Mesoscale Precipitation Discussion 0981
NWS Weather Prediction Center College Park MD
700 PM EDT Mon Oct 15 2018

Areas affected...Southeast TX

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

Valid 152300Z - 160500Z

Summary...Persistent showers and thunderstorms this evening will
increasingly lead to saturating soil conditions, and this may lead
to some flash flooding through the evening hours.

Discussion...The latest radar imagery shows an expansive area of
showers and embedded thunderstorms across the broader area of
southeast TX. Moist deep layer southwest flow overrunning a
surface cold front continues to generate plenty of large scale
isentropic ascent for the convection which is being aided by a
nose of elevated instability and also proximity of favorable
right-entrance region jet dynamics. MUCAPE values over southeast
TX are as much as 500 to 1000 j/kg and the PWATS are close to 1.75
inches which is helping to produce heavy rainfall amounts of as
much as 1.5 inches/hr within some of the stronger convective
cores.

The large scale dynamics aloft over the region are courtesy of an
upper trough amplifying into the Southwest U.S. and this should
maintain favorable right-entrance region jet forcing overhead
going through the remainder of the evening which coupled with the
nose of elevated instability should tend to maintain pockets of
heavier showers and thunderstorms.

Expect as much as 3 to 4 inches of additional rain going through
late evening where stronger convective cells tend to concentrate
and repeat over the same area. Given the gradual moistening and
saturation of the soil, some increased potential for flash
flooding will exist going through the evening hours.

Orrison

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

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

LAT...LON   31749454 31299402 30779422 30419483 30189574
            30229621 30599628 31089613 31669539