MESOSCALE PRECIPITATION DISCUSSION 0154
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
531 AM EDT SAT APR 30 2016
AREAS AFFECTED...SOUTHEAST TX...WESTERN AND CENTRAL LA...FAR
SOUTHERN AR
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 300931Z - 301400Z
SUMMARY...THE RISK OF FLASH FLOODING WILL CONTINUE OVER PORTIONS
OF TX/AR/LA GIVEN THE APPROACH OF THUNDERSTORMS SLOW MOVING
THUNDERSTORMS WHICH HAVE BEEN PRODUCING VERY INTENSE RAINFALL.
DISCUSSION...VERY HEAVY RAINFALL ASSOCIATED WITH A LINE OF SLOW
MOVING THUNDERSTORMS WILL CONTINUE TO MOVE SLOWLY EASTWARD FROM
SOUTHEAST TX ACROSS MUCH OF WESTERN AND PARTS OF CENTRAL LA BY MID
MORNING.
STRONG MOISTURE FLUX FROM THE GULF WILL CONTINUE TO FUEL RAINFALL
RATES OF UP TO 2.5 INCHES PER HOUR. WITH MLCAPE RUNNING SOME 2500
J PER KG UPSTREAM OF THE CONVECTION AND H85 FLOW FORECAST TO
CONTINUE AROUND 50 KTS...AND CLOUD TOP TEMPERATURES WHICH CONTINUE
TO COOL...THINKING IS THAT THE POTENTIAL FOR FLASH FLOODING WILL
CONTINUE INTO MID MORNING.
THE AREA DEFINED IN THE MPD WAS EXPANDED A BIT TOWARDS THE NORTH
AND EAST INTO NORTHEAST LA AND EXTREME SOUTHERN LA DUE TO SIGNAL
FOR THE POTENTIAL OF 2 INCHES IN ONE HOUR SHOWN BY THE HRRR TIME
LAGGED ENSEMBLE RUN FROM 07Z. OTHERWISE THE AREA WAS DRAWN BASED
ON TRANSLATION OF THE EXISTING THUNDERSTORMS AND FOR A SLIGHT
INCREASE IN FORWARD SPEED POSSIBLE AFTER 12Z. A SIMILAR IDEA FROM
OTHER CONVECTIVE ALLOWING MODELS FOSTERS INCREASE CONFIDENCE IN
THE SHORT TERM EVOLUTION OF HEAVY RAINFALL.
BANN
ATTN...WFO...HGX...JAN...LCH...LIX...SHV...
ATTN...RFC...LMRFC...WGRFC...
LAT...LON 33209160 31459126 29899152 29709275 29769342
29659408 29159502 29679564 30329555 31019449
32779317
Last Updated: 531 AM EDT SAT APR 30 2016