Mesoscale Precipitation Discussion 0231
NWS Weather Prediction Center College Park MD
835 PM EDT Mon May 24 2021

Areas affected...Southeast Texas

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

Valid 250033Z - 250433Z

Summary...Complex of storms near Austin County, Texas has obtained
some mesoscale organization and will pose a continued flash flood
threat over the next couple of hours.

Discussion...Recent radar data indicated rotation and slow
eastward progress with the thunderstorm complex across Austin
County, Texas and vicinity.  Radar-based rainfall estimates are in
the 3-4 inch per hour range, which isn't surprising given the very
moist pre-convective airmass in place (1.8-1.9 inch PW values in
point forecast soundings).  Organization is likely being aided by
a slight uptick in southeasterly low-level flow into the complex
(estimated at around 25-30 knots at 850 mb).  This flow will
maintain a fetch of moderately unstable and moist air into the
complex.  Although somewhat uncertain, the storms could hold
together and approach western suburbs of Houston/Harris County
through 02Z.  Precipitation rates will easily exceed flash flood
guidance thresholds (1.5-2 inches per hour) given recent rainfall
over the past week and wet soils. 

Cook

ATTN...WFO...EWX...HGX...

ATTN...RFC...WGRFC...NWC...

LAT...LON   30529545 30299494 29829493 29479528 29519635
            29649687 29939695 30439684 30489626