Mesoscale Precipitation Discussion 0941
NWS Weather Prediction Center College Park MD
300 AM EDT Mon Oct 08 2018

Areas affected...Rio Grande Valley to the TX Hill Country

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

Valid 080700Z - 081300Z

Summary...Extremely heavy rainfall from repeating showers and
thunderstorms will continue across the TX Hill Country going
through dawn. Additional flash flooding is likely.

Discussion...The latest satellite imagery continues to show a
strongly divergent flow pattern aloft within what is a very moist
and at least modestly unstable airmass across the middle and lower
Rio Grande Valley. MUCAPE values are running generally around 1500
j/kg and PWATS are as high as 1.8 to 2.0 inches.

Showers and thunderstorms with very cold convective tops have been
backbuilding and repeating over the same area with a focus on
Edwards and Real Counties. In fact, already parts of southwest
Real county have seen radar estimates closing in on 5 inches of
rain.

The latest hires model guidance including the 00Z ARW/NMMB
solution and the HRRR continue to favor an axis of enhanced
convection with very heavy rainfall continuing through 12Z.
Additional rainfall amounts of as much as 3 to 5 inches with
locally heavier amounts can be expected. Some of this rain may
fall on areas that have already seen heavy totals, and thus there
will be strong concerns for additional flash flooding going
through the dawn time-frame.

Orrison

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

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

LAT...LON   31330005 30959949 30119948 29649969 29440006
            29480067 29760103 30160120 30810120 31260082