MESOSCALE PRECIPITATION DISCUSSION 0043
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1055 AM EDT SAT MAY 18 2013
 
AREAS AFFECTED...NORTHERN AND EASTERN AL...EXTREME WESTERN GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 181454Z - 182054Z
 
SUMMARY...ADDITIONAL SLOW MOVING AND REPEAT CONVECTION IS EXPECTED
OVER THE NEXT SEVERAL HOURS ACROSS PORTIONS OF NORTHERN AND
EASTERN AL AND EXTREME WESTERN GA WITH INTENSE RAINFALL RATES.

DISCUSSION...ALTHOUGH CONVECTION THROUGH THE MORNING HOURS HAS
TENDED TO WEAKEN AND HAS BECOME RELATIVELY DISORGANIZED...WITH
CLOUD TOPS ALSO TENDING TO WARM...ADDITIONAL CONVECTIVE CELLS
CONTINUE TO DEVELOP INVOF AND TO THE NORTH OF A CONVECTIVELY
REINFORCED BOUNDARY. THE MORNING CONVECTION HAS AFFORDED A
SUFFICIENT COLD POOL SUCH THAT LARGER SCALE MOIST AND UNSTABLE
SOUTHWESTELY FLOW INTERSECTING AND OVERRUNNING THIS AIRMASS
CONTINUES TO FOSTER REPEAT CONVECTIVE DEVELOPMENT. THE LARGER
SCALE CONVECTIVE CLUSTER IS TENDING TO BOW SOUTHEASTWARD AND AWAY
AREAS HIT EARLY THIS MORNING WITH TRAINING CONVECTION...BUT LATEST
VIS IMAGERY SUGGESTS A GRADUALLY EXPANDING CU FIELD OVER SOUTHERN
MS AND SOUTHERN AL. INCREASED DIURNAL HEATING AND ASSOCIATED
SFC-BASED INSTABILITY SHOULD CONTINUE TO ADVECT OVERTOP THE COLD
POOL THE NEXT FEW HOURS AND SUPPORT ADDITIONAL CONVECTIVE
DEVELOPMENT...ALSO FARTHER BACK TO THE NORTHWEST INTO
NORTH-CENTRAL AL. THE SLOW MOVEMENT OF THE CONVECTION AND TENDENCY
FOR TRAINING WILL SUPPORT ADDITIONAL HEAVY RAINFALL AMOUNTS...WITH
RATES OF 1 TO 2 INCHES/HR. ADDITIONAL FLASH FLOODING WILL BE
POSSIBLE AS A RESULT.

ORRISON


ATTN...WFO...FFC...TAE...BMX...HUN...

LAT...LON   32848443 32368436 31958432 31708463 31658507 31918554
            32078573 32508612 33058644 33488689 33978787 34458809
            34738776 34578667 34018539 33658493 33298469 32848443