Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Aug 21 2025 18:10:57

AWUS01 KWNH 211810
FFGMPD
LAZ000-TXZ000-220009-

Mesoscale Precipitation Discussion 0965
NWS Weather Prediction Center College Park MD
210 PM EDT Thu Aug 21 2025

Areas affected...portions of central through southeast Texas and
southwestern Louisiana

Concerning...Heavy rainfall...Flash flooding possible

Valid 211809Z - 220009Z

Summary...Scattered to numerous thunderstorm activity will pose an
isolated flash flood risk through 00Z/7p CDT this evening.

Discussion...Strong insolation/destabilization and the presence of
several meso-to-synoptic surface boundaries across the discussion
area has resulted in an uptick in coverage of thunderstorms over
the past half hour.  The storms are in a very moist/buoyant
airmass characterized by 2+ inch PW values and 1000-2000 J/kg
MLCAPE values, favoring the eventual development of heavy rainfall
rates as storms mature.  Additionally, storms are in a very weakly
sheared environment, with minimal steering flow aloft supporting
slow/erratic cell movement.  Areas of 2 inch/hr rain rates are
expected at times through the afternoon hours, which poses an
isolated flash flood threat.

FFG thresholds are generally in the 2-3 inch/hr range (locally
lower near urban areas near Austin/San Antonio and Houston.  These
thresholds and the pulse-type nature of the convection suggests
that any flash flood threat will be relatively isolated and
focused on urban and sensitive/low-lying areas.  The bulk of the
threat should be diurnally driven and exhibit a slow southward
propagation toward coastal areas through 00Z/7p CDT.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9cFes5Y2kLXFfF92YCZhfr1qVsSj3Fm0dTE8P-1aYNI55Ix-E8MQbfOkMMLjP0fQdIOh=
ZSn92Xz1I-85XNYNomPbsUA$  for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SHV...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON   31719608 31489428 31329243 30079263 29369463=20
            27699832 27719951 28070008 28930004 30049910=20
            30999761=20

=3D =3D =3D
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