Mesoscale Precipitation Discussion 1046
NWS Weather Prediction Center College Park MD
938 PM EST Fri Dec 07 2018

Areas affected...East-Central TX...West-Central LA

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

Valid 080237Z - 080837Z

Summary...Widespread moderate to locally heavy rainfall across
interior east-central Texas into west-central Louisiana will
continue to saturate soils and may lead to flooding.

Discussion...As of 02z, an analysis showed surface low and
stationary boundary along the Texas Gulf Coast. Aloft, broad
southwesterly flow is evident with a large area of upper level
divergence across the southern Plains. There is a narrow axis of
frontogentically forced precipitation in the 850-925 mb layer,
which is contributing to steady moderate to locally heavy
rainfall. This is occurring on the gradient of the highest PWATs,
which are maximized along the coast around 1.9". These values are
2.5-3 SD above the mean for this time of year. MUCAPE as high as
250 J/kg extends up into east-central Texas. With the mean flow
parallel to the storm motion this evening and tonight, repeated
bouts of moderate to locally heavy rainfall are expected through
09z. Finally, since mid-afternoon, areal averages of 1 to 3" has
fallen, generally east of San Antonio to College Station to
Lufkin.

In water vapor, there is another mid/upper level wave noted across
south-central Texas. As this waves moves across east-central TX
into western LA, another wave of moderate to heavy rain will move
into the area. This is likely to produce hourly rates as high as
1" with totals of 2-4" possible. This rainfall, falling on
increasingly saturated soils, for a prolonged time could result in
flooding, especially over sensitive urban and poor draining
locations.

Taylor

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

ATTN...RFC...LMRFC...WGRFC...

LAT...LON   33119239 31919230 31059435 30539597 29639741
            29729812 30499810 31539711 32139589 32799403