MESOSCALE PRECIPITATION DISCUSSION 0111
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
342 PM EDT MON APR 11 2016
 
AREAS AFFECTED...S ARKANSAS...N LOUISIANA...C MISSISSIPPI...W
ALABAMA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 111945Z - 120000Z
 
SUMMARY...INCREASING CONVECTION COVERAGE/INTENSITY AND RAINFALL
EFFICIENCY IN THE NEXT FEW HOURS WITHIN POTENTIAL TRAINING AND/OR
REPEAT TRACKS CONTINUES FLASH FLOOD THREAT

DISCUSSION...AN ELONGATED QLCS WITH EMBEDDED ARCS/WEAK BOWS
EXTENDS FROM NW AL ACROSS N MS INTO S AR...WITH THESE BOWED
SEGMENTS SUPPORT SOME GENERAL TRAINING AT THE INTERSECTIONS NEAR
AND EAST OF PIVOT POINTS ALONG THE LINE AS IT SLOWLY PROPAGATES
SOUTH WITH FAIRLY STRONG EASTWARD CELL MOTIONS THROUGHOUT THE
COMPLEXES.  DEEP NEARLY UNIDIRECTIONAL 850-500 CLOUD BARING LAYER
ANALYSIS SHOWS A WEAK JET STREAK ACROSS N LA INTO A GENERAL MINIMA
IN CONVECTION ACROSS N CENTRAL MS.  18Z SHV/LCH  SOUNDINGS
INDICATES 2000+ J/KG WITH AMPLE MOISTURE...WITH VALUES OF
1.5-1.75" ACROSS MUCH OF LA INTO MS.  THIS HAS SUPPORTED
ADDITIONAL PRE QLCS CONVECTIVE DEVELOPMENT WITH EFFICIENT RAINFALL
PRODUCTION WITH RATES UP TO 1.5-2.0" PRECEDING THE QCLS WITH
SIMILAR RATES.   500-1000 THICKNESS ANALYSIS ALSO SHOWS A SLIGHTLY
DIVERGENT PACKING SUPPORTING WEAKENING C-VECTORS ACROSS S AR/N MS
WHILE ALSO SUPPORTING THE NORTHERN PORTION OF THE QLCS TO DESCEND
SOUTHWARD ALLOWING FOR A BETTER E-W ORIENTATION OF THE LINE ACROSS
S AR/CENTRAL MS TO W AL OVER THE NEXT 3-4 HOURS ALIGNED WITH CELL
MOTIONS SUPPORTING TRAINING PROFILE.   RECENT HRRR APPEAR TO BE
BEST INITIALIZED WITH ONGOING CONVECTION AND SUPPORT THIS IDEA
WITH A SWATH OF 3-5" TOTALS BY 00-01Z WHICH SEEMS REASONABLE
THOUGH GIVEN PRE-CONVECTIVE CELLS...MERGERS MAY LOCALLY INCREASE
TOTALS AND FURTHER COMPOUND FLASH FLOODING THREAT.  THOUGHT THE
HRRR MAY BE A BIT TOO DRY INITIALLY AS IT IS APT TO DO IN INITIAL
SPIN UP OF THE MODEL.

GALLINA

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

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

LAT...LON   34448969 34268667 33058694 32388904 32349092 
            32749318 33539318 33919118