Mesoscale Precipitation Discussion 0982
NWS Weather Prediction Center College Park MD
717 PM EDT Mon Oct 15 2018

Areas affected...TX Hill Country

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

Valid 152315Z - 160500Z

Summary...Additional showers and thunderstorms this evening may
result in some flash flooding given wet antecedent conditions.

Discussion...The latest GOES-16 IR satellite imagery has been
showing some additional cooling of cloud tops across the Rio
Grande Valley and toward the TX Hill Country as stronger
right-entrance region jet dynamics arriving across the region
interact with a nose of elevated instability. The heavier shower
activity has been tending to focus within an axis of MUCAPE values
that are between 500 and 1000 j/kg, and with PWATS of 1.5 to 1.7
inches which is fostering enhanced rainfall rates.

Some weak embedded shortwave energy crossing the TX Big Bend
within the deep layer southwest flow ahead of an upper trough
amplifying over the Southwest U.S. may tend to enhance the
rainfall a bit further over the next several hours as it
approaches the TX Hill Country.

The latest hires model guidance favors some additional rainfall
amounts through the evening hours of as much as 2 to 4 inches with
isolated heavier amounts. Many areas of the TX Hill Country have
already seen plenty of heavy rainfall recently, and soil
conditions are very moist if not saturated. The additional
rainfall through the evening may result in some increased runoff
concerns and possible flash flooding.

Orrison

ATTN...WFO...EWX...FWD...SJT...

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

LAT...LON   31719914 31689827 30719841 30569849 29719895
            29399998 29570062 30030095 30390089 31100027