MESOSCALE PRECIPITATION DISCUSSION 0343
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 AM EDT THU JUN 21 2018

AREAS AFFECTED...SOUTH TEXAS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 210605Z - 211205Z

SUMMARY...ADDITIONAL CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS
WILL MAINTAIN A THREAT FOR FLASH FLOODING EARLY THIS MORNING.

DISCUSSION...AN MCV OVER SOUTH TEXAS IS QUASI-STATIONARY AT THIS
TIME...BUT SHOULD BEGIN TO SLOWLY ADVANCE WEST-SOUTHWEST OVER THE
NEXT SEVERAL HOURS. HEAVY SHOWERS AND THUNDERSTORMS CONTINUE TO
DEVELOP NEAR THE VORT CENTER AND ALSO AROUND THE SOUTHERN AND
EASTERN FLANKS OF IT WHERE A WELL-DEFINED AND STRONG INSTABILITY
GRADIENT IS NOTED. IN FACT...THE LATEST GOES-16 CLEAN IR SATELLITE
IMAGERY HAS BEEN SHOWING SOME COOLING CONVECTIVE TOPS AND
SUGGESTIVE OF A SLIGHT UPTICK IN CONVECTIVE ORGANIZATION.

VERY HIGH PWATS OF ABOUT 2.5 INCHES REMAIN IN PLACE ACROSS THE
REGION WHICH IS INDICATIVE OF A DEEP TROPICAL AIRMASS. THIS WILL
CONTINUE TO FAVOR ENHANCED RAINFALL RATES GIVEN THE HIGHLY
EFFICIENT RAINFALL PROCESSES THAT ARE IN PLACE.

SEVERAL CONVECTIVE BANDS ARE LIKELY TO IMPACT FAR SOUTH TX THROUGH
THE EARLY MORNING HOURS WITH MORE FOCUSED CONVECTION ALSO
PERSISTING NEAR THE VORT CENTER. THIS WILL FOSTER ADDITIONAL HEAVY
RAINFALL TOTALS THAT MAY LOCALLY BE AS MUCH AS 3 TO 5 INCHES.

GIVEN THE WET ANTECEDENT CONDITIONS...THE ADDITIONAL RAINFALL
AMOUNTS WILL LIKELY CAUSE SOME FLASH FLOODING.

ORRISON

ATTN...WFO...BRO...CRP...

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

LAT...LON   27829808 27749737 27059732 26599724 26069716
            25879743 25989800 26049838 26239873 26279881
            26359899 26529927 26859924 27399877