Subj : Heavy Rain/Flood TX Coast
To   : All
From : Mike Powell
Date : Wed May 28 2025 08:10:00

AWUS01 KWNH 281147
FFGMPD
TXZ000-281700-

Mesoscale Precipitation Discussion 0326
NWS Weather Prediction Center College Park MD
746 AM EDT Wed May 28 2025

Areas affected...Upper Texas Coast

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

Valid 281145Z - 281700Z

SUMMARY...Approaching complex of thunderstorms producing 1-2"/hr
rainfall rates may produce urbanized areas of flash flooding,
especially around the Houston metro area.

DISCUSSION...Vigorous thunderstorm activity along the Lower Texas
Coast is propagating northeast along a 925mb theta-e gradient that
is oriented SW-NE just south of I-10. The mean 925-850mb wind
field over the western Gulf is out of the SE with these winds
intersecting the nearby surface front located north of I-10 this
morning. This persistent SE flow will overrun the frontal boundary
and continue to act as a trigger for additional thunderstorm
activity. RAP mesoanalysis shows between 1,000-2,000 J/kg of
MUCAPE while PWs are steadily on the rise thanks to a southerly
IVT that is on the order of 300-500 kg/m/s. This allows for PWs to
rise above 1.75" along the Upper Texas Coast this morning with
some isolated areas approaching 2.0". RAP soundings are also
indicating highly saturated soundings and warm cloud layers up to
12,000ft deep in some cases.

The storms may extend farther inland to the north of I-10 as SErly
850mb winds accelerate. However, the concern for rainfall rates
>2"/hr is most likely along and south of I-10 where there greatest
instability is present. 06Z HREF probabilistic guidance shows a
bullseye of 30-50% values for 3-hr QPF > 3-hr FFGs near the
Houston metro late morning into early afternoon. As much as 1-3"
of rainfall is anticipated with localized amounts as high as 4"
possible within the highlighted threat region. These rates are
also coming around the morning rush hour within a densely
populated area. Flash flooding is possible this morning,
particularly in the more urbanized communities and poor drainage
areas of Southeast Texas.

Mullinax

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