MESOSCALE PRECIPITATION DISCUSSION 0437
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
858 PM EST TUE DEC 23 2014
 
AREAS AFFECTED...FAR SERN MS...SRN AL...WRN GA AND THE WRN FL
PANHANDLE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 240157Z - 240757Z
 
SUMMARY...AN AREA OF TRAINING CONVECTION APPEARS LIKELY TO FOCUS
OVER PORTIONS OF THE CNTRL TO ERN GULF COAST INTO SRN ALABAMA AND
POSSIBLY WRN GEORGIA THROUGH 07Z. RAINFALL RATES OF 1-2 IN/HR OVER
THE SAME LOCATIONS MAY LEAD TO FLASH FLOODING.

DISCUSSION...THE LEADING EDGE OF THE GREATEST LOW LEVEL
MOISTURE...MARKED BY DEWPOINTS IN THE LOW TO MID 70S...WAS
SITUATED ALONG AND JUST SOUTH OF THE GULF COAST AT 01Z. 850-700 MB
FLOW OF 50 TO 60 KTS FROM THE SSW CONTINUES TO OVERRUN THIS
BOUNDARY WITH NUMEROUS SHOWERS ORIENTED FROM SSW-NNE LOCATED TO
ITS NORTH...AS WELL AS A PROGRESSIVE SQUALL LINE OBSERVED ACROSS
ERN ALABAMA PRESSING EAST AT AROUND 35 KTS. 00Z RAOBS FROM LIX AND
TAE INDICATE PRECIPITABLE WATER VALUES THAT ARE 2-3 STANDARD
DEVIATIONS ABOVE THE MEAN...OUT AHEAD OF A COLD FRONT ANALYZED
ACROSS THE CNTRL GULF COAST...HELPING TO SUPPORT HOURLY RATES OF
1-2 IN/HR. 

AS THE SRN PORTION OF A LONGWAVE TROUGH OVER THE SRN PLAINS SLOWLY
EDGES EWD OVERNIGHT...THE FOCUS OF LOW LEVEL MOISTURE IS EXPECTED
TO REMAIN AIMED ACROSS THE CNTRL GULF COAST WITH CONTINUED
REGENERATION OF SHOWERS FROM THE SOUTH INTO THE WRN FL PANHANDLE
AND SRN ALABAMA. LOCATIONS FARTHER NORTH ACROSS CNTRL ALABAMA INTO
GEORGIA APPEAR TO BE LESS OF A THREAT GIVEN THE PROGRESSIVE NATURE
OF THE SQUALL LINE...BUT STEADY STRATIFORM RAINS BEHIND THE LINE
COULD CAUSE A FEW FLASH FLOOD PROBLEMS GIVEN RELATIVELY STEEP
850-500 MB LAPSE RATES REMAIN WITH WEAK ELEVATED INSTABILITY AND
UNIDIRECTIONAL FLOW. 

HI-RES MODELS SHOW VARYING SOLUTIONS WITH THE DETAILS WHICH LOWERS
CONFIDENCE...BUT THE 12Z ARW CONTINUES TO APPEAR TO HAVE THE BEST
HANDLE ON THE ONGOING SITUATION WITH 3-5 INCHES EXPECTED BY 08Z.

OTTO

ATTN...WFO...BMX...FFC...LIX...MOB...TAE...

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

LAT...LON   33178473 32398409 31418455 30048624 29748706 
            29728775 30048856 30608872 31368827 32798627