MESOSCALE PRECIPITATION DISCUSSION 0034
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
609 AM EDT TUE APR 29 2014
 
AREAS AFFECTED...FAR SOUTHEASTERN LA/EXTREME SOUTHERN AL/WESTERN
GA/FL PANHANDLE... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 291008Z - 291353Z
 
SUMMARY...CONVECTION IS CURRENTLY TRAINING ALONG THE SOUTHWESTERN
EXTENT OF A SQUALL LINE. DURING THE PAST FEW HOURS...THERE HAVE
ALREADY BEEN LOCAL REPORTS OF 3 TO 4 INCHES OF RAINFALL IN AN HOUR
ACROSS AREAS OF SOUTHEASTERN MS/SOUTHWESTERN AL. SUCH EXTREME
RATES WILL REMAIN POSSIBLE DURING THE NEXT COUPLE HOURS AS THE
CONVECTION CONTINUES TO BACKBUILD.

DISCUSSION...THE CURRENT RADAR IMAGERY DEPICTED A SQUALL LINE
ADVANCING INTO FAR WESTERN GA AND BACK ACROSS THE WESTERN FL
PANHANDLE AND JUST SOUTH OF THE MS/AL BORDER. THE NORTHERN EXTENT
OF THE LINE HAS SHOWN MORE EASTWARD MOVEMENT WHICH HAS LIMITED THE
THREAT FOR FLASH FLOODING. MEANWHILE...TO THE SOUTH...A COUPLE
MORE HOURS OF TRAINING THUNDERSTORM ACTIVITY IS POSSIBLE GIVEN THE
RADAR/SATELLITE TRENDS WHICH SHOW VERY SLOW STORM MOTIONS WITH NO
WEAKENING EVIDENT. IR SATELLITE IMAGERY CONTINUES TO INDICATE
CLOUD TOPS REACHING -80C WITH A VERY ACTIVE LIGHTNING SIGNATURE.

THE 09Z RAP SHOWED THERE IS STILL QUITE A BIT OF INSTABILITY ALONG
THE EASTERN GULF COAST WITH MUCAPE VALUES EXCEEDING 3000 J/K WITH
LITTLE TO NO INHIBITION SEEN. AS THE SQUALL LINE WILL BE
ENCOUNTERING THIS AIR MASS DURING THE NEXT HOUR OR TWO...THE
INTENSITY OF THE LINE SHOULD NOT CHANGE MUCH THROUGH 12Z. BEYOND
THIS PERIOD...HIGH-RESOLUTION GUIDANCE DOES SHOW GRADUAL WARMING
OF THE CLOUD TOPS AS THE LLJ STARTS TO WEAKEN. IN SPITE OF THE 1
AND 3-HOUR FFG VALUES BEING RATHER HIGH ACROSS THE FL
PANHANDLE...THE SYSTEM HAS ENOUGH HISTORY OF PRODUCING FLASH FLOOD
CONDITIONS TO KEEP THE THREAT IN PLACE.



RUBIN-OSTER

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

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

LAT...LON   33358370 32178350 31178372 30108429 29148575 29038753
            29168902 29528970 29928971 30278908 30428857 30548794
            30848708 31348639 32288574 33908542 34268452 34038405
            33358370