote a
    much higher than normal flash flooding potential over the area from
    the 4 Corners north through much of southeastern Idaho. The Slight
    Risk for Idaho and Wyoming was expanded south due to yet another
    day of expected showers and thunderstorms impacting the highly
    flash flooding prone areas of Utah and western Colorado. The
    greatest rainfall totals are likely into northwestern Wyoming, from
    Yellowstone south. Few changes were needed north of Wyoming's southern border.

    Wegman


    Day 4 and Day 5 Valid 12Z Thu Jul 23 2026 - 12Z Sat Jul 25 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    CENTRAL PLAINS TO LOWER MISSOURI VALLEY, THE CENTRAL TO WESTERN
    GULF COAST, AND THE EASTERN CAROLINAS ON DAY 4...

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    LOWER MISSOURI AND MID MISSISSIPPI VALLEYS, AND THE EASTERN
    CAROLINAS ON DAY 5...

    ...Southeast...
    A moisture-laden front will continue to sink slowly south across
    the region. While the overnight guidance continues to present
    differences on the timing of the front and corresponding
    precipitation, there remains a strong signal for additional heavy
    amounts impacting parts of the region, especially for portions of
    the Carolinas. PWs remaining around 2.25 inches along with periods
    of enhanced ascent will raise the threat for additional heavy
    amounts most likely centered over eastern North Carolina into
    northeast South Carolina Thursday into early Friday. Due in part to
    model differences and forecast uncertainty, maintained a Slight
    Risk. However, this has the potential to be a second day in-a-row,
    and the fourth day this week for heavy rains impacting parts of
    the region. Therefore, if forecast confidence increases and the
    signal for a multi-day heavy rainfall event holds, future upgrades
    may be required.

    For Friday into early Saturday, it remains a question
    whether the front will continue to push south, bringing drier
    conditions into the Carolinas as the GFS/UKMET indicate, or
    continue to hang up well to the north as shown by the ECMWF and
    Canadian. Opted for a Slight Risk on for the Day 5, centered
    similar to the Day 4 area, which presents a compromise between the
    two camps and lined up with the higher probabilities from the most
    recent ECENS.

    ...Gulf Coast...
    Shear across Tropical Depression Two is expected to keep the
    heaviest rainfall amounts associated with the system mostly south
    of the center and offshore. However, cannot rule out the threat for
    onshore flow supporting some locally heavy amounts along the coast,
    especially if the trends support a stronger system and more
    northerly track. Therefore, the a Slight Risk was maintained along
    the Louisiana to the upper Texas Coast on Day 4.

    A Marginal Risk was drawn for Day 5 from the upper Texas Coast
    inland toward south-central Texas, where heavy amounts are
    possible if the storm remains organized and continues to track west.

    ...Central Plains to the Mid Mississippi Valley...
    Models continue to show a well-defined shortwave sliding southeast
    off of the top of the western U.S. ridge through the northern
    Plains and into the mid Mississippi Valley on Day 4. Organized
    heavy rain may develop late Thursday into early Friday as this
    energy interacts with a deepening moisture pool fed by a
    strengthening southwesterly jet. A Slight Risk was maintained on
    Day 4 over parts of southeastern Nebraska into adjacent parts of
    Kansas, Iowa, and Missouri, where models indicate the deepest
    moisture, better forcing and greater potential for localized
    training will center. Storms continuing through Friday morning and
    possibly redeveloping later in the day downstream will extend the
    threat across across a greater part of the mid Mississippi Valley on Day 5.

    ...Southwest/Great Basin/Central and Southern Rockies...
    Monsoon moisture will continue to fuel diurnal activity, however
    the footprint is expected to diminish especially by Day 5 as
    moisture anomalies drop off and heights build across the Southwest.

    Pereira
    $$
    --- MultiMail/DOS
    * Origin: capitolcityonline.net * KY, USA (618:250/10)
  • From Mike Powell@618:250/10 to All on Tue Jul 21 09:13:58 2026
    FOUS30 KWBC 210847
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    447 AM EDT Tue Jul 21 2026

    Day 3 Valid 12Z Thu Jul 23 2026 - 12Z Fri Jul 24 2026

    ...THERE ARE SLIGHT RISKS FOR EXCESSIVE RAINFALL FOR A PORTION OF
    THE SOUTHEAST FROM GEORGIA THROUGH THE CAROLINAS AS WELL AS FOR
    NORTHEAST KANSAS AND SOUTHEAST NEBRASKA...

    ...Southeast...

    The stalled out front that has remained across the Southeast will
    continue to plague the area with very heavy rainfall, as the
    continuous stream of Gulf moisture from the Gulf funnels
    northeastward along the front. Yet another day of heavy rain is
    expected to impact the Carolinas as a result. The front may drift
    ever so slightly further south and east which should clear all but
    the Hampton Roads area of far southeast Virginia from the heavy
    rainfall threat by Thursday, but for much of eastern North
    Carolina, much of South Carolina, and portions of northern Georgia,
    generally from Atlanta east, the heavy rainfall threat will
    continue through Thursday. Once again, potential for very heavy
    rainfall totals in many areas as are expected to see heavy rain
    from Wednesday could mean further upgrades to the risks may be
    needed, especially across eastern North Carolina. Ultimately, where
    the heaviest rain falls both today and Wednesday should dictate if
    further upgrades will be needed.

    ...Central Plains...

    An MCS is expected to impact a portion of northeast Kansas,
    southeast Nebraska and the Kansas City and St. Joseph metros on
    Thursday. The heavy rainfall footprint has drifted south and west,
    so the Slight Risk has been adjusted accordingly. As with many
    MCS's the location of the heaviest rain is likely to continue
    shifting with future updates, most likely towards the south, so
    stay tuned for further updates. Periods of heavy rain may continue
    to impact Wyoming into Colorado as well, where upgrades to a Slight
    are also probable, depending on where the heavy rains from
    Wednesday overlap with Thursday's forecast.

    ...Bertha...

    Bertha, who may no longer be a tropical cyclone by Thursday, and
    likely to be in a weakening state, should continue to keep any
    associated rainfall off the coast. The immediate coast remains with
    the best chance for seeing anything over an inch of associated
    rainfall. FFGs are significantly higher than that in all areas.
    Given this, and with very good consistency in this scenario in the
    guidance, the inherited Slight and Marginal for a portion of the
    Texas and Louisiana Gulf coasts was removed with this update. The
    Marginal Risk has been downgraded to under a 5% risk for the upper
    Texas Gulf Coast, as well as the Slight for coastal Louisiana
    downgraded to a Marginal with this update.

    Wegman


    Day 4 and Day 5 Valid 12Z Fri Jul 24 2026 - 12Z Sun Jul 26 2026

    ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    LOWER MISSOURI VALLEY AND MID MISSISSIPPI VALLEYS ON DAY 4 AND FOR
    PARTS OF SOUTHEAST COAST DAYS 4 AND 5...

    ...Southeast...
    A multi-day rainfall event is expected to continue into the
    weekend, with additional heavy rains likely, especially for parts
    of southeastern Virginia and the Carolinas. The focus for these
    rains will be a slow-moving, moisture-laden front that is forecast
    to linger across the region through at least the first half of the
    weekend. Southwesterly flow ahead of a shortwave trough moving
    through the Ohio/Tennessee valleys will further fortify the already moisture-rich airmass, with models showing PWs increasing in
    excess of 2.25 inches (+2 to 3 sigma). This moisture, along with
    pockets of enhanced ascent afforded by mid-level energy, will
    support periods of heavy, highly-efficient rainfall. While areas of
    heavy rainfall are likely, forecast confidence regarding their
    placement remains limited due to continuing model spread with
    regards to the placement of the front, which will have impacts on
    where the heaviest amounts occur.

    ...Gulf Coast...
    Northeasterly shear and dry air north of the center should keep
    much of the heavy rainfall threat associated with T.S. Bertha out
    over the open waters. Also, there is some question regarding the
    intensity of the system and if it will retain a closed circulation
    as it moves from the Louisiana onto the upper Texas coasts early in
    the period. However, cannot not rule out an isolated threat for
    heavy rainfall and therefore maintained a Marginal Risk for now
    from the southwestern Louisiana to the upper Texas coasts on Day 4.

    ...Lower Missouri-Mid Mississippi to the Tennessee Valleys/Southern Appalachians...
    Ongoing storms associated with pooling moisture along a low-level
    boundary and ahead a mid-level shortwave dropping southeast may
    continue to support storms and the threat for heavy rains Friday
    morning (Day 4) across parts of the lower Missouri Valley. Storms
    are expected to wane by late in the morning, but there remains a
    model signal for new storms developing farther to the south and
    east as additional energy interacts with deepening moisture (PWs
    increasing to 2-2.25 inches) that will be supported by
    southwesterly low level inflow.

    As this energy spills farther south, it may help to organize heavy
    rainfall across portions of the Tennessee Valley into the southern Appalachians, where a Marginal Risk was introduced for Day 5.
    Forecast confidence was limited by model spread, however this may
    be an area where a targeted upgrade is required in a future update
    if confidence increases.

    ...Southwest/Great Basin/Central and Southern Rockies...
    After what is expected to be a downward trend in convective
    coverage and potential flash flooding late in the week (Day 4),
    moisture anomalies are forecast to increase again on Saturday. This
    increasing moisture along with mid level energy moving around the
    southwestern periphery of a broad high will help expand afternoon
    and evening storm coverage, including the southern Arizona deserts.

    Pereira
    $$
    --- MultiMail/DOS
    * Origin: capitolcityonline.net * KY, USA (618:250/10)
  • From Mike Powell@618:250/10 to All on Wed Jul 22 08:48:46 2026
    FOUS30 KWBC 220826
    QPFERD

    Excessive Rainfall Discussion
    NWS Weather Prediction Center College Park MD
    426 AM EDT Wed Jul 22 2026

    Day 3 Valid 12Z Fri Jul 24 2026 - 12Z Sat Jul 25 2026

    ..THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
    SOUTHEAST AS WELL AS FOR MUCH OF MISSOURI...

    ...Southeast...

    The front that has been causing heavy rain across portions of the
    Southeast through Thursday continues on into Friday, though begins
    to weaken and in some areas lift back to the north as a warm front.
    Due to this weakening forcing, the rainfall forecast footprint over
    the Carolinas diminishes substantially (by about half) as compared
    with prior days' rains. While many areas continue to see periods of
    heavy rain, which may overlap with heavy rainfall from prior days,
    the much lower rainfall forecast over North Carolina did allow for
    the risk level to drop back into the Slight category for the Friday
    period. That said, any increase in rainfall, especially for areas
    hit hard on Wednesday and Thursday, could easily necessitate
    another upgrade to a Moderate for portions of eastern North
    Carolina with future updates.

    The rainfall forecast increases from prior days further west into
    northern Alabama and Georgia. The inherited Slight risk, as on past
    days, was expanded west. In this case, the expansion went all the
    way to the Mississippi state line with Alabama, as Alabama in
    particular looks to have its wettest day of the week on Friday.
    Considering prior days rains forecast for this same area, more
    favorable hydrology and further increases in expected rainfall in
    northern Alabama and Georgia could mean a Moderate Risk upgrade
    with future updates isn't entirely out of the question. Certainly
    eastern NC has a much higher chance of this happening.

    ...Missouri...

    An MCS over the area Friday morning diminishes in intensity with
    differential heating over the Plains and Ozarks on Friday. However,
    guidance is not in good agreement as to whether or not the rainfall
    dissipates entirely. Peak heating could provide enough instability
    that the convective organization changes, but not its coverage.
    Thus, A Slight Risk for a large portion of Missouri remains in
    place. Any rain will continue in this area into Friday night.

    ...Texas..

    Regardless of whether Bertha does better at maintaining its
    intensity on Thursday, or if it dies earlier by taking a more
    northerly track, by Friday the rainfall associated with the storm
    will be long dissipated or diminished to nuisance showers. As
    such, all flooding risks directly associated with Bertha will be
    ended by Friday.

    Wegman


    Day 4 and Day 5 Valid 12Z Sat Jul 25 2026 - 12Z Mon Jul 27 2026

    ...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FROM THE MID
    MISSISSIPPI VALLEY TO THE SOUTHEAST DAY 4 AND ACROSS PORTIONS OF
    THE WESTERN U.S. DAYS 4 AND 5...

    ...Mid Mississippi Valley to the Southeast...
    The overall trend in the overnight guidance was to shift the slow-
    moving surface front and associated axis of deeper moisture farther
    east and off of the Southeast Coast on Saturday, diminishing the
    threat for widespread additional heavy rains across the Carolinas.
    Therefore, the Slight Risk was removed from the eastern Carolinas.
    However, cannot rule out an isolated threat for localized heavy
    rains and an isolated flash flood threat. Therefore, the Marginal
    Risk was maintained for the Day 4 period from eastern North
    Carolina into the Southeast before notably drier air begins to
    spread across much of the region on Sunday.

    The Marginal Risk was also maintained farther northwest back across
    the Tennessee Valley into the mid Mississippi Valley. Some models,
    more notably the ECMWF and UKMET, show elevated storms that are
    expected to develop Friday night continuing to propagate southeast
    from the mid Mississippi into the Mid South, with deepening
    moisture and training storms raising the potential for heavy
    accumulations. As the associated mid level energy continues to drop
    southeast, there is the potential for at least locally heavy
    amounts and isolated flash flooding concerns as it interacts with
    lingering deep moisture from the Tennessee Valley into Alabama and
    Georgia on Saturday.

    ...Southwest to the northern Rockies...
    After a dropoff late in the week, the footprint for diurnal
    showers and storms is expected to expand once again by Saturday as
    high moisture anomalies (+2 sigma) return to parts of Arizona and
    New Mexico. This moisture along with mid-level energy moving
    around the southern periphery of the high will raise the threat for efficient-rainfall producers, raising flash flooding concerns
    across parts of the Southwest both days. This elevated moisture and
    enhanced forcing may support the need for an upgrade to a Slight
    Risk in future updates.

    Meanwhile deeper moisture and energy lifting along the northwest
    side of the high will extend the threat into parts of the northern Intermountain West and Rockies on Day 4, before moisture anomalies
    drop off on Day 5.

    Pereira
    $$
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    * Origin: capitolcityonline.net * KY, USA (618:250/10)