MESOSCALE PRECIPITATION DISCUSSION 0053
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1217 AM EDT TUE MAY 13 2014
 
AREAS AFFECTED...SOUTHEAST TX...SOUTHWEST LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 130410Z - 130800Z
 
SUMMARY...A SLOW-MOVING BAND OF INTENSE CONVECTION CONTINUES TO
ADVANCE GRADUALLY THROUGH SOUTHEAST TX AND SHOULD IMPACT PORTIONS
OF SOUTHWEST LA OVER THE NEXT FEW HOURS. HEAVY RAINFALL RATES OF 2
TO 3 INCHES/HR WILL CONTINUE AND WILL PROMOTE SHORT-TERM THREATS
OF FLASH FLOODING.

DISCUSSION...THE SWRN EXTENSION OF A LARGE WAVY QLCS IS SEEN
SLOWLY PUSHING SEWD THROUGH SERN TX ATTM AND IS APPROACHING SWRN
LA. PORTIONS THE LINE ARE NOTABLY SLOWER MOVING COMPARED TO OTHER
AREAS WHERE THERE IS MORE BOWING NOTED DUE TO THE EVOLUTION OF THE
COLD POOL BEHIND THE INITIAL CONVECTIVE LINE.

THE LATEST RAP ANALYSIS SHOWS MUCAPE VALUES ON THE ORDER OF 2000
TO 3000 J/KG POOLED ACROSS THE WRN GULF COAST REGION AND THE
SOUTHEAST TX COASTAL PLAIN. THIS COUPLED WITH A PERSISTENT AND
VERY MOIST LOW LVL SELY FETCH IN OFF THE GULF OF MEXICO SHOULD AT
LEAST MAINTAIN THE LEVEL OF ACTIVITY. THERE WILL BE A RISK TOO FOR
SOME ADDITIONAL MULTI-CELL CONVECTION TO PRECEED THE QLCS IN THE
WARM/MOIST UNSTABLE SECTOR AND FOSTER THE RISK FOR ADDITIONAL
CELL-MERGERS. AFTER 06Z...INCREASING LOW LVL CINH MY TEND TO ALLOW
THE QLCS TO STEADILY WEAKEN...BUT THERE IS SOME UNCERTAINTY ON HOW
QUICK THAT MAY HAPPEN. IN THE MEANTIME...INTENSE RAINFALL RATES
ARE EXPECTED...WHICH MAY BE AS HIGH AS 2 TO 3 INCHES/HR WITHING
THE HEAVIER CELLS.

EXPECT ADDITIONAL RISK FOR SHORT-TERM FLASH FLOODING OVER THE NEXT
FEW HOURS GIVEN THE SLOW MOVEMENT OF THE ACTIVITY AND INTENSE
RAINFALL RATES. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...LCH...SHV...HGX...FWD...CRP...EWX...

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

LAT...LON   30599630 30969544 31489448 32009343 31719240 30819225
            30119262 29429350 28769461 28099606 27659738 27409869
            27649971 27930009 28610026 29269986 29909885 30499794
            30599630