MESOSCALE PRECIPITATION DISCUSSION 0096
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
427 AM EDT MON APR 03 2017

AREAS AFFECTED...SOUTHEAST LA...SOUTHERN MS...COASTAL AL...EXT W
FL PANHANDLE

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 030830Z - 031300Z

SUMMARY...LINE OF HIGHLY EFFICIENT RAINFALL BECOMING PROGRESSIVE
INTO AREA OF MORE ACCEPTING GROUND CONDITIONS.  FLASH FLOODING
REMAINS POSSIBLE BUT MORE SCATTERED IN OCCURRENCE THROUGH EARLY
MORNING

DISCUSSION...GOES-E AND 16 WV INDICATES PVA/NVA COUPLET ARCING
FROM SE TX ACROSS LCH INTO THE CENTRAL GULF AROUND 92.5W  AS OF
0745Z...WITH BROADENING (NEARLY 90 DEGREES) DIFFLUENT FLOW ACROSS
SE LA/S MS INTO AL PROVIDING STRONG UPPER LEVEL EVACUATION AND
ASCENT...THIS WILL CONTINUE BUT AS THE TROF AXIS ADVANCES THIS
WILL SUPPORT A FAIRLY PROGRESSIVE NATURE TO THE BEST ASCENT AND
THEREFORE LINE OF CONVECTION.  STILL CELLS WITHIN THE LINE ARE
MOVING NORTHEAST EFFECTIVELY PARALLEL TO THE LINE ORIENTATION
SUPPORTING CELLS TO TRAIN AS THE LINE PROGRESSES SOUTHEAST.

IN THE LOWER LEVELS...AMPLE MOISTURE WITH SFC TDS IN THE LOW 70S
AND MODEST 7-8C/KM LAPSE RATES PER 05Z LIX RAOB PROVIDES WILL HELP
MAINTAIN SOLID UPDRAFTS AS WELL AS MST FLUX FOR EFFICIENT RAINFALL
PRODUCTION GIVEN MUCAPES OVER 1500 J/KG WITH VALUES AS HIGH AS
3000 J/KG (NEAR SURFACE BASED) ALONG THE GULF.  AS SUCH RADAR
ESTIMATES OF 2-2.5"/HR SEEM REASONABLE THOUGH FORWARD PROGRESSION
COULD LEAD TO 2.5-4" SWATH OF RAIN ACROSS SE LA WITH 2-3" FURTHER
NORTH ACROSS SE MS INTO SW AL.  THIS MATCHES RAINFALL TOTALS
THROUGH 15Z FROM BEST PERFORMING 00Z HI-RES CAMS IN THE ARW AND
NSSLWRF...THOUGH BOTH ARE SLIGHTLY SLOWER THAN CURRENT CONVECTIVE
TRENDS INDICATE. STILL WITH INCREASING FFG VALUES OF 3"/1HR TO
3.5-4"/3HRS...IT STILL MAY BE DIFFICULT FOR A LARGE AREA OF FF
CONDITIONS TO COME TO FRUITION AND THEREFORE THE RISK FOR FF IS
ONLY POSSIBLE AND LOCALIZED... PARTICULARLY IN URBAN AREAS.  

A STARK SFC TD GRADIENT EXISTS ACROSS FROM EET TO MGM TO 79J TO
MAI IN THE FL PANHANDLE AND DEMARCATES THE EASTWARD EXTENT OF
INSTABILITY AND ANY REAL THREAT FOR MAINTAINED CONVECTION THAT
WOULD POSE ANY FF RISK.

GALLINA

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...

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

LAT...LON   32438743 31748634 30658708 30268748 30058823
            29908864 29268888 28978907 29108975 29159095
            29919165 31029058 32338844