MESOSCALE PRECIPITATION DISCUSSION 0060
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 PM EDT WED MAY 14 2014
 
AREAS AFFECTED...NORTHERN FL...MOST OF AL...WESTERN GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 141957Z - 150157Z
 
SUMMARY...A PAIR OF SURFACE TROUGHS AND AN ADVANCING COLD FRONT
ARE EXPECTED TO ACT AS FOCI FOR HEAVY RAINFALL OVER THE NEXT
SEVERAL HOURS.  REGIONAL FLASH FLOODING IS CONSIDERED POSSIBLE.

DISCUSSION...AN OUTFLOW BOUNDARY AHEAD OF A COLD FRONT MOVING
ACROSS SOUTHEAST LA IS JOINING FORCES WITH A TROUGH ACROSS
SOUTHWEST GA AND NORTHERN FL CAUSED BY SEA BREEZE CONVERGENCE,
FOCUSING TWO BANDS OF CONVECTION.  THUNDERSTORMS HAVE FORMED ALONG
A THIRD BAND ASSOCIATED WITH THE COLD FRONT MOVING ACROSS MS. 
HOURLY RAINFALL RATES OF 2" ARE COMMON WITHIN STRONGER STORMS
WITHIN THE CONVERGENCE BANDS.  PRECIPITABLE WATER VALUES REMAIN IN
THE 1.75-2" RANGE, ABOVE THE 90TH PERCENTILE FOR MID-MAY.  THE
STORMS ARE TAPPING CAPES OF 2000 J/KG AND 0-3 KM WIND SHEAR IN THE
REGION OF 25+ KTS CONTINUES, YIELDING ORGANIZED MULTI-CELLULAR
CLUSTERS.

THE MESOSCALE GUIDANCE IS NEARLY UNANIMOUS THAT THESE TWO
THUNDERSTORM BANDS WILL YIELD HEAVY RAINFALL OVER THE NEXT SEVERAL
HOURS, ADVANCING NORTHWARD THROUGH EASTERN AL AND WESTERN GA WITH
TIME, AND SHOWING LOCAL MAXIMA OF 3-6" FALLING WITHIN SEVERAL
HOURS.  STRONGER CLUSTERS OF STORMS SHOULD CONTINUE TO PRODUCE 2"
PER HOUR RAINFALL RATES UNTIL 00Z, WHEN ACTIVITY SHOULD SLOWLY
DECREASE IN COVERAGE AND INTENSITY AS CAPE VALUES DECREASE, PER
THE 12Z ARW MASS FIELDS.  LOCAL RAINFALL AMOUNTS OF 3-6" COULD
LEAD TO REGIONAL FLASH FLOODING, DESPITE THE HIGH FLASH FLOOD
GUIDANCE SEEN ACROSS THE AREA.    

ROTH

ATTN...WFO...TBW...JAX...FFC...TAE...BMX...HUN...MOB...

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

LAT...LON   28988247 29988342 31448482 30408601 30328692 30158812
            30648829 32408779 34288689 34508455 32058307 29368230
            28988247