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FOUS30 KWBC 011559
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1159 AM EDT Fri Aug 1 2025

Day 1
Valid 16Z Fri Aug 01 2025 - 12Z Sat Aug 02 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CAROLINAS, NORTH/NORTHEAST TEXAS, NORTHEAST NEW MEXICO AND THE
DAKOTAS...

...Southeast...

Scattered to widespread thunderstorms are expected today with
daytime heating broadly across the Southeast along and ahead of a
relatively strong cold front for mid-Summmer. Plentiful Gulf
moisture (mid-70s dewpoints) and instability (1000-2000 J/KG ML
CAPE with long, skinny profiles) will promote efficient rain rates
of 2"+ per hour. The lack of bulk shear will lead to mostly
shorter- lived outflow dominant storms, but given the high rain
rates a quick 1-3" could lead to some isolated flash flooding
issues. However, a focused corridor of more widespread, better
organized thunderstorms is forecast across portions of the coastal
Carolinas west into the southern Appalachians in vicinity of a
frontal wave and in the presence of slightly stronger bulk shear.
Additionally, a bit more anomalous PWATS (2-2.5 standard deviations
above the mean) will make it more likely that downpours with rain
rates higher that 2" per hour will be realized. Mean flow parallel
to the frontal boundary will also bring the potential for a few
repeated rounds/training of thunderstorms, encouraging locally
heavier rainfall totals. HREF probabilities of greater than 3" are
in the moderate to high range (40-90%) with probabilities of
greater than 5" between 40-60% along the coast with a secondary
maxima of low end probabilities (15-30%) along the southern
Appalachians. While FFGs along the Coastal Plain are expectedly
higher, the likelihood of the highest rainfall totals will still
bring at least a scattered flooding risk into urban areas.


...Southern Plains...

Further west, another frontal wave expected in northern Texas as
an upper-level shortwave passes overhead will promote a second area
of more concentrated thunderstorm development across northeastern
Texas. Similar to areas further east, plentiful moisture with
dewpoints hanging around the low 70s and similar instability and
CAPE profiles will promote heavy downpours, with updated HREF
probabilities of greater than 3" of rainfall between 40-60%. More
scattered convection could lead to a few isolated instances of
flash flooding more broadly across the Southern Plains.


...Rockies and Plains...

Scattered convection is expected across much of the Rockies and
High Plains in the presence of very moist, post-frontal upslope
flow. Regionally high dewpoints into the low 60s have been observed
this morning across the region which will help promote locally
heavy rain rates of 1-1.5" per hour, with the risk of isolated
flash flooding expected especially along some of the more terrain
sensitive areas.

A few areas of more focused corridors of convective coverage have
prompted Slight Risks. The first is over portions of central South
and North Dakota as a shortwave rounds upper-level ridging
overhead. Hi-res guidance has been consistently maintaining the
development of a more organized convective complex/mesoscale
convective vortex (MCV) into the evening/overnight hours forecast
to dive southeastward following the mean upper-level flow. The more
widespread, organized nature of the convection should lead to
locally heavier rainfall, with the HREF showing moderate to high
probabilities (40-80%) of greater than 3" of rain and at least low-
end probabilities of totals greater than 5" (15-40%).
Additionally, further west, a Slight Risk has been introduced over
portions of the northern Rockies as the attendant upper-wave will
help encourage another area of more widespread thunderstorm
development this afternoon. This region is also is experiencing
some of the highest anomalous moisture values over the CONUS
currently, approaching the 90-95th percentile for some locations.
Another area of focus will be along and ahead of the Sangre De
Cristo Mountains in northeastern New Mexico where more widespread
storms will lead to heavier rainfall totals. Hi-res guidance
supports areal average of 1-2" and the risk for more scattered
instances of flash flooding.

Putnam


Day 2
Valid 12Z Sat Aug 02 2025 - 12Z Sun Aug 03 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHEAST AND THE CENTRAL/SOUTHERN PLAINS...

...South and Southeast...

During this period the strong cold front will sink southward
through the Southeast, Deep South and westward in to Texas. A deep
pool of moisture will remain readily available enhance local
rainfall, especially with the presence of instability along and
ahead of the front interacting with the right entrance region of
the upper jet. Very heavy rainfall rates are expected and should
drive an isolated to scattered flash flood risk. The Slight Risk
are was maintained for portions of the Low Country South Carolina,
southern Georgia and far northern/northeast Florida and was
expanded western into Alabama with this issuance. The front
stretching west across the Gulf Coast states in a moist and
unstable environment could promote scattered diurnal thunderstorms
into Saturday thus maintaining the Marginal Risk.

...Rockies and Plains...

Shortwaves rounding the eastern edge of the upper ridge in the
western U.S. is forecast to interact with the same front that bends
back across the Great Plains, where rounds of rain and
thunderstorms are likely with possibly multiple MCSs. High rain
rates should be supported at times with the above normal moisture
and instability with some areas possibly seeing repeated rounds of
storms as the front begins to lift as a warm front. While the the
location of the heaviest accumulations remain somewhat uncertain
the guidance is favoring locations in the vicinity of western
Kansas and Oklahoma. A Slight Risk was upgraded for this portion of
the plains.

Snell/Campbell


Day 3
Valid 12Z Sun Aug 03 2025 - 12Z Mon Aug 04 2025

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR SOUTHEAST
GEORGIA AND FOR THE CENTRAL/SOUTHERN PLAINS...

...Southeast...

Once again the cold front advances further south, shifting the QPF
footprint along with it. The heaviest rainfall will likely focus
along the far southern portions of South Carolin and coastal
Georgia, therefore kept the Slight Risk for this period. A broader
Marginal Risk area covers the potential for isolated instances of
excessive rainfall as far west as the Florida Panhandle and
southeast Alabama.

...Plains...

MCSs mentioned in the Day 2 period will persist during this period
although shifted east/south further into the plains. Deep influx of
PW near 2 inches will continue to fuel convection and enhance
rainfall rates within these complexes. The exact location of the
highest totals are not certain but the higher potential for
excessive rainfall and flash flooding concerns will likely be
focused over south-central Kansas and northern Oklahoma. The Slight
Risk area was maintained for this period.


Campbell


Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt