FOUS30 KWBC 140803
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Sun Jun 14 2026

Day 3
Valid 12Z Tue Jun 16 2026 - 12Z Wed Jun 17 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE WESTERN AND
CENTRAL GULF COAST...

...South Texas...

The entire focus of heavy rainfall across South Texas Tuesday will
be the speed of movement of the upper level disturbance which
likely in part the upper level circulation of former east Pacific
tropical storm Cristina. The global guidance is in alright
agreement, but it could certainly be better. The EC is far slower
with its movement than the GFS. For this period, the difference
between the two is small enough that there is at least some
confidence in the subsequent meteorological effects. Essentially
the upper level Pacific moisture with Cristina will combine with
exceptionally deep Gulf moisture along the western periphery of the
Gulf, to raise PWATs to near record territory for this time of year
for some areas of deep south Texas, particularly along the coast.
With the disturbance in place, and strengthening with time, this
abundant moisture will be focused into slow-moving bands of heavy-
rain producing thunderstorms. PWATs will exceed 2.5 inches along
the coast, with some areas even nearing 2.75 inches. The exact
track of the slow-moving disturbance will be key as to who sees the
most rain, as the storms ride north off the Gulf and into coast to
the east of the center of circulation.

Rain wrapping around the circulation will spread west across all of
deep south Texas, right to the Rio Grande. This will lead to a
second consecutive day with exceptional rainfall totals in spots,
with areal average rainfall for the period likely exceeding 3
inches (with much higher localized amounts) from essentially
Galveston south and west. At the moment, the heaviest totals look
to concentrate for the portion of south Texas from Corpus Christi
south and west to the Rio Grande, but again any change in track or
speed of the upper low and any possible surface circulation will
change this dramatically. Regardless, considering the overlap from
the Day 2/Monday period, should this rainfall forecast remain
similar with future updates, a Moderate Risk will be necessary as
FFGs in this area will be much lower than they are now. Further,
there will be urban flooding impacts from Brownsville to Corpus
Christi as well.

...Louisiana into the South...

Up the coast from south Texas, the plume of abundant Gulf moisture
will continue to stream north into the slow moving front that will
remain set up from east Texas through northern Louisiana and into
western Mississippi. The good news for Tuesday is that the likely
influence of the upper level low over deep south Texas/Mexico will
make for downstream ridging, which should limit the coverage of
heavy rain from Houston east across the South. That said, the front
will still be a potent forcing feature, and training storms
tracking east parallel to the front will still pose a localized
flash flooding problem. Thus, the inherited Slight for this region
remains in place, especially considering the likely much more
favorable hydrology as this will be the second or third day
(depending on where you are) of heavy rain for this region. This
will likely offset the somewhat lighter rainfall totals expected
Tuesday and Tuesday night. A faster forward speed of the upper
level disturbance could also re-increase the rainfall forecast for
this region and also push some areas close to Moderate Risk
territory with future updates.

Wegman


Day 4 and Day 5

Valid 12Z Wed Jun 17 2026 - 12Z Fri Jun 19 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
MIDDLE MISSISSIPPI VALLEY, OHIO VALLEY, MID-SOUTH, AND GULF COAST
ON DAY 4 AND DAY 5...

An anomalous upper-level pattern will be the catalyst for active
days 4-5 timeframe from the Gulf Coast on north to the OH Valley
and as far east as the central Appalachians. Southeast TX and
portions of the Deep South will also experience widespread thunderstorms.

On Day 4 (Wed.) a robust 500mb vorticity maximum will spawn a
strong area of low pressure at the nose of a 500mb jet streak.
ECMWF SAT percentiles show show MSLP values that are among the
lowest in the CFSR database (1979-2009) over the Midwest by 00Z
Thursday that continue into early Thursday morning over the Great
Lakes. 850mb winds will be roaring to the tune of 50 kts and
potentially stronger than that over the OH Valley. The combination
of highly anomalous low pressure over the Midwest paired with high
pressure south of Bermuda will force Gulf moisture to race
northward into the Middle MS Valley and on east into the OH Valley.
With PWs also above the 90th climatological percentile, storms may
be fast movers, but they will contain efficient warm rain
processes. A Slight Risk was introduced from the MS Valley to as
far east as central OH to account for the increased flash flood
potential. Farther south, the pool of anomalous PWs accompanied by
a strengthening southerly IVT over the western Gulf will keep the
TX Coast at risk for Excessive Rainfall. While guidance still shows
some differing solutions, the region will only continue to see
soils grow more sensitive after multiple days of rain prior to
Wednesday. A Slight Risk was introduced for the Lower and Central
TX Gulf Coast, aligning with where the heaviest WPC QPF is located.

For Day 5 (Thurs.), between the NAEFS and ECMWF SATs, the
southerly winds within the 1000-500mb layer over the western Gulf
are remarkable with the entire layer's southerly wind anomalies
averaging at least the 97.5 climatological percentile. This means
the Gulf is wide open for business, not just with low-level
moisture but into the mid-to-upper levels as well. ECMWF and GEFS
ensemble means on Day 5 have PWs above 2.2" over the central Gulf
Coast with >90th climatological PWs as far north as the OH Valley.
A strong cold front will trigger widespread thunderstorms within
this environment that is likely to pose a flash flood threat in
portions of the recently more sensitive soils of the OH and TN
Valleys, leading to the issuance of a Slight Risk in these areas.
Farther south, guidance shows varying solutions of what could
transpire in east TX. The 12Z ECMWF EFI has a swath of >1 Shift of
Tails (SoT) from east TX to as far north as northern MS, and even a
small >2 SoT north of I-10 in east TX, indicating a signal for
locally significant rainfall being possible in these areas. The
details on the development of low pressure in the Deep South remain
unclear. That said, there is no denying the copious amounts of
moisture at these thunderstorms disposal and soils throughout the
region will have only grown more sensitive after multiple days of
Excessive Rainfall. A Slight Risk was introduced over the Upper TX
coast on east into southwest LA where it aligns with not only the
ECMWF EFI signal but the overlap with the more anomalous moisture
content and the heavier WPC QPF within the TX/LA area.

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

FOUS30 KWBC 150903
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
503 AM EDT Mon Jun 15 2026

Day 3
Valid 12Z Wed Jun 17 2026 - 12Z Thu Jun 18 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR THE UPPER
TEXAS GULF COAST INTO SOUTHWEST LOUISIANA...

...Upper Texas Gulf Coast into Southwest Louisiana...

A potent upper level disturbance which includes some of the upper
level remnants of former East Pacific tropical storm Cristina will
interact with an incredibly deep moisture plume over the western
Gulf to continue a multiple day heavy rainfall event over a small
portion of the upper Texas Gulf Coast on Wednesday. The disturbance
itself will make better forward progress during the period, moving
from off South Padre Island at the start of the period into western
Louisiana by Thursday morning. Immediately in advance of the center
of this low, heavy rains will continue into the upper Texas Gulf
coast and the Houston metro from the D2/Tuesday period. The axis of
heaviest rainfall through the day is likely to be directed east of
Houston, along the Texas/Louisiana border near Beaumont. Thus, this
area is likely to see the worst impacts from flash flooding overall
through the day. The strongest storms will become increasingly tied
to the movement of the surface low and attendant upper level
shortwave, as the front that plagued much of Texas will follow
behind the low, clearing much of the rest of the state from heavy
rains for a brief time. Across the South, the front that was
stalled from central Mississippi through Georgia the past few days
will dissipate entirely in advance of the next strong cold front.
tracking across the Midwest.

There remains considerable uncertainty as to how fast the low will
track up the Texas Gulf Coast towards the lower Mississippi Valley.
A faster progression may require a northeastward expansion of the
Slight to cover more of central Louisiana, and if even a bit faster
still, would re-impact western Mississippi late Wednesday night,
requiring a significant upgrade from the current blank ERO for that
area. Thus, significant changes are probable with future updates.

Since the upper Texas Coast area will have been hard hit on 2
consecutive days prior to Wednesday, the Moderate Risk continuation
into Wednesday was needed due to likely ongoing heavy rains through
the period. While there's better certainty into southwest Louisiana
for Moderate Risk level heavy rains, the Houston Metro was included
in coordination with HGX/Houston, TX forecast office due to
uncertainty largely on Wednesday morning as to how far west the
heavy rain shield will extend at that time.

...Midwest...

A potent area of low pressure over the Plains at the start of the
period will progress east across the Midwest at a rather fast clip
through the day on Wednesday. As the low moves into the mid-
Mississippi Valley, it will increasingly tap into the large
moisture plume present across much of the Southeast. The low will
create its own moisture feed allowing the moisture to rapidly
advect into the Midwest ahead of the low. The area from northern
Illinois into Indiana has also been hard hit by periodic rounds of
heavy rain in recent days, allowing for moist soils and high river
levels to remain. Light rains at times are expected in the area
Tuesday afternoon and evening, but due to lack of moisture, no
significant flash flooding concerns are expected then. By Day
3/Wednesday however, the tap into the Gulf moisture will change all
that. Numerous showers and thunderstorms will develop along the
cold front ahead of the low as PWATs rise well above 1.5 inches,
reaching as high as 2 inches at times. This will support storms
capable of 1-3 inch per hour rainfall rates Wednesday afternoon
through the overnight. The storms will be very fast moving, which
will reduce the flooding threat, but the aforementioned moist
soils, urban concerns, and increasing availability of deep moisture
will all support the potential for widely scattered instances of
flash flooding.

Expect a warm front to move across the area around midday to early
afternoon, then a strong cold front to move through late afternoon
through the evening, which may consist of one or 2 lines of storms.
These lines of storms in rapid succession could support training-
like effects as far as flash flooding potential. Given the very
favorable hydrology for flash flooding, it's possible targeted
Moderate Risk upgrades may be needed for portions of the area,
particularly northern Illinois into northern Indiana, where a
higher-end Slight is in effect.

Wegman


Day 4 and Day 5

Valid 12Z Thu Jun 18 2026 - 12Z Sat Jun 20 2026

...THERE IS A MODERATE SLIGHT RISK OF EXCESSIVE RAINFALL FOR
PORTIONS OF THE LOWER MISSISSIPPI VALLEY & CENTRAL GULF COAST ON DAY 4...

Attention is on the multi-day Excessive Rainfall threat in the
Deep South where an abundance of tropical moisture will engulf
areas from southeast TX to as far east as GA. There are notable
timing differences across guidance on the placement of the heaviest
rainfall, and this will come down in large part to the development
of the low-level disturbance in the western Gulf. Both its
development and track will likely be troublesome for guidance to
key in on for another 24-36 hours until the circulation is formed
over South TX. That said, the region in total will have witnessed
multiple rounds of Excessive Rainfall, particularly east TX,
central and northern LA, and into western MS in lead up to Day 4.
The 12Z ECMWF EFI showed a notable overlap of >0.7 signals from
southwest LA on east into central MS, including at least a 2
contour on the Shift of Tails. In collaboration with several WFOs
along the central Gulf Coast and the Lower MS Valley, a Moderate
Risk was issued to account for the concerns of additional Excessive
Rainfall over areas that will likely be dealing with ongoing flash
flooding in the days leading up to Thursday. It is worth noting
that the same axis of anomalous moisture in the South will stream
north into the TN/OH Valleys. These areas will have the benefit of
strong synoptic-scale forcing to produce widespread thunderstorms.
A Slight Risk stretches as far north as southwest PA to account for
flash flooding in these more flash flood prone areas.

Day 5 will see a weak 500mb trough axis over central TX tap into
lingering tropical moisture along the Gulf Coast. Lower pressures
over the Rio grande and persistent high pressure east of the
Bahamas will maintain the seemingly endless moisture tap emanating
out of the Bay of Campeche. Moisture out ahead of the upper trough
will also collide with a frontal boundary that will extend across
much of the South. The future of the upper-level feature that
originated over South TX early in the week may also still play a
key role in Excessive Rainfall, especially from southern LA on
east into northern GA. Accounting for various ensemble guidance
tonight, there is a sufficient signal for Excessive Rainfall in
areas across the South that received copious amounts of rainfall
the first four days of the work-week to be concerned for more
scattered instance of flash flooding that could be locally
significant. A Slight Risk was issued from the Lower Rio Grande
Valley to as far east as the Appalachians of northern GA.

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

FOUS30 KWBC 160821
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
421 AM EDT Tue Jun 16 2026

Day 3
Valid 12Z Thu Jun 18 2026 - 12Z Fri Jun 19 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE LOWER MISSISSIPPI VALLEY THROUGH CENTRAL ALABAMA...

...Lower Mississippi Valley through Central Alabama...

The tropical low and its associated moisture are expected to start
the Day 3 period over northern Louisiana or western Mississippi.
The leading band of heavy rain will be ongoing from eastern
Louisiana into southern Mississippi. The low will slowly drift
eastward across Mississippi through the day, then gradually
increase its forward speed Thursday night as it tracks east across
Alabama and ends the period in northern Georgia. A very persistent
heavy band of rain will remain south and east of the low center
throughout the Day 3 period. This will focus the heaviest rains in
the Moderate Risk corridor from central Louisiana through central
Alabama. Prolonged southerly flow of the deep tropical moisture
with PWATs to 2.5 inches will support development and redevelopment
of convection ahead of the main band associated with the low. Thus,
heavy rain with multiple inches of rain per hour rain rates are
expected through the Moderate Risk area. Soils in Louisiana and
Mississippi are already saturated now even before Days 1 and 2's
rains. While some parts of central Alabama have dry soils, that
should change as the soils are primed today/Day 1. Thus, by Day 3,
the entire Moderate Risk area should have well wetter than normal
soils. Thus, hydrology will play a big role in flash flood
development. For western areas, nearly constant heavy rain in Days
1-2 will make flooding into D3/Thursday very easy. Further east
into Alabama, the southerly flow of deep tropical moisture will
last longer as the low tracks eastward, so there will be a longer
period where heavy rain may be occurring over Alabama. In
coordination with BMX/Birmingham, AL forecast office, the Moderate
Risk was expanded east across central Alabama with this update.
Even once the low center passes, the air mass will be largely
unchanged behind the low, as the tropical air mass will still be in
place into the lower Mississippi Valley, thus, the low's cold front
could continue to produce storms into southern Alabama into
Thursday night.

...Ohio Valley...

The northern edge of the deep tropical air mass supporting the
tropical low to the south will bump up against a strong cold front
that will be set up along the Ohio River on Thursday. As the
plentiful moisture on southwesterly flow runs into the front,
training thunderstorms are expected through much of Kentucky,
particularly the southern half, Thursday afternoon and evening.
This could lead to a prolonged period of heavy rain due to training
and backbuilding thunderstorms over the region. For this reason, an
internal higher-end Slight was issued for the southern 2/3 of the
state. The Slight into the mid-Appalachians was trimmed on the
northern side around Pittsburgh, PA due to less moisture making it
that far north and east, and with the cold front over Kentucky
concentrating the storms further west, coverage of storms into West
Virginia also appears to have diminished in the guidance. Thus, the
Slight was dropped to a lower-end Slight.

At the western end of the front into southeastern Oklahoma and
parts of Arkansas, an MCS may develop late Thursday night as the
nocturnal jet intensifies. A Slight Risk was drawn in from far
north Texas along the MO/AR border to the Mississippi/Ohio River
confluence for expected slow-moving and training storms along much
of the front, though the highest concentration of storms should be
into southeastern Oklahoma.

Wegman


Day 4 and Day 5

Valid 12Z Fri Jun 19 2026 - 12Z Sun Jun 21 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS, MID SOUTH, AND SOUTHERN APPALACHIANS ON DAY 4...

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER THE PARTS OF
THE MIDWEST ON DAY 5...

Day 4's (Friday) Excessive Rainfall threat remains fixed across
much of the South. The combination of the lingering disturbance,
that may become a more formidable surface cyclone, will reside
within an environment that contains >2.0" PWs over much of the
Mid-South. Sufficient instability aloft will continue to support
thunderstorms that can produce highly efficient rainfall rates.
Much of the region will also have received a steady dousing of
heavy rainfall during the work-week as well, priming soils for more
potential flash flooding. Farther west, a shortwave trough over TX
and the return of low-level SErly flow will introduce will
reintroduce more Gulf moisture over central TX and as far west as
southwest NM. The TX Hill Country is most prone to flash flooding,
although some localized flash flooding over the Guadalupe and
Sacramento mountains could also transpire.

By Day 5 (Saturday), a potent 500mb shortwave trough over the Great
Basin will race east towards the Northern Rockies around midday and
reach the northern High Plains by Saturday night. As a cold front
races south from Canada, a warm front lifting north through the
Central Plains will deliver a plume of anomalous moisture and
foster an increasingly unstable environment over the Midwest by
late Saturday. While the exact placement of the developing
thunderstorm activity varies by model, they all show a deepening
surface low over the Central Plains and a strengthening LLJ that
results in a >500 kg/m/s IVT field over the Midwest. Storms should
be able to produce efficient rainfall rates thanks to a growing
shield of >1.5" PWs over the MO River Valley, which does surpass
the 90th climatological percentile. For these reasons, a Day 5
Slight Risk was introduced. Farther south, a weakening frontal
boundary and residual anomalous moisture aloft will help trigger
additional storms from South TX on east across many of the Gulf
Coast States. Given the South's increasingly sensitive soils and
the presence of PWs hovering around 2.0", thunderstorms could
produce localized flash flooding Saturday afternoon and evening.

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

FOUS30 KWBC 170822
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
422 AM EDT Wed Jun 17 2026

Day 3
Valid 12Z Fri Jun 19 2026 - 12Z Sat Jun 20 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR MUCH OF
SOUTHERN ALABAMA...

...Southeast...

Any lull in heavy rainfall across southern Alabama from Thursday
night behind the precipitation shield associated with the remnants
of Potential Tropical Cyclone 1 will end in a hurry Friday morning
as the cold front over the Tennessee Valley continues to press
southward and runs into the ongoing southerly flow and low-level
jet of deep tropical moisture from off the Gulf. The clash of these
air masses looks to maximize over southern Alabama, where storms
are likely to continue in some form or fashion for much of the day
Friday. Assuming the multiple inches of rain from Thursday occurs
in these same areas, the slightly lower storm total rain on Friday
will make little difference for the flooding risk, as multiple
inches of rain fall over the same areas very hard hit from
Thursday. This very good overlap in the storm placement from
Thursday to Friday necessitated a risk upgrade across southern
Alabama for the Day 3/Friday period. Should this overlap continue
to hold and the widespread multiple inches of rain with localized
totals to double digits from Thursday occurs as forecast, it's
entirely feasible that the hardest hit areas may need further
upgrades to the flooding risk. Unfortunately the track record with
the CAMs ensembles on maintaining continuity day to day on where
the storms will occur is not very good, so any movement breaking
the overlap will greatly improve the rather ominous flooding
outlook for southern Alabama on Friday. Convective coverage over
Alabama should diminish greatly Friday night as heavier rains to
the west and the departing system to the east should put the state
in a relative ridging pattern, allowing for a much needed break
from the rainfall.

...Texas Hill Country...

Southeasterly flow of deep moisture from off the Gulf will
continue across much of Texas through the Day 3 period.
Northwestward moving convection on the leading edge of the deep
moisture will collide with storms that form along the dry line and
the Mexican mountains Friday evening, resulting in MCS development
that turns the storms back towards the best instability to the
southeast. This should result in some areas seeing multiple rounds
of heavy rain producing storms over the historically flash flood
prone region of the Texas Hill Country. Thus, a Slight Risk area
remains in effect for the region. Lesser amounts of rain are
expected further east into north-central Texas and the Metroplex,
so the Slight Risk inherited with downgraded in that area.

Wegman


Day 4 and Day 5

Valid 12Z Sat Jun 20 2026 - 12Z Mon Jun 22 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OF CENTRAL PLAINS THROUGH THE MID MISSISSIPPI INTO THE LOWER OHIO VALLEY...

Day 4...
A well-defined 500mb shortwave trough will move from the Great
Basin into the northern Rockies midday Saturday, reaching the
northern High Plains by Saturday night. Ahead of a southward
advancing Canadian cold front, a northward-lifting warm front
across the central Plains will lead an anomalous moisture plume
into an increasing unstable environment. While exact convective
placement varies, the deterministic models remain in generally
good agreement -- depicting a deepening surface low over the
central Plains that will help to focus moisture along the leading
edge of a strengthening low level jet. A deepening pool of
moisture (PWs increasing to 1.5-2 inches) over central
Nebraska/Kansas eastward into southwestern Iowa and western to
central Missouri will support efficient rainfall rates. This ample
moisture along with large- scale ascent afforded by mid-level
shortwave and right- entrance region jet forcing will further
encourage heavy rainfall and the potential for flash flooding
across the region. Therefore, a Slight Risk was maintained across
the region. Farther south, a weakening frontal boundary and
residual tropical moisture will trigger additional thunderstorms
from South Texas across the Gulf Coast. Localized flooding will
likely remain a threat given the increasing sensitive soils.

Day 5...
Forecast confidence lowers notably heading into the latter half of
the weekend as guidance begins to diverge on the track of the
leading wave forming over the central Plains on Day 4. Notably, the
ECMWF offers one of the more northerly solutions compared to other
guidance. Beyond the primary wave's track from the Midwest into the
East, considerable model spread exists regarding the timing of the
trailing front and subsequent wave and storm development. With the
continuation of ample moisture, instability, and strong forcing
areas of heavy rainfall and flash flooding appear likely. Given
the model spread, the outlook area, including a Slight Risk
extending from the lower Missouri to the lower Ohio Valley, relied
most heavily on a multi-model ensemble mean.

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

FOUS30 KWBC 180826
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
426 AM EDT Thu Jun 18 2026

Day 3
Valid 12Z Sat Jun 20 2026 - 12Z Sun Jun 21 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CENTRAL PLAINS AS WELL AS FOR PORTIONS OF THE SOUTHEAST...

...Central Plains...

A large area of heavy rain associated with a developing MCS
starting Saturday afternoon and continuing into Saturday night will
bring multiple inches of rain to a large area of southeastern
Nebraska through northwestern Missouri. Storms are expected to
initiate Saturday afternoon with peak heating. An LLJ of
southeasterly flow will pump deep Gulf moisture up the Plains
through the day. A developing surface low and upper level shortwave strengthening the low over Colorado will eject into the Plains.
This will force the dryline to race eastward in response. The warm
front associated with the low and the dry line will uplift the deep
moisture, resulting in widespread shower and thunderstorm
development in the form of an MCS. The MCS will track southeast
into southeastern Nebraska, far northern Kansas, and eventually to
the Missouri River. Additional storms capable of multiple inch per
hour rain rates will develop on the southern end of the MCS, where
the greatest rainfall totals will be. Urban areas in the path
including Lincoln and maybe Omaha, Nebraska, Topeka, Kansas, and
eventually St. Joseph and Kansas City, Missouri after midnight will
likely be impacted. Widely scattered instances of flash flooding
are likely. Given the amount of moisture present for these storms
to feed on and the urban areas likely to be impacted, additional
increases in forecast rainfall may require an upgrade to a Moderate
Risk with future updates. Since CAMs do poorly and the models
frequently shift where the heaviest rains will be leading up to an
event, the Moderate Risk was not considered at this time.

...Southeast...

An MCS tracking from the Ozarks following the same front that
entered interior portions of the Southeast as a cold front on
Friday will help that same front now retreat as a warm front on
Saturday. Heavy rains are expected Saturday morning over the Slight
Risk area from northern Mississippi to southern Alabama as storms
track southeastward along the retreating front. Daytime heating
will likely support additional clusters of storms into the
afternoon in these areas. The heaviest rains over the most
widespread area will be Saturday morning in northern Mississippi.
They will be less organized as they move into southern Alabama
Saturday afternoon, but given the prior day's expected rains in
these same areas, the Slight Risk includes southern Alabama as well.

Wegman


Day 4 and Day 5

Valid 12Z Sun Jun 21 2026 - 12Z Tue Jun 23 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
THE OZARKS THROUGH THE MIDWEST AND INTO THE UPPER OHIO VALLEY...

Day 4... By the start of the day 4 forecast period a potent
shortwave and related surface low are expected to eject eastward
out of the central Plains into the Midwest. There will also be a
trailing frontal boundary extending into the southern Plains to add
a focus for additional thunderstorms. There remains some
uncertainty regarding the speed and latitude of these features, but
PWs above the 90th climatological percentile (per the 00z GEFS)
overlapping with soils likely still recovering from recent heavy
rain in the Midwest will lead to at least scattered flash flooding
concerns. NBM probabilities for at least 2" are between 30-55% and
cover much of the SLGT risk area. Locally higher totals are likely
given the convective environment. The progressive nature of these
storms may end up limiting the severity of flash flood impacts, but
a MDT risk upgrade is possible should training/back-building
elements become more obvious in the short range updates. This is
especially the case given the sensitivity of the affected regions
to additional rainfall.

Day 5... The shortwave and low pressure on day 4 is forecast to
continue east towards the Mid-Atlantic and Northeast, with
additional uncertainties in latitude and speed. Additionally,
thunderstorms should reform along the attached frontal boundary
extending westward across the Tennessee Valley and into the
southern Plains. At the moment most convection appears scattered in
nature and low confidence in placement of heavier QPF. Therefore, a
MRGL risk is highlighted and will be refined in future updates.
Additional thunderstorm activity is likely into the High Plains,
with uncertainty surrounding the impact of a nearby southern Canada
upper low on thunderstorm activity in the northern High Plains.

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

FOUS30 KWBC 190728
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
328 AM EDT Fri Jun 19 2026

Day 3
Valid 12Z Sun Jun 21 2026 - 12Z Mon Jun 22 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM EASTERN
OKLAHOMA AND THE OZARKS THROUGH MUCH OF THE MIDWEST AND OHIO VALLEY...

...Midwest...

By the start of the day 3 forecast period a potent shortwave and
related surface low are expected to eject eastward out of the
central Plains into the Midwest. There remains some uncertainty
regarding the speed and latitude of these features, but PWs above
the 90th climatological percentile (per the 00z GEFS) overlapping
with soils likely still recovering from recent heavy rain in the
Midwest will lead to at least scattered flash flooding concerns.
NBM probabilities for at least 2" are very high (between 60-80%)
and cover much of the northern SLGT risk area from MO/IA to OH.
Locally higher totals are likely given the convective environment.
The progressive nature of these storms may end up limiting the
severity of flash flood impacts, but a MDT risk upgrade is possible
should training/back- building elements become more obvious in the
short range updates, particularly along the leading warm front
ahead of the primary surface low.

...Southern Plains, Ozarks, and Lower Ohio Valley...

The setup on Sunday could lead to a southern secondary axis of
heaviest QPF and flash flooding impacts. The southern end of the
Saturday night thunderstorm complex/MCS is likely to sink
southeastward near a trailing cold front and impact areas near the
Ozarks early Sunday. Then, the expectation is for reforming
scattered convection during peak daytime heating and reorganization
of thunderstorms overnight Sunday associated with the LLJ to span
from OK to the Lower Ohio Valley, including northern AR, southern
MO, and western TN/KY. This combines for guidance to currently
depict current QPF amounts of 2-4" and an average localized max of
6". There remains obvious mesoscale uncertainties at this stage,
but with Pws near the 90th climatological percentile and a
favorably oriented west- east frontal boundary, it's possible a MDT
risk upgrade may be needed once CAMs come into forecast range. For
the Lower Ohio Valley in particular, some guidance also highlights thunderstorms associated with the initial warm front lifting
northward, which could add yet another potential for slow-moving
repeating thunderstorms.

Snell


Day 4 and Day 5

Valid 12Z Mon Jun 22 2026 - 12Z Wed Jun 24 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
THE SOUTHERN PLAINS, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, AND
CENTRAL APPALACHIANS ON DAY 4...

Day 4 continues to an active pattern through a good portion of the
CONUS, east of the Mississippi with a progressive trough axis
pushing through the Great Lakes and Northeast leading to periods of
moderate to heavy rainfall from the Ohio Valley into the Mid
Atlantic and Northeast. Areas of the Northeast are subject to
thunderstorm prospects with the best chance for flash flooding
likely to occur in the urban footprint from Philadelphia up to
Boston with an expansion inland to the Hudson Valley down through
eastern PA. Current probs off the latest ensembles and National
Blend indicate a large zone of 50-80% probs for >1" across the
aforementioned area above with deterministic outputs closer to
2-2.5" into parts of Southern New England. MRGL risk inherited
remains in effect, but there's potential here for an upgrade as we
move closer to the D4 window, but want to see more of the CAMs to
make that decision.

Across the Southern U.S., heavy precipitation will preclude another
round of convection forming along a quasi-stationary front draped
from the Southern High Plains to the Southeastern CONUS. Probs for

1" are highest in-of the areas of Eastern OK into the Lower

Mississippi and southwestern Tennessee Valleys. Elevated theta_E's
and PWAT anomalies +2 dev. or greater indicate a formidable
environment capable of continued heavy rain potential that will
likely produce rainfall of 2-4", at least in some of the
thunderstorm activity that develops. The focal point along the
front will likely be where the heaviest rain will occur, or at
least be a low-level convergence mechanism that can enhance
regional convection. There's high enough confidence in the location
of convection for the D4 period to overlap with areas that will
have seen several inches the periods prior which led to an upgrade
to a SLGT risk positioned over portions of the Southern Plains
through parts of the Lower Mississippi and neighboring Tennessee
Valleys. The risk extends through the Smokey Mountains up into
parts of the Central Appalachians in eastern KY up into WV as the
convergence regime follows the frontal positioning over these areas.

Day 5 is a transition period into a more typical summer time regime
for the CONUS with a longwave trough over the Northern U.S. and a
dome of mid and upper ridging positioning itself across the
Southwest. This will cause a persistent northwesterly flow pattern
across the Central and Southern High Plains over into the Lower
Mississippi Valley as progressive shortwave pulses eject out of the
Rockies and ride the prevailing northwesteries in place between the
ridge and trough. This highlights potential for MCS development and
flash flooding scenarios from the Front Range and points southeast
as the steering flow orients between the base of the trough and the northeastern flank of the ridge. This is historically projecting a
case of thunderstorm maturation and upscale growth over the area
between CO/KS down through OK/TX with potentially the Red River
Basin as a focus for thunderstorm activity. Eventually this ends up
migrating into the ArkLaTex and/or Lower Mississippi area which is
showing up in the QPF footprint on ensembles. With this becoming a
more stable signal in the global ensembles and aligning with the
NBM QPF output, a MRGL risk was added to the new D5 to account for
this potential evolution.

Kleebauer
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