Mesoscale Precipitation Discussion 0991
NWS Weather Prediction Center College Park MD
434 PM EDT Fri Oct 19 2018

Areas affected...Texas Gulf Coast

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

Valid 192033Z - 200000Z

Summary...Moderate to locally heavy rain moving onshore will have
the potential to bring 1-2" hourly totals. Localized higher
amounts are possible in any training storms which could result in
flash flooding.

Discussion...Surface analysis shows coastal front has now shifted
just onshore the Texas Gulf Coast. This is also evident by the
increase in surface-based instability which is now progged to be
between 1500-2000 J/kg per recent RAP mesoanalysis. With peak
heating, thunderstorms have blossomed between CRP and HGX with
some hourly rates between 1-2" noted.

The environment is expected to remain supportive of heavy rain
over the next several hours. RAP moist BL convergence shows
increasing values through 00z in an anomalous moist airmass (PWATS
2-3 SD above the mean). With the flow expected to remain
convergent through late afternoon or early evening, there's the
potential for a few bands of training convection which could bring
totals above FFG values (which is the main limiting factor for
flash flooding at this point).

As a result, some localized flash flooding is possible,
particularly over any urban or poor drainage areas.

Taylor

ATTN...WFO...CRP...HGX...

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

LAT...LON   29789602 29459546 28849540 28169652 27539722
            28239768 29179655