MESOSCALE PRECIPITATION DISCUSSION 0015
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
121 AM EDT MON APR 07 2014
 
AREAS AFFECTED...SERN LA...CNTRL/SRN MS...CNTRL/NERN AL...NWRN GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 070520Z - 070930Z
 
SUMMARY...THE FLASH FLOOD THREAT CONTINUES ACROSS THE GULF COAST
STATES AS STRONG LINEAR BANDS OF CONVECTION CONTINUE TO TRAIN OVER
THE SAME AREA...INVOLVING ALREADY SATURATED SOIL.

DISCUSSION...THE LATEST IR/WV SATELLITE IMAGERY CONTINUES TO SHOW
VERY DIFFLUENT FLOW ALOFT OVER THE GULF COAST STATES OUT AHEAD OF
A STRONG SRN STREAM UPPER TROUGH THAT IS NOW MOVING INTO THE LOWER
MS VLY REGION. A VERY WELL-DEFINED SUBTROPICAL JET COUPLED WITH A
STRONG LOW LVL JET ON THE ORDER OF 50 TO 60 KTS IN OFF THE GULF OF
MEXICO AHEAD OF DEEPENING SFC LOW PRESSURE IS CONTRIBUTING TO
PWATS ON THE ORDER OF 1.6 TO 1.8 INCHES ACROSS CNTRL/SRN
LA...CNTRL/SRN MS AND CNTRL/SRN AL AS PER LATEST GOES-SOUNDER AND
GPS-DERIVED DATA. THIS COUPLED WITH A GRADUALLY NWD LIFTING WARM
FRONT IS CONTRIBUTING TO DEEP LAYER ASCENT AND A FAVORABLE SET-UP
FOR ORGANIZED AND VERY COLD-TOPPED CONVECTION WITH LINEAR BANDING
AND TRAINING ALONG WITH SEVERAL AREAS OF CELL-MERGERS. IN
FACT...THE LATEST GOES-EAST OTD ALGORITHM SHOWS NUMEROUS
OVERSHOOTING DETECTIONS OVER SERN LA AND SWRN MS LIFTING NEWD.
GIVEN THE NEARLY PARALLEL LOW/MID LVL FLOW RELATIVE TO THE ACTIVE
AREAS OF DEEP CONVECTION...A SIGNIFICANT THREAT OF TRAINING WILL
CONTINUE OVERNIGHT...AND THEREFORE AN ELEVATED RISK FOR ADDITIONAL
FLASH FLOODING.

THE LATEST HIRES GUIDANCE SUPPORTS THE IDEA OF CONTINUED SSW/NNE
ORIENTED CONVECTION AND POTENTIAL FOR TRAINING AND CELL-MERGERS.
RAINFALL RATES HAVE BEEN REPORTED TO BE OVER 2 INCHES/HR...AND
EXPECT NUMEROUS STORM TOTALS OF 4 TO 8 INCHES WITH SOME AREAS
POSSIBLY EXCEEDING 10 INCHES. THIS COULD RESULT IN
LIFE-THREATENING FLASH FLOODING CONCERNS. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...FFC...BMX...HUN...MOB...MEG...JAN...LIX...

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

LAT...LON   34048863 33439009 32459111 31349136 30349120 30029008
            30298932 31188799 31808644 32298508 32798416 33158381
            33718368 34468412 34778493 34638652 34048863