MESOSCALE PRECIPITATION DISCUSSION 0075
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
232 AM EST FRI MAR 11 2016
 
AREAS AFFECTED...N LOUISIANA...SE ARKANSAS...EXT W MISSISSIPPI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110731Z - 111131Z
 
SUMMARY...ELEVATED CONVECTION WITHIN TROWAL TO AFFECT AREAS HIGHLY
SATURATED GROUNDS TO EXACERBATE ONGOING FLASH FLOODING. 

DISCUSSION...RADAR MOSAIC AND SATELLITE IMAGERY INDICATE STRONG
CONVECTION DEVELOPED ALONG THE COLD FRONT JUST OFFSHORE OF SW LA. 
THOUGH THE MAIN CORES OF THE CONVECTION ARE ADVANCING EASTWARD
SLOWLY...THE WESTERN BRANCH OF THE STRENGTHENING WARM CONVEYOR
BELT IS PROVIDING ENOUGH MOISTURE/WEAK INSTABILITY TO SUPPORT
EMBEDDED CONVECTIVE ELEMENTS SHEARING BACK WESTWARD WITHIN THE
TROWAL. CELLS CONTINUE TO COOL TO -60C WITH INCREASING RAIN RATE
EFFICIENCY SEEN IN THE LCH RADAR.  BASES APPEAR TO BE BETWEEN
800-750 MB SUPPORTED BY INCREASING 40 TO 50 KT KT SLY FLOW THAT
WITH FAIRLY DEEP LOW LEVEL MOISTURE...WILL SUPPORT 1.5-2"/HR
RATES.  THE POSITIVE TO THIS TROWAL CONVECTION IS FAST MEAN FLOW
LIMITING OVERALL TOTALS...THE NEGATIVE IS TOTALS IN THE 1" RANGE
COULD BE SUFFICIENT TO EXCEED SHORT TERM FFG VALUES IN A LINE
NORTH OF VERNON TO CONCORDIA PARISH AND NORTHWARD TO EXT SE AR
LIKELY TO COMPOUND ONGOING FLOODING CONDITIONS IN THIS REGION.

AS THE FRONTAL ZONE CONVECTION THAT IS ROOTED IN THE BOUNDARY
LAYER SHIFTS NE TOWARD SE LA/S MS TOWARD 10Z...BEST ASCENT/FORCING
WILL DEMINISH FURTHER WEST LIMITING COVERAGE CLOSER TOWARD THE
MISSISSIPPI RIVER OVER NE LA/SW AR AND THE SW COUNTIES OF MS THAT
BORDER THE RIVER ITSELF.  HI-RES CAM GUIDANCE PARTICULARLY THE
LAST FEW RUNS OF THE HRRR AND 00Z NMMB SUPPORT THIS OVERALL
SCENARIO.   

GALLINA

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

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

LAT...LON   33659103 32849065 31869078 31529097 31069159 
            31079326 31699356 32579306 33179205