MESOSCALE PRECIPITATION DISCUSSION 0013
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 PM EDT SUN APR 06 2014
 
AREAS AFFECTED...ERN TX...SE AR...LA...MS...WRN AL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 061944Z - 070144Z
 
SUMMARY...FLASH FLOOD RISK IS GREATEST OVER SATURATED SOIL THROUGH
EVENING. HEAVY RAIN RATES CAPABLE OF MEETING FLASH FLOOD GUIDANCE
WILL ALSO EXPAND WITH TIME...ESPECIALLY TO THE NORTH.

DISCUSSION...THE 12Z HIGH RESOLUTION MODELS SHIFTED THEIR AXES OF
HEAVY QPF NORTHWARD INTO THE OUTLINED AREA...AND ARE SUPPORTED BY
THE LATEST HRRR RUNS. A NARROW SWATH OF THE AREA HAD ALREADY SEEN
2 TO 4 INCHES OF RAIN.

A GROWING MASS OF CONVECTION IN TX/LA AT 1930Z WAS LIKELY THE
BEGINNING OF A PROGRESSIVE MCS EVENT THAT WILL AFFECT ADJACENT AR
AND CENTRAL MS THROUGH 01Z. FLUX OF MOISTURE/INSTABILITY WILL ALSO
INCREASE DOWNSTREAM INTO AL WHERE EARLIER OUTFLOWS AND CONTINUED
MID LEVEL GRADIENTS MAY SUPPORT FORMATION OF ADDITIONAL MDT/HVY
DOWNPOURS BEFORE SYNOPTIC FORCING SHIFTS NORTH. IN LA THE
SITUATION SHOULD TRANSITION TOWARD ONE OF BACKBUILDING AND SW TO
NE TRAINING BY EVENING AS LOW LEVEL FLOW VEERS TO BECOME PARALLEL
WITH THE UPPER LEVELS. THIS SETUP WAS ALREADY EVIDENT WITH THE
FLOODING REPORTS NEAR TYLER TX WHERE VEERING HAD BEGUN.

MODELS FEATURE ROBUST PRECIP TOTALS...WITH ANOTHER 1-3 INCHES ON
AVERAGE THROUGH MID EVENING...AND SOME SUGGESTION BY THE WRF-ARW
OF LOCAL 4-6 INCH TOTALS FOR THE AFTERNOON/OVERNIGHT EVENT ALONE.
THIS WOULD BE ESPECIALLY CONCERNING FOR THE SATURATED SWATH FROM
NE LA TO NEAR JACKSON MS WHERE THE MODEL QPFS ARE UNANIMOUSLY
HEAVY.

BURKE

ATTN...WFO...BMX...MOB...MEG...JAN...LZK...SHV...

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

LAT...LON   32899454 32569521 32149530 31719497 31349392 31759202
            31819123 31819001 31698891 31638765 31778723 32068717
            32548747 32948829 33478882 33929000 33169212 32969382
            32899454