360
FXUS02 KWBC 281957
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
357 PM EDT Thu Aug 28 2025

Valid 12Z Sun Aug 31 2025 - 12Z Thu Sep 04 2025

...Heavy rain and flash flood potential for portions of West Texas
and New Mexico this weekend into early next week...

...Overview...

The overall pattern will remain fairly stagnant through the medium
range period with mean troughing over the East and ridging over
the West. Shortwave energy cutting through the western ridge over
portions of New Mexico and West Texas and a developing weak low
pressure system in the Plains will create heavy rain threats on
Sunday and Monday. Meanwhile, a slow-moving frontal boundary will
sink into the northern Gulf, resulting daily rain chances across
the Gulf Coast states. Mid-next week, a strong upper low should
drop south towards the Great Lakes and push a cold front across the
Central U.S., resulting in well below average temperatures across
the Plains and Midwest.


...Guidance/Predictability Assessment...

Model agreement has increased since the overnight forecast with the
00Z and 06Z runs of the GFS trending closer to the ECMWF,
resulting a well clustered collection of model solutions from the
GFS/ECMWF/CMC and associated ensemble means. The UKMET represented
the pattern well but was displaced to the east compared to the
general model consensus, so it was excluded from the afternoon
forecast.

WPC`s afternoon forecast consisted of a blend of the deterministic
GFS/ECMWF/CMC for the first half of the period, and ensemble means
from the GEFS/ECENS/CMCE were added in increasing amounts through
the second half of the period.


...Weather/Hazards Highlights...

A surface front draped from the Southern High Plains across the
Gulf Coast and through the Southeast will be the focus for heavy
rainfall beginning this weekend. A moist monsoonal environment
with embedded shortwave energy aloft could produce flash flooding
over portions of southern New Mexico and far western Texas this
Sunday (day 4), where a Slight Risk (at least 15% chance) of
excessive rainfall is in effect. With anomalous moisture in place
and favorable surface and upper level dynamics, heavy rain appears
likely and may result in scattered instances of flash flooding,
especially in areas of steep terrain. A broader Marginal Risk will
extend across the southern tier along the front to account for
heavy rain fall potential in the Gulf Coast states and the
Southeast on Sunday and Monday.

The surface front will drift farther south into the Gulf on Monday
(day 5), and may refocus monsoon storms across New Mexico. Another
Slight Risk is in effect for day 5 across parts of southern New
Mexico and far western Texas. Elsewhere, a Marginal Risk area
remains over portions of the Northern/Central Plains and
Midwest/Mid-Mississippi Valley on days 4 and 5 due to a somewhat
progressive shortwave disturbance and weak surface low pressure
system propagating through the region, which will likely support
storms with elevated rain rates. There`s an increasing signal for
heavy rainfall to develop over portions of the Central/Southern
Appalachians on Monday beneath a digging upper trough in the East
and approaching shortwave, supporting a Marginal Risk in this area
as well.

Temperatures should remain below average beneath the Eastern U.S.
trough. A strong cold front will dive south through the Central
U.S. and bring well below average temperatures to the Plains and
Midwest by the middle of next week. Mean troughing in the Eastern
Pacific and persistent ridging in the Western U.S. should support
warm southerly flow into the West, resulting in above average
temperatures next week.


Dolan/Kebede


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw









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