MESOSCALE PRECIPITATION DISCUSSION 0645
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EDT MON AUG 07 2017

AREAS AFFECTED...SOUTHEAST TX...SOUTHWEST LA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 071755Z - 072200Z

SUMMARY...VERY HEAVY SHOWERS AND THUNDERSTORMS MOVING THROUGH
SOUTHEAST TX AND PARTS OF SOUTHWEST LA WITH INTENSE RAINFALL RATES
OF UP TO 2.5 INCHES/HR. SOME FLASH FLOODING IS POSSIBLE.

DISCUSSION...THE LATEST RADAR IMAGERY SHOWS A BAND OF VERY HEAVY
SHOWERS AND THUNDERSTORMS MOVING ACROSS THE SOUTHEAST TX COASTAL
PLAIN WHICH WILL BE IMPACTING THE HOUSTON METROPOLITAN AREA OVER
THE NEXT COUPLE OF HOURS. THE ACTIVITY IS FOCUSING IN A VERY
MOIST/TROPICAL AIRMASS AND WITHIN A STRONG INSTABILITY GRADIENT
ALONG THE IMMEDIATE MIDDLE/UPPER TX COASTLINE.

OVER THE NEXT FEW HOURS...EXPECT VERY INTENSE RAINFALL RATES WITH
CONVECTION LIKELY BECOMING A BIT FURTHER ORGANIZED OUT AHEAD OF A
WEAK AREA OF LOW PRESSURE AND AN ASSOCIATED MCV OVER SOUTH-CENTRAL
TX. THE CONVECTION WILL LIFT NORTHEAST ACROSS SOUTHEAST TX AND
GRADUALLY GET INTO SOUTHWEST LA. THE RAINFALL RATES MAY REACH 2.5
INCHES/HR GIVEN PWATS OF 2.2 TO 2.4 INCHES WHICH WILL YIELD HIGHLY
EFFICIENT RAINFALL PROCESSES.

THE LATEST SATELLITE AND RADAR TRENDS SUPPORT AS MUCH AS 3 TO 5
INCHES OF RAIN LOCALLY THROUGH 22Z...AND CONSIDERING THE URBANIZED
ENVIRONMENT AND SUCH HEAVY RAINFALL RATES...FLASH FLOODING WILL BE
A CONCERN GOING THROUGH THE AFTERNOON HOURS.

ORRISON

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

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

LAT...LON   31729354 31219295 30289289 29909318 29769355
            29629424 29209478 28749564 28819603 29189600
            30569568 31249525 31699468