MESOSCALE PRECIPITATION DISCUSSION 0061...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
330 AM EDT WED MAY 22 2013
 
AREAS AFFECTED...FAR SOUTHEAST TX...SOUTHERN LA...SOUTHWEST MS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 220719Z - 221020Z
 
SUMMARY...TRAINING CONVECTION FROM THE GOLDEN TRIANGLE OF
SOUTHEAST TX THROUGH SOUTHERN LA INTO SOUTHWEST MS NEAR AND BEHIND
AN OUTFLOW BOUNDARY COULD LEAD TO FLASH FLOODING.

DISCUSSION...A SQUALL LINE/OUTFLOW BOUNDARY HAS SLOWED DOWN ITS
MOVEMENT AS IT HAS APPROACHED THE WESTERN GULF COAST ACROSS
SOUTHERN LA.  THE BEST 850 HPA INFLOW IS CONCENTRATED INTO THE
LOWER SABINE RIVER BASIN...WITH WIND SPEEDS OF 30-35 KNOTS MOVING
INTO THE REGION FROM THE GULF OF MEXICO AHEAD OF A SLOW-MOVING
COLD FRONT.  SOME CIN ALONG THE OUTFLOW BOUNDARY APPEARS TO BE
CAUSING CONVECTION TO BE ELEVATED ON ITS COLD/NORTH SIDE. 
CONVECTION CONTINUES BACK INTO SOUTHEAST TEXAS, BACKBUILDING
TOWARDS THE APPROACHING COLD FRONT AND MOVING EASTWARD WITH A
SLIGHT SOUTHERLY COMPONENT.  THIS INFLOW SHOULD REMAIN FIXED
ACROSS THE REGION FOR THE NEXT FEW HOURS WHICH WOULD CONTINUE
PRECIPITATION EFFICIENCY. PRECIPITABLE WATER VALUES -- PWS -- OF
1.75-2 INCHES RESIDE ACROSS THIS REGION, AND THERE IS SIGNIFICANT
DIVERGENCE ALOFT ON THE SOUTHEAST SIDE OF AN UPPER LEVEL LOW
MOVING ACROSS OK.  EVEN THOUGH FLASH FLOOD GUIDANCE VALUES -- FFGS
-- WERE HIGH AT 00Z, RECENT RAINFALL SHOULD HAVE DROPPED THESE
VALUES TOWARDS THE 3-4 INCH RANGE WITHIN 2-3 HOUR'S TIME, WHICH
WOULD BE POSSIBLE WITH A COUPLE MORE HOURS OF TRAINING.  THE SLOW
SOUTHWARD PROGRESSION EXPECTED WITH TIME ARGUED AGAINST USING
LIKELY WORDING.

ROTH


ATTN...WFO...JAN...LIX...LCH...HGX...

LAT...LON   31469008 31319171 30829377 30139530 29809493 29529340
            29749144 30369019 31128989 31469008