FOUS30 KWBC 110851
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
451 AM EDT Sat Jul 11 2026

Day 3 Valid 12Z Mon Jul 13 2026 - 12Z Tue Jul 14 2026

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

...Central Gulf Coast to the Southeast...
The inherited Slight risk across portions of the central Gulf Coast
has been maintained and expanded both westward into southeast TX
and eastward into the FL Panhandle. A favorable synoptic and
mesoscale setup for training and backbuilding is forecast to align
with coastal areas. Enhanced west to northwesterly low level flow
south of the persistent shortwave/low over the TN/GA vicinity will
converge with southwesterly inflow off the Gulf. This configuration
is conducive for upwind propagation and some training convection.
While some uncertainty remains regarding how far inland the heavier
totals will reach, the moist airmass characterized by PWs around
2.25" will support heavy rainfall rates.

Further west, increasing low level southerly moisture transport
out of the western Gulf will push up the Rio Grande Valley and into
central TX, potentially resulting in convective clusters Monday
night. Future shifts may need to expand the Slight risk even
further into TX depending on how this threat evolves.

A broad Marginal risk remains in place from TN into the Southeast
and southern Mid-Atlantic, Similar to day 2, a lingering
shortwave/low will continue to interact with a backdoor frontal
zone. Model divergence exists regarding the exact positioning of
these features and the available instability footprint by this
time. Given this, and the fact that model QPF signals are a bit
more muted compared to Sunday, we will maintain the Marginal
risk...although an embedded Slight risk upgrade may still
eventually be needed as the mesoscale details clarify.

...Southwest...
A Marginal risk is maintained from southern NM into AZ, southeast
CA and southern NV. Deep monsoonal moisture will continue to push
northwestward with isolated to scattered convection expected TO
result in at least a localized flash food threat.

Chenard


Day 4 and Day 5 Valid 12Z Tue Jul 14 2026 - 12Z Thu Jul 16 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ALONG PARTS OF THE
CENTRAL GULF COAST ON MONDAY...

...Southeast U.S. into Texas...

Lingering effects from elevated moisture and slowly decaying
quasi-stationary front across the Southeast U.S. will lead to one
last period of elevated convective enhancements from east TX
through the southern half of the Southeastern CONUS. PWAT anomalies
will remain generally seasonal to perhaps upwards of +1 standard
deviations over the region, enough of a threat for heavy rain
prospects in a environment that favors relatively slower cell
motions. Considering the fact some of the Southeast will have
received a formidable amount of rainfall leading into the D4, some
localized flash flood concerns will linger for at least one more
day before finally waning into the D5 where the risk over the
Southeast is void and we settle into a more benign pattern overall.

Further west into the western half of TX, the same story cannot be
said as the pattern will begin shaping up into a much more
favorable flash flood environment thanks to a shift in the mid and
upper level pattern west of the Mississippi. Dominant ridging over
the top into the northern tier of the CONUS will give way to
a broad inverted trough axis migrating westward into the Southern
Plains as we move into the middle of next week leading to weakening
flow aloft and a myriad of smaller mid-level perturbations rotating
under the dominant cyclonic flow. Lowering heights and regional
forcing align to foster a more suitable convective environment
across the western half of TX with an emphasis currently on
west and southwest TX as noted via the multi-model consensus in
both the deterministic and ensemble outputs. Some of the guidance
is incredibly aggressive in their presentations with several inches
of rain in both the D4 and D5 time frames with a general maxima
located over the Lower Trans Pecos over into the neighboring
Edwards Plateau where the pattern would allow for greater low-level
convergence and prospects for organized convective clusters to
sneak out of Mexico (Mexican State of Coahuila). Considering a
solid agreement within the model suite this evening, felt confident
enough to introduce a SLGT risk across southwest TX over into the
Edwards Plateau and portions of the central RGV. This is certainly
an area to monitor closely as significant rainfall potential is
plausible in the current synoptic evolution being depicted.

...Southwest U.S...

The Southwestern U.S. will lie within the western flank of the
broad ridge pattern over the Central and Eastern U.S which will
provide a dominant southerly flow over the region allowing for
continued moisture advection and enhanced surface troughing over AZ
up through the Great Basin. This pattern is a continuation of the
Monsoonal presence out west with a potential for increasing flash
flood prospects as multi-day impacts could spur targeted
opportunities for repetition of areas getting hit by convection in
consecutive periods. This setup remains very stable in terms of the
broad synoptic pattern in place over the western CONUS, however we
will see a persistent moisture plume advect more formidable deep
layer moisture poleward as we move into early-mid next week leading
to PWAT anomalies pushing the 90-99th percentile according to the
NAEFS and 00z ECENS outputs. The strongest anomalies will lie
within the Great Basin up into the Northern Rockies on D4 with some modification by D5, but still very much entrenched within the upper
bounds of the anomalies, especially over the Northern Rockies and
Interior Northwest. Increased upper troughing migrating from the
west will slide under the ridge across the Northern CONUS leading
to an enhancement for convective potential over a broader scope by
D5 with widespread thunderstorm prospects aligned from the Canadian
border in MT down through the Inter-Mountain West into the
Southwestern deserts. This setup can lead to sneaky significant
rainfall prospects for those in the interior with a more typical
Monsoonal presentation in the convective coverage.

Given the above variables, the MRGL was expanded north and
northwest for D4 into the Great Basin with another MRGL risk added
across the Northern Rockies in the western half of MT and northern
ID. D5 is a broad MRGL risk for much of the Southwest and interior
west, including areas that were omitted from the previous period(s)
MRGL risks. There is potential for targeted SLGT risks to be issued
in future updates as we move closer to the event, so please check
back over the next several days as the pattern becomes much more
active and favorable for flash flood prospects.

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

FOUS30 KWBC 120841
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
441 AM EDT Sun Jul 12 2026

Day 3 Valid 12Z Tue Jul 14 2026 - 12Z Wed Jul 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF TEXAS...

...Central TX...
A Slight risk continues over much of central TX, with a setup
similar to day 2. Model guidance forecasts strengthening 850mb
southerly moisture transport interacting with a weak mean flow
regime, keeping the threat of backbuilding and training convective
clusters. There is the potential for at least locally significant
flash flooding from the Edwards Plateau into portions of the TX
Hill country. Higher end Slight risk probabilities are warranted
for this corridor, and future upgrades to a MDT risk are possible.
Notably, the AIFS has been highly persistent over multiple cycles
in indicating a possible higher end event...and the AIFS has a good
track record highlighting organized heavy rainfall events. This
will be multi day threat over this region, and so hydrologic
sensitivity should eventually elevate, increasing the risk for
locally higher end impacts.

...Southeast...
A Marginal risk is maintained across the Southeast as the same
low/shortwave migrates slowly southwestward. Deep moisture will
remain plentiful with PW value over 2". However, uncertainty
exists regarding the position of the instability axis and overall
convective organization, and model QPF signals are a bit more
muted than on days 1 and 2. Nonetheless, because multiple days of
rainfall may start to saturate soils and lower FFG thresholds, an
embedded Slight risk area remains a possibility in future updates.

...Southwest into Northern Rockies...
A Marginal risk stretches from AZ into MT. An expansive plume of
deep moisture, featuring PW values near mid-July climatology
maximums will extend across this corridor. The strongest
instability will be focused at the ends of this axis, across AZ and
MT, with weaker CAPE profiles in between. Cape should still be
sufficient for isolate stronger cells and a localized flash flood threat.

Central and eastern MT will need to be closely monitored for a
potential Slight risk upgrade. An axis of strong instability is
projected across the state, overlapping with increasing easterly
low level moisture transport. While the mean flow is weak at 10-15
kts, cells could potentially grow upscale and forward propagate in
this environment. Given the high rainfall rate potential,
convective trends will be closely monitored.

Chenard


Day 4 and Day 5 Valid 12Z Wed Jul 15 2026 - 12Z Fri Jul 17 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
WEST TEXAS ON DAY 4 AND DAY 5...

...Texas...

An increasing threat for excessive rainfall is becoming more and
more pronounced as we move forward in time as consensus grows on a
prolonged heavy rain setup across portions of west TX with emphasis
on the Edwards Plateau, Big Bend, and parts of Hill Country. Dominant
ridging over the top into the northern tier of the CONUS will give
way to a broad upper trough migrating westward into the Southern
Plains along the southern flank of the ridge as we move into the
middle of the week. The introduction of troughing overhead will
lead to weakening flow aloft and a myriad of smaller mid- level
perturbations rotating under the dominant cyclonic flow. Lowering
heights and regional forcing align to foster a more suitable
convective environment across the western half of TX with an
emphasis currently on west and southwest TX as noted via the multi-
model consensus in both the deterministic and ensemble outputs. ML
guidance has also been suggestive of the same threat with the last
series of runs from both the AIGEFS and EC-AIFS ensemble coming in
very aggressive with their interpretations in current D3-5 QPF
output. This has also led to some correlation of elevated
probabilities within the ensembles, both ML and standard NWP for
24-hr totals each period >2".

01z NBM probabilities for >2" have risen to between 30-50% for the
D4 time frame with coverage extending from the Big Bend down into
Maverick County, a span that includes some major population centers
like Del Rio and Eagle Pass, TX. The 30-40% probs expand eastward
into the neighboring Hill Country as well, an area of interest the
prior D3 period, so there's a greater threat for overlap in this
current pattern. When you begin factoring the cumulative threat of
heavy rainfall, guidance has surely risen the bar in terms of the
potential with incredibly aggressive presentations allotting
several inches of rain for the D3-5 time frames. General maxima
continues to be focused over the Lower Trans Pecos over into the
neighboring Edwards Plateau and down through the central RGV where
the pattern would allow for greater low- level convergence and
prospects for organized convective clusters to sneak out of Mexico
(Mexican State of Coahuila). Considering a solid agreement within
the model suite this evening, felt confident enough to maintain a
SLGT risk on D4 with a high-end SLGT prospect now being factored
into the forecast as we move forward in time. Have also introduced
a SLGT risk across west TX over into the Edwards Plateau and
portions of the central RGV for D5 as the threat lingers into
Thursday before finally beginning to disperse by Friday, beyond the
D5 period. This is certainly an setup to monitor closely as
significant rainfall potential is plausible in the current synoptic
evolution being depicted, and further upgrades are not out of the
question as we move closer to the window of impact.

...Western U.S...

Very little change in the previous forecast with the pattern
repeating on the new D5 leading to general continuity in both the
D4 and D5 convective threat and risk areas. The Western U.S. will
lie within the western flank of the broad ridge pattern over the
Central and Eastern U.S which will provide a dominant southerly
flow over the region allowing for continued moisture advection and
enhanced surface troughing over AZ up through the Great Basin. This
pattern is a continuation of the Monsoonal presence out west with
a potential for increasing flash flood prospects as multi-day
impacts could spur targeted opportunities for repetition of areas
getting hit by convection in consecutive periods. This setup
remains very stable in terms of the broad synoptic pattern in place
over the western CONUS, however we will see a persistent moisture
plume advect more formidable deep layer moisture poleward as we
move into early-mid next week leading to PWAT anomalies pushing the
90-99th percentile according to the NAEFS and 00z ECENS outputs.
The strongest anomalies will lie within the Great Basin up into the
Northern Rockies on D4 with some modification by D5, but still
very much entrenched within the upper bounds of the anomalies,
especially over the Northern Rockies and Interior Northwest.
Increased upper troughing migrating from the west will slide under
the ridge across the Northern CONUS leading to an enhancement for
convective potential over a broader scope by D4, carrying into D5
with widespread thunderstorm prospects aligned from the Canadian
border in MT down through the Inter-Mountain West into the
Southwestern deserts. This setup can lead to sneaky significant
rainfall prospects for those in the interior with a more typical
Monsoonal presentation in the convective coverage.

With a very stable height field being depicted mid to late week,
the threat for widespread convective activity over a large portion
of the Western CONUS remains favored for a broad MRGL risk at the
current lead. The threat will likely induce some upgrade potential
on a day-to-day basis as we step forward in time and we get a
glimpse at previous period impacts and any overlap in where
activity could occur once again for areas hit previously. This is a
relatively solid signal at range, so the risk was deemed
reasonable as a MRGL with upgrades noteworthy once we get a better
focus on potential inside 72 hrs. D4 and D5 maintained a MRGL risk
in very similar areas with only minor deviations in the orientation
of the risk from D4 to D5.

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

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)

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)

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)

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)

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)

FOUS30 KWBC 281352
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
952 AM EDT Tue Jul 28 2026

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

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

...Lower Missouri Valley into the Mid-Upper Mississippi Valley...
Shortwave energy will be progressing east southeast as it tracks
across parts of the central and northern plains on Thursday into
Thursday night/early Friday morning. The shortwave energy will be
encountering an increasingly moist and unstable airmass with
precipitable water values in excess of 2 inches being drawn into
the region ahead of the shortwave. Given the MCS/upscale growth
potential with this system, concentrated areas of heavy rain are
expected, especially across the Corn Belt. The Slight risk area
already issued for Thursday still covers the risk....especially
where the global ensemble probabilities of >3" in 12/24 hours are highest.

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

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

Bann


Day 4 and Day 5 Valid 12Z Fri Jul 31 2026 - 12Z Sun Aug 02 2026

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

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

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

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

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

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

FOUS30 KWBC 291137
QPFERD

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

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

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

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

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

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

Bann


Day 4 and Day 5 Valid 12Z Sat Aug 01 2026 - 12Z Mon Aug 03 2026

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

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

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

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

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

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

FOUS30 KWBC 020829
QPFERD

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

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

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

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

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

...Southwest/Southern High Plains...

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

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

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

...South Florida...

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

Campbell


Day 4 and Day 5 Valid 12Z Wed Aug 05 2026 - 12Z Fri Aug 07 2026

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

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

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

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

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

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

FOUS30 KWBC 120822
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
422 AM EDT Wed Aug 12 2026

Day 3 Valid 12Z Fri Aug 14 2026 - 12Z Sat Aug 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FRONT RANGE
AND HIGH PLAINS OF COLORADO, AS WELL AS PARTS OF THE UPPER MIDWEST...

...Colorado and Adjacent Areas...
An easterly low level jet branching off of broad southerly flow up
the Plains and around an expansive ridge to the east will support
a combination of upslope and convective rainfall across much of
northern Colorado on Friday. PWATs near the Kansas border will
approach 1.75 inches, lowering to around 1 inch into the Rockies
behind the Front Range. This ample moisture will funnel north and
west ahead of a large upper level trough expanding over the West
Coast to provide increasing synoptic lift through height falls.
Upper level shortwaves will also support more widespread convective
development across much of Colorado. The inherited SLGT area was
cosmetically adjusted over primarily NE Colorado where terrain-tied
storms may move slowly, or repeatedly, over areas that will also
receive heavy rain on Thursday to precondition the soils.

...Upper Midwest...
The inherited small SLGT risk was cosmetically adjusted to account
for new guidance, but in general changes were modest. There
continues to be quite a bit of uncertainty D3 as to the convective
evolution across the Upper Midwest. The region will remain firmly
entrenched within pinched mid-level westerlies north of an
amplified ridge, with low-level flow becoming easterly as a
seemingly semi-permanent stationary front wavers to the south. As
waves of energy ripple along this boundary and the periphery of the
ridge, another day of active convection with clusters of
thunderstorms is expected. The exact placement of this activity
remains uncertain as there are considerable latitudinal and
longitudinal discrepancies among the various models, but it is
likely that some areas will receive heavy rainfall once again on
Friday. Should this overlap heavy rain axes from D1 and D2,
upgrades to this risk area may be needed. However, at this time,
the threat appears slightly lower by Friday than
Wednesday/Thursday, and the SLGT was adjusted to match best the AI
QPF and the ECENS probabilities for 3"/24 hrs.

Weiss


Day 4 and Day 5 Valid 12Z Sat Aug 15 2026 - 12Z Mon Aug 17 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR NORTHEASTERN
COLORADO AND SOUTHERN WISCONSIN ON SATURDAY...

...Northeastern Colorado...

A third consecutive day of heavy rain into portions of northeastern
Colorado is expected on Saturday. A Slight Risk upgrade was
introduced with this update for this reason. A plume of moisture
that will have been in place across the region will still be in
place on Saturday. Meanwhile in the upper levels, the ridge over
the Southeast continues to gradually expand east along the Mexican
border. This will continue shifting the upper level flow from
southerly to southwesterly. Shortwave disturbances riding the top
of the ridge will continue tracking across the region, which will
provide ample forcing given the abundant moisture for widespread
shower and thunderstorm activity, including the potential for
backbuilding and training storms. While soils across much of the
upper Plains are very dry based on NASA Sport imagery, that
situation is likely to change, especially on Day 2/Thursday. With
repeated rounds of storms into Friday as well, by Saturday expect
much of this area to have saturated soils. Some of the guidance
suggests that Saturday will be the wettest of the upcoming days.
Thus, it stands to reason that additional upgrades may be coming
with future updates.

...Southern Wisconsin...

A Slight Risk was also introduced for southern Wisconsin with this
update. The combination of storms that originate in Colorado on
Friday, a plume of highly anomalous moisture riding the ridge, a
large trough over the northern Plains, and a strong cold front
moving in from the north will all play roles in setting up this
heavy rainfall event. The anomalous moisture will probably be the
single most important ingredient supporting heavy rainfall, as
PWATs exceed 2.25 inches in many areas. A morning MCS crossing the
area will start the soaking process for the soils, then new
convection will form overnight with the increase of the nocturnal
LLJ. The strong cold front will begin to clear the convection from
the northwest late Saturday night, eventually ending the excessive
rainfall and flooding threat. Urban and small stream flooding will
be the greatest threat, especially in areas such as Milwaukee.
However, given the impressive amount of moisture the storms will
have to work with, and the terrain in the area, flash flooding
could occur anywhere there is persistent heavy rain from training storms.

...Day 5/Sunday...

The heavy rain from the Wisconsin/Midwest region continues off to
the east on Sunday. Thus, the Northeast will have the greatest
threat for locally heavy rainfall. Unlike over the Midwest where
there will be an extended period where anomalously high PWATs over
2.25 inches will be in place, allowing storms to have more than
abundant fuels for flooding, by Sunday the entire complex of storms
will be much more progressive. However, that anomalous moisture
will still be there fueling the storms, and there still remains
some potential for training, especially where any storms form
ahead of the main line of storms. Thus, there is some potential
that some areas of the interior Northeast, generally along the I-90
corridor, could eventually need an upgrade. For now, primarily
given the average soil moisture and progressive nature of the
storms, a large Marginal has been introduced for all of the
Northeast outside of northern Maine.

Lingering storms into New Mexico and Colorado, then extending into
Kansas and Nebraska are expected Sunday afternoon. While the storms
may be numerous once again along the mountains, the coverage will
be much more widely scattered over the Plains.

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

FOUS30 KWBC 130904
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
504 AM EDT Thu Aug 13 2026

Day 3 Valid 12Z Sat Aug 15 2026 - 12Z Sun Aug 16 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FRONT RANGE
AND HIGH PLAINS OF COLORADO AND WESTERN KANSAS AND NEBRASKA, AS
WELL AS PARTS OF THE UPPER MIDWEST...

...Wisconsin to Ohio...
The favorable corridor for potential training convection shifts a
bit northeastward on Saturday into IL/WI and northern IN/OH as the
upper ridge to the south slowly shifts eastward and expands north.
Much of the same ingredients are in place from prior days...with
shortwave energy riding along the periphery of the ridge, an upper
jet to the north and strong low level moisture transport into the
northward lifting boundary. We do see a bit stronger forcing
develop by this time and an area of low pressure to the
north...which should help kick things eastward a bit more than
previous days. Nonetheless, the strong low level moisture transport
is supportive of some backbuilding near the warm front. Again we
see some latitudinal differences in the guidance...with our
preference continuing to stay on the southern edge of the model
spread. This aligns with typical biases, along with the better
performing AIFS and AIGFS, and the 00z RRFS (the only CAM that
goes this far out). So while some adjustments in the risk area are
likely, the corridor from northern IL into northern OH seems most
favored at this time.

...High Plains...
The wet pattern should persist across eastern CO into western
KS/NE. Scattered convection within a high PW and unstable airmass
will result in some cell mergers and heavy rainfall rates. Some of
these areas will likely be more hydrologically sensitive by this
time as well, with previous days rainfall increasing soil saturation.

Chenard


Day 4 and Day 5 Valid 12Z Sun Aug 16 2026 - 12Z Tue Aug 18 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL ON SUNDAY FOR
PORTIONS OF THE COLORADO FRONT RANGES AS WELL AS FOR THE MID-ATLANTIC...

...Colorado Front Ranges and High Plains...

The pattern of the previous days will continue into Sunday across
the High Plains. A large ridge covering much of the southern tier
of states finds its northwestern periphery over this region.
Another shortwave driving northeastward along the ridge interface
will spark yet another round of storms Sunday afternoon and
evening. This will be supported by an incredibly persistent pool of
anomalous moisture stuck over the area, likely due to the daily
rounds of storms that reinforce the atmospheric moisture in place.
Further, easterly flow into the mountains from off the Plains is
continually reinforced, including into Sunday. At the moment, the
guidance is not as aggressive on the rainfall amounts across
Colorado on Sunday as compared to previous days. This means Slight
level impacts will be more reliant on favorable antecedent
conditions across this area from previous days. There remains some
uncertainty specifically with how far south the storms will form.
Any offset of storm formation on Sunday compared to prior days will
greatly mitigate the flooding threat. Thus, there remains some
uncertainty with the location of the Slight. However, given the
persistent and unmoving pattern, there is enough confidence to
continue the Slight for yet another consecutive day.

...Mid-Atlantic...

A pair of fronts emanating from a low up over Quebec on Sunday will
sweep across the Mid-Atlantic. The warm front will come first,
advecting a plume of deep tropical moisture into the Mid-Atlantic.
PWATs will increase to over 2 inches in most areas with the warm
frontal passage. The front will move across this region from the
morning through the early afternoon. Widespread shower and
thunderstorm activity will be close on its heels. A cold front
tries to push across the area, but is likely to get hung up over
northern Pennsylvania Sunday night. This will keep much of the area
in the soupy warm and muggy air mass. A secondary low forms along
the fronts Sunday night, which will invigorate another round of
showers and storms likely persisting well into Sunday night.
Southwesterly flow aloft will support the storms' backbuilding and
persisting in this pattern as more moisture is advected into the
region ahead of the cold front. Urban and small stream flooding
will be the primary threats with these storms.

The Slight Risk area covers the mountainous regions of western
Pennsylvania and West Virginia which were both hit hard by recent
heavy rains, are prone to flash flooding due to the terrain, as
well as the urban area of Pittsburgh. The eastern part of the
Slight Risk area covers the I-95 corridor region from Wilmington,
DE through New York City. Of course, urban concerns will be a large
factor in any flooding concerns, as well as the increased danger
from the likely nighttime convection affecting the area.

...Day 5/Monday...

A series of Marginal Risks were drawn from New Mexico and Colorado
for continued afternoon convection (albeit on the down trend from
prior days), a MCS affecting portions of the upper Midwest and
northern Plains, continued WNW flow of deep moisture into the
mountains of Kentucky, West Virginia, and southwest Virginia, and
finally the approach of the same cold front that brings heavy rains
on Sunday to areas of the Mid-Atlantic further north brings rounds
of storms Monday to the Tidewater of Virginia and eastern North
Carolina. The Plains and coastal features are both quite transient,
and are likely to adjust in location and intensity over the coming
days. Meanwhile the Appalachians and High Plains areas have more
uncertainty on rainfall amounts over areas that have both been
hard-hit with heavy rains.

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

FOUS30 KWBC 150836
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
436 AM EDT Sat Aug 15 2026

Day 3 Valid 12Z Mon Aug 17 2026 - 12Z Tue Aug 18 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE OHIO AND TENNESSEE VALLEY AND APPALACHIANS, THE SOUTHWEST
AND UPPER MIDWEST ...

...OH/TN valleys into the Appalachians...
A southward dropping cold front will serve as a focus for scattered
convection on Monday. While overall storm coverage will be reduced
compared to previous days, lingering moisture and instability just
behind the boundary will maintain a heavy rainfall threat from KY
and TN into the central Appalachians, enhanced by local terrain
upslope. A Marginal risk is maintained for isolated flash flooding.

...Southwest...
A Marginal risk encompasses much of NM and adjacent portions of
southeast AZ and southern CO. Beneath an upper level ridge strong
instability and slightly above average PWs will interact with
embedded shortwave energy trapped in the weak flow. Terrain based
initiation is expected during the afternoon, with scattered
coverage and cell mergers likely as convection drifts off the
higher elevations.

...NE to MN...
A Marginal risk continues from central NE into southern MN ahead
of an advancing cold front. Frontal forcing will support convective
development with localized training or backbuilding potential
along the south to southwest flank of convection. While the threat
is expected to remain localized...and storms may prove progressive
enough to limit impacts...a Marginal risk reflects the low end risk.

Chenard


Day 4 and Day 5 Valid 12Z Tue Aug 18 2026 - 12Z Thu Aug 20 2026

...THERE IS A SLIGHT RISKS OF EXCESSIVE RAINFALL ON TUESDAY FOR
AREAS OF THE UPPER MIDWEST...

...Day 4/Tuesday...

Main threat for the CONUS on Tuesday will reside across the Upper Midwest/Mississippi Valley thanks to a strong mid-level trough
sliding out of western Canada providing a significant increase in
large scale forcing across the North-Central U.S. with a target on
the Upper Mississippi Valley into the Corn Belt as of the latest
ensemble and global deterministic trends. One of the main changes
from the previous forecast is a further south focus of the heavier
rainfall as the advancement of a cold front and elevated theta_E
advection will likely cause a development of widespread convection
further south than the previous forecast. The latest National
Blend came in further south as well, actually matching more of
the ML algorithms in the EC-AIFS and AI-GEFS ensembles meaning the
blend is shifting away from the previous northern output that put
the QPF maxima over MN. A deepening surface low materializing
within the diffluent mid-level evolution ahead of the trough is
slated to propagate southeast out of Canada with an expectation for
the low to strengthen quickly as it moves east- southeast over the
Upper Midwest. A trailing cold front will extend over the Dakotas.
through Iowa/Southern MN, arcing up into the northern Great Lakes
by the end of the period. Along and ahead of the front, widespread
convective initiation is forecast leading to a swath of heavy rain
prospects, including the opportunity for >3" of rain in areas
hardest hit. PQPF 90th percentile remains steady in its
presentation from previous forecasts depicting between 2.5-3"
across Iowa into southwest WI where the consensus is strongest for
where the heaviest precip potential may occur. ML guidance is also
in agreement on the heavy precip axis located in the same areas
across from IA to WI with the max located across Central IA as the
00z ML suite.

Considering the latest trends in guidance for a further south
impact in the heavy rainfall axis, the SLGT risk inherited was
shifted further south to encompass much of IA into WI. The shift
into IA is noteworthy due to the antecedent soil moisture that will
likely still remain elevated across much of the state due to the
previous periods of rainfall that generated widespread flash
flooding in the southern and eastern portion of the state. General
trends will be monitored closely as any overlap of the some of the
more sensitive areas in IA and WI could introduce some targeted
upgrades, especially with the signal likely to bear locally higher
totals compared to what is being forecast at lead. For now,
maintained the SLGT risk, but adjusted based on the latest shift in
the QPF mean further south.

...Day 5/Wednesday...

Broad ridging across the Southern CONUS and a deep, amplified upper
trough across Canada into the Northern U.S. will generate a
progressive flow that will entice periods of convection around the
western and northern periphery of the ridge with scattered heavy
rainfall signatures within those aforementioned domains. The most
notable area of precip will likely lie within the Great Lakes down
into the Ohio Valley where a cold front advancement will continue
to be a focal point for convection along and ahead of the front as
it migrates east of the Mississippi Valley towards the east coast.
Current signals are not as prolific as the previous periods of
excessive rainfall, however the antecedent soils will still likely
be in recovery over the areas of interest for the D5 leading to at
least isolated instances for flash flooding in the anticipated
evolution. Models remain mixed in their magnitude and location of
heaviest rainfall, but ensembles maintain some areal QPF maxima in
the vicinity of both the Great Lakes down through OH/KY into the
western half of WV. These areas are the most susceptible to
appreciable impacts given the nature of the soils allowing for at
least a MRGL risk to encompass the area to note the potential.

Across the Southwest into the Front Range, the western periphery of
the ridge will allow for a continued southerly push of warm, moist
air poleward with lee troughing likely to be situated from CO down
through NM as it materializes within a modest theta_E ridge.
Scattered thunderstorms across the terrain will transpire leading
to at least the threat for isolated flash flood prospects,
especially within any remnant burn scars and complex topography
within the Sangre de Cristos down into the Sacramento Mountains,
extending southwest towards the terrain of southeastern AZ into the
Bootheel of NM. A MRGL risk was added over the area to account for
the threat.

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

FOUS30 KWBC 160833
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
433 AM EDT Sun Aug 16 2026

Day 3 Valid 12Z Tue Aug 18 2026 - 12Z Wed Aug 19 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL PLAINS AND UPPER MIDWEST ...

A Slight risk is centered over IA and extends into adjacent
portions of northeast KS, eastern NE, northern MO, and northwest
IL. A stationary frontal boundary interacting with shortwave energy
diving southeastward within northwesterly flow aloft will serve as
the primary focus for heavy rainfall. Scattered convection during
the day should grow upscale into an MCS by late afternoon into the
evening as large scale forcing amplifies and the low level jet strengthens.

While the MCS is expected to eventually propagate southeastward
(limiting the overall duration of the flash flood risk), an
impressive instability pool featuring CAPE in excess of 3000 J/kg
and elevated PWs near 1.75" will support heavy rainfall rates.
Isolated to scattered flash flooding is possible before the systems
forward speed caps the threat. Guidance is now in good agreement
on the general axis which reflects a southwestward shift from
continuity. Given the climatological tendency for these setups to
trend further southwest with time, the Slight risk boundary was
drawn a bit broader to the southwest to accommodate potential
future adjustments.

Chenard


Day 4 and Day 5 Valid 12Z Wed Aug 19 2026 - 12Z Fri Aug 21 2026

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL ON WEDNESDAY ON
WEDNESDAY AND THURSDAY ACROSS PORTIONS OF THE SOUTHWEST, CENTRAL
PLAINS, OHIO VALLEY, AND MID ATLANTIC...

...Day 4/Wednesday...

Broad upper trough migrating across Canada with a stout upper level
ridge centered across the Southern Plains will lead to a fanning of
a cold front that will press south through the Ohio Valley into the
Mid Atlantic with aid from high pressure motioning through the
northern tier of the CONUS in wake of a low moving into eastern
Canada. The frontal positioning by mid-week will likely have the
cold front situated from the Great Lakes down through the Ohio
Valley with the western extension likely reaching back into the
Low to Mid-Mississippi Valley between MO/AR. Ensemble spread
frontal positioning is generally more latitudinal leading to some
back and forth with the positioning of convective initiation and
eventual impacts for Wednesday afternoon and evening. Consensus
will likely shift closer to the southern frontal positioning as
surface ridging has been gradually strengthening in the means over
the Northern U.S. which would help propel the front further south,
matching the ML placement as noted via both the theta_E gradient
forecast, as well as the mean surface wind direction off both the
AIGFS and EC-AIFS outputs.

Magnitude of rainfall will be subject to some variability at the
current lead as we will be missing more vigorous mid-level
disturbances that could contribute to a more prolific QPF signal.
That said, increased surface convergence in proximity to the front,
along with sufficient low-level buoyancy positioned south of the
boundary will likely provide enough support for scattered heavy
rain signals which are already showing up in individual
deterministic outputs. Globals have a smattering of elevated QPF
clusters within the confines of the frontal forecast from each
model, so it's just a matter of fine tuning the more intricate
details as we step forward in time. At this point, there was enough
of a signal to maintain the MRGL risk inherited over the Great
Lakes down into the Ohio and Mid-Mississippi Valley's with only
some minor adjustments necessary.

Further west, the western fringe of our ridge will maintain a
steady southerly low to mid-level flow capable of providing
consistent moisture and low-level theta_E advection out of Mexico
and tropics, up through portions of the Southwest into the Front
Range. Wednesday is shaping up to be active within the terrain from
southeast AZ up through north-central NM into the CO Front Range
leading to some scattered heavy QPF signatures embedded in the
mountains for each zone and across the High Plains of CO. Still not
enough of a signal, magnitude-wise to deviate from the inherited
MRGL risk, but will monitor closely if there are any targeted
upgrade potentials lying within portions of the Southern Rockies or
eastern CO.

...Day 5/Thursday...

Our aforementioned cold front will make headway through the Mid
Atlantic early Thursday with a round of convection likely to ensue
with the frontal arrival. A weak surface wave has also been hinted
off the Tidewater by Thursday afternoon and evening which could
enhance the convective environment locally over the Southern
Delmarva into the VA Tidewater. The jury is still out on this
particular feature, but it has some merit with the recent ML
outputs pinpointing a maxima in that general vicinity. In any case,
elevated PWATs along with the frontal approach should be sufficient
to provide enough support for locally heavy rainfall for those
above areas, extending back into VA through the Ohio and Tennessee
Valley's. Cold front will be slowing substantially by Thursday
afternoon thanks to resistance from the surface ridge positioned
over the Lower Mississippi Valley and Southern Plains. This setup
would be conducive for enhanced low-level convergence with the
front, and environmental conditioning over the Southern half of the
CONUS will be favorable with a rich airmass providing necessary
buoyancy to entice thunderstorm activity for yet another day in
proximity to the front. A MRGL risk is forecast within areas where
the front is expected to be present, or at least slowly move
through as the boundary will be the focal point for locally heavier
rainfall and potential training/slow-moving cells.

The Southwest into the Front Range remains active, once again, as
the ridge over the South dominates the pattern and provides general
persistence in the flow across the Southwest, along with buoyant
air being ushered poleward. A MRGL risk was added to the area in
question due to the consistency, but the western extent of the risk
is further back into AZ as there is a greater signal for moisture
getting pushed further west to enhance the convective scheme back
over the Mogollon Rim and surrounding terrain.

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

FOUS30 KWBC 180759
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
359 AM EDT Tue Aug 18 2026

Day 3 Valid 12Z Thu Aug 20 2026 - 12Z Fri Aug 21 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE OHIO VALLEY, MID ATLANTIC, AND SOUTHWESTERN U.S...

...Ohio Valley to Mid Atlantic...

Troughing for areas east of the Mississippi will continue with
modest amplification occurring as shortwaves dive down the backside
of the mean trough out of Canada and allow for further height falls
across the Ohio Valley to Mid Atlantic. Cold front from the past
few periods will continue making progress to the east coast with
the frontal positioning a critical part in the convective posture
over much of the above areas. The consensus for frontal placement
and eventual convective development puts the best opportunity for
heavy rainfall across the Tennessee Valley and the northern reaches
of AL/MS up through the central Mid Atlantic with the core of
heaviest rains focused along the Delmarva and VA Tidewater. Latest
global deterministic and ensemble means note a more robust low-
level convergence pattern initiating across the coastal areas of
the Mid Atlantic as the timing of the front coupled with diurnal
instability maxima and low-level convergence along the western
periphery of a ridge centered in the Atlantic will allow for a
heavier axis of QPF to materialize on Thursday afternoon and evening.

Proximity of the front will act as a focal point for the setup
with the projected low-level flow to run parallel to the front over
areas of eastern VA up through the Delmarva Peninsula with the
northern fringes lining through the southern half of NJ. Ensemble
mean QPF already shows a solid 1-1.5" areal QPF average with some
of the deterministic forecasting between 2-3" over the time frame,
a testament to a relatively steady signal with a relatively
pronounced range of 1-3" potential. NBM 90th percentile is also
solidly within that 2-3" range, albeit a much larger footprint of
higher totals with the heavy precipitation output even down into
northern NC. NBM probs for >2" are between 20-35% across all of the
Delmarva, extending south into the northern reaches of the VA
Tidewater. This signal has been consistent the past 4 cycles of the
NBM lending credence to the threat as the mean hasn't really
wavered much the past few days. In this case, the MRGL risk
inherited was maintained and will hold off on any upgrade until we
get closer to CAMs range heavier QPF signals may present themselves
if the synoptic evolution remains fixed to the area.

...Southwest U.S. into the Southern Rockies...

Relatively textbook monsoonal pattern across the west will lead to
scattered thunderstorm development across much of the Desert
Southwest extending north into parts of the Great Basin and through
the Southern Rockies. As of now, the signal is mainly seasonal with
regards to the PWAT anomalies and general expectation as the most
notable areas will likely be in those terrain focused zones across
AZ (Mogollon Rim), NM (Sangre de Cristos and Sacramento Mtns.), and
UT (Zion National Park). Low probs for >1" on the latest
ECENS/GEFS suites and 01z NBM allow for a standard MRGL risk
issuance for the area as the setup is genuinely favored for pulse
convection and slow cell motions tied to the terrain as a broad
597dm ridge centers over the Four Corners and makes little
progression in the D3 window. The previous MRGL was extended into
southern UT to account for the increasing signal in the area of
Zion National Park where slot canyons provide an inherent danger to
any slow moving thunderstorm activity.

Kleebauer


Day 4 and Day 5 Valid 12Z Fri Aug 21 2026 - 12Z Sun Aug 23 2026

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE SOUTHWEST AND MID-ATLANTIC...

...East...

Heading into Friday a mid to upper level trough will deepen over
the eastern U.S. resulting in a surface frontal boundary stalling
somewhere over the Mid-Atlantic. This setup remains favorable for
areas of heavy rainfall, as high PWs and strong instability
persists over portions of the area. However, model spread
introduces uncertainty regarding the strength and timing of
shortwaves traversing the trough, as well as the positioning of the
surface front.

The 00z GFS, AIGFS and CMC are notably more aggressive in pushing
the boundary southward, advecting drier air into the northern Mid-
Atlantic and displacing the heavy rainfall risk further south
across the Carolinas and far southern VA. Conversely, the ECMWF
and UKMET feature a stronger shortwave over the OH valley, keeping
the front further north and maintaining a heavy rainfall risk
northward into the Delmarva. Given these lingering spatial
discrepancies, uncertainty remains regarding where the optimal
overlap of forcing, instability and deep moisture will materialize.
While the setup needs to be monitored closely for potential
isolated to scattered flash flooding, a Marginal risk is maintained
given the low spatial confidence. Only a minor southward
adjustment was made to the risk area with this update...with a
larger shift withheld given we're still 4 day out and the ECMWF
and UKMET remain north.

By Saturday (day 5) the trough deepens further across the East. The
northern stream energy appears detached from the deep moisture
plume at this time. Thus, while rain is expected to stretch from
portions of the OH valley into the Northeast, it remains unclear
whether rainfall rates will be high enough to trigger flash
flooding. The coastal Carolinas currently represent the most
favorable zone for overlapping instability and high PWs, however
frontal timing and positioning are uncertain at this 5 day lead
time, and regional FFG thresholds are generally higher along these
coastal areas. As a result, no ERO risk area is delineated at this
time, although a Marginal risk may need to be introduced in
subsequent updates as guidance trends clarify.

...Southwest...

A Marginal risk remains in place across portions of the Southwest
for both Friday and Saturday, with the risk expanding slightly
northwestward on Saturday relative to Friday. A strong upper level
ridge will remain anchored over the region, trapping embedded
shortwave energy within the light flow. Plentiful monsoonal
moisture and instability will remain in play, making localized
flash flooding likely both days. Because convective forcing will be
primarily terrain induced, overall storm coverage should stay
below Slight risk thresholds. However trends will continue to be
monitored, as any increase in convective coverage/organization
within the favorable CAPE/PW footprint could support a more
concentrated flash flood risk.

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