Subj : Flood Threat TX/LA
To   : All
From : Mike Powell
Date : Fri Aug 22 2025 13:07:24

AWUS01 KWNH 221612
FFGMPD
LAZ000-TXZ000-222211-

Mesoscale Precipitation Discussion 0974
NWS Weather Prediction Center College Park MD
1212 PM EDT Fri Aug 22 2025

Areas affected...southeast Texas, southwestern Louisiana

Concerning...Heavy rainfall...Flash flooding likely

Valid 221611Z - 222211Z

Summary...Slow-moving convection continues to expand in coverage
this morning, with areas of 2-3 inch/hr rain rates becoming likely
beneath the strongest storms.  Flash flooding is expected.

Discussion...Deep convection has been focused mainly along coastal
areas of Texas and Louisiana for most of the morning.  Over the
past hour or so, storms has materialized just inland across the
discussion area (nearer to I-10) due to 1) strong surface
heating/destabilization, 2) abundant moisture (2.3 inch PW), and
3) convergence along a weak front across the region (generally
from Houston Metro east to Baton Rouge, LA).  Kinematics/steering
flow aloft are very weak (<5 knots), suggestive of slow-moving
cells/clusters that are outflow dominant and propagate erratically
through the afternoon.  A few of these clusters were forming near
Lake Charles and just north of Houston while already producing
spots of 1-2 inch/hr rain rates.

With continued surface heating, convective clusters are expected
to expand in coverage.  The orientation of storms relative to
outflow from prior activity over the Gulf suggests potential for
several cell mergers as well.  2-3 inch/hr rain rates will
eventually materialize, and may impact populated/flashy urban
centers such as Lake Charles, Beaumont, and Houston through 20Z. 
FFGs near those areas are as low as 1-1.5 inches/hr and should be
readily exceeded. Surrounding areas have higher FFGs (in the 3
inch/hr range) that should still be exceeded as stronger
convection develops through the morning and early afternoon. 
Areas of flash flooding are expected given the developing scenario.

Cook

ATTN...WFO...CRP...EWX...HGX...LCH...

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

LAT...LON   31019345 30519193 29869179 29589269 29619471 
            28749616 29029737 29879728 30399670 30939521 
            
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