MESOSCALE PRECIPITATION DISCUSSION 0068
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
616 AM EST THU MAR 10 2016
 
AREAS AFFECTED...LA...ERN TX...SRN AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 101115Z - 101615Z
 
SUMMARY...FLASH FLOODING WAS ONGOING AND ADDITIONAL HEAVY RAIN
WILL EXACERBATE FLOODING IN FAR EAST TEXAS AND WESTERN AND
NORTHERN LOUISIANA. DEVELOPMENT OF HEAVY RAIN AND FLASH FLOODING
IS ALSO FORECAST INTO PARTS OF SOUTHERN LOUISIANA AND SOUTHWEST
MISSISSIPPI EARLY THIS MORNING.

DISCUSSION...A PROLIFIC RAIN AND FLASH FLOOD EVENT CONTINUED AT
11Z. DURING THE PAST 12 HOURS RADAR AND OBSERVATIONS INDICATED 5
TO 10 INCHES OF RAIN HAD FALLEN FROM NEAR BEAUMONT TX TO JUST WEST
AND NORTH OF ALEXANDRIA LA UP TO NEAR EL DORADO ARKANSAS. A
SURFACE FRONT REMAINED STALLED JUST SOUTH OF THAT LINE...WITH
STRONG LOW LEVEL FLOW RESISTING THE PUSH OF CONVECTIVE
OUTFLOWS...OUTFLOWS THAT WERE INHERENTLY WEAK GIVEN DEEPLY
SATURATED PROFILES. ASCENT WILL ACTUALLY INCREASE THIS MORNING
OWING TO DIFLUENT UPPER FLOW AND AN APPROACHING S-N ORIENTED JET
STREAK ON THE EAST SIDE OF THE BROAD UPPER LOW...AS WAS ALREADY
EVIDENCED BY COOLING CLOUD TOPS PER IR IMAGERY AND THE INCREASE OF
STRONG AND DEEP CONVECTION PER RADAR LOOPS OVER SE TX/SW LA AND
OFFSHORE WATERS. THOUGH THE OBSERVATIONS PAINT A CLEAR
PICTURE...MODEL QPFS WERE NOT HANDLING THE DETAILS. THE BEST
APPROXIMATION OF LATEST THINKING WOULD BE TO BLEND THE WPC
FORECAST WITH THE 08Z RAP.

MEAN FLOW WILL CARRY STORMS NORTHWARD... AND LITTLE CHANGE IN MEAN
FLOW AND/OR CORFIDI VECTORS IS EXPECTED TODAY. THOUGH RAINFALL
INTENSITY WILL TAPER OFF WITH NORTHWARD EXTENT...CELLS RIDING UP
OVER THE FRONT WILL DELIVER SUBSTANTIAL ADDITIONAL RAIN...1 TO 2.5
INCHES ON AVERAGE...TO THE SAME ARES WHICH RECEIVED 5 TO 10 INCHES
OVERNIGHT. FARTHER S AND E...MUCH MORE RAIN IS REQUIRED TO REACH
FLASH FLOOD GUIDANCE VALUES...BUT THE COMBINATION OF MODERATE CAPE
AND NEAR RECORD PW VALUES SHOULD SPELL INTENSE RAIN RATES NEAR
2"/HR. SOME UPPER LEVEL DRYING PER WATER VAPOR IMAGERY...AS WELL
AS SOME DECREASE TO LOW LEVEL FLOW LATER IN THE MORNING SHOULD
ENCOURAGE SOME PROPAGATION / EXPANSION TO THE EAST INTO SRN LA AND
SW MS...BUT WITH FLASH FLOODING BECOMING LIKELY IN THOSE AREAS
WHENEVER LOCAL EPISODES OF TRAINING OCCUR.

BURKE

ATTN...WFO...HGX...JAN...LCH...LIX...LZK...SHV...

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

LAT...LON   33329279 33299200 32649109 32019065 30689109 
            29369157 29039242 29409335 29809384 29969476 
            30599532 31929498 32449387