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