MESOSCALE PRECIPITATION DISCUSSION 0048
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1043 AM EDT SUN MAY 19 2013
 
AREAS AFFECTED...CENTRAL/WESTERN GA...FAR SOUTHERN TN...FAR
EASTERN AL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 191334Z - 191845Z
 
SUMMARY...THUNDERSTORMS WITH EFFICIENT RAINFALL PRODUCTION
EXPECTED TO DRIFT SOUTHWARD ACROSS MAINLY WESTERN & CENTRAL
GEORGIA. DEVELOPMENT OF NEW FLASH FLOOD AREAS IS POSSIBLE.

DISCUSSION...AN ORGANIZED HEAVY RAIN EVENT HAD ALREADY BEEN IN
PROGRESS FOR SEVERAL HOURS WITH MOST RECENT THUNDERSTORM
ENHANCEMENT OVER NORTHWEST GEORGIA. CLUSTERS OF STORMS WERE
OBSERVED ALONG/NEAR A 850-MB BAROCLINIC ZONE FROM SOUTHERN KY
THROUGH TN AND GA. A RESERVOIR OF POTENTIALLY UNSTABLE AIR WAS IN
PLACE WEST OF THIS ZONE...AND WAS FEEDING INTO THE ONGOING STORMS.
THE ACTIVITY IN GA WAS THE MOST ORGANIZED OWING TO ENHANCED LOW
LEVEL INFLOW AND MID LEVEL ASCENT IN ADVANCE OF A SUBTLE 500-250
MB SHORTWAVE TROUGH PER THE GLOBAL AND HIRES MODELS. FORECASTS OF
THE LOW AND MID LEVEL FLOW REGIME FROM THE GFS/RAP/HRRR SUGGEST
LITTLE CHANGE IN THE ENVIRONMENT UNTIL EITHER THE COLD POOLS GROW
UPSCALE TO FORCE QUICKER PROGRESSION TOWARD THE SSE...OR THE
MID/UPPER LEVEL WAVE PROGRESSES TOWARD SOUTHEAST GA AND THE
CAROLINAS BY THIS AFTERNOON. 

UNTIL THEN...EXPECT CONTINUATION OF NNW TO SSE TRAINING CELLS WITH
VERY EFFICIENT RAINFALL PRODUCTION. 12Z FFC RAOB NEARLY HALF THE
CAPE BENEATH THE FREEZING LEVEL AND RADAR DATA INDICATED DEEP
UPDRAFTS DOMINATED BY HEAVY RAIN RATHER THAN HAIL. PER NESDIS
SPENES MESSAGE...AREAL AVERAGE 1-3 INCH RAINS
LIKELY...PARTICULARLY OVER WESTERN AND CENTRAL GEORGIA...BUT LOCAL
AMOUNTS OVER 3-4 INCHES ARE POSSIBLE THROUGH 19Z WHEREVER CELL
MERGERS TAKE PLACE. IT IS THOUGHT TO BE LESS LIKELY THAT HEAVY
RAIN WOULD BE ABLE TO MOVE BACK INTO THE AREAS OVERTURNED BY
PERSISTENT CONVECTION EARLIER IN THE MORNING.

BURKE


ATTN...WFO...CHS...JAX...FFC...TAE...BMX...HUN...

LAT...LON   33808355 33318286 32758232 32268211 31658230 31568298
            31708411 32158479 33038529 33928561 34868582 34898451
            34668427 34118387 33808355