Mesoscale Precipitation Discussion 0985
NWS Weather Prediction Center College Park MD
415 AM EDT Tue Oct 16 2018

Areas affected...Eastern Texas

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

Valid 160814Z - 161400Z

Summary...Numerous showers and thunderstorms aligned northeast to
southwest across eastern Texas into northwest Louisiana are
expected to move little through sunrise.  Rainfall rates are not
blockbusters, but the persistent training of cells over the same
spots will result in additional rainfall amounts of 2 to 4 inches
through 14Z.  This may lead to additional areas of flash flooding
while worsening any on-going flooding into the morning.

Discussion...The latest radar imagery still  showed an expansive
area of showers and embedded thunderstorms across from northwest
Louisiana into eastern Texas.  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 were still in the range of 500 to 1000 j/kg with and
the PWATS were at or above 1.75 inches.  This has been 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 into the morning.

Expect as much as 1 to 3 inches of additional rain...with higher
amounts certainly possible...through sunrise.  Given the
moistening and saturation of the soil, the potential for
additional flash flooding will continue.  The 06Z runs of the HRRR
and the RAP both suggest rainfall rates will start to diminish
after 12Z.

Bann

ATTN...WFO...HGX...SHV...

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

LAT...LON   32969270 32339268 30839533 30949573 31919497
            32839393