MESOSCALE PRECIPITATION DISCUSSION 0094...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
329 PM EDT SAT MAR 26 2016
 
AREAS AFFECTED...SOUTHEAST SC & VICINITY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 261928Z - 270028Z
 
SUMMARY...A CLUSTER OF THUNDERSTORMS IS INCREASING IN AREAL
COVERAGE AND INTENSITY.  HOURLY RAIN RATES UP TO 1.75", WITH LOCAL
AMOUNTS OF 3-5", COULD LEAD TO FLASH FLOODING.

DISCUSSION...A BAROCLINIC ZONE ACROSS EASTERN GA IS ACTING AS THE
FOCUS FOR OVERRUNNING THUNDERSTORM ACTIVITY, WHICH IS INCREASING
IN AREAL COVERAGE AND INTENSITY AS OF LATE.  PRECIPITABLE WATER
VALUES OF 1.5-1.6" INHABIT THE REGION PER GPS VALUES, WHILE
SOUTHWEST WINDS OF 25 KTS ARE OVERRIDING EAST-SOUTHEAST WINDS OF
5-10 KTS, CREATING 30-35 KTS OF CLOUD BASE INFLOW.  AN EARLIER
HOLE IN THE CLOUDINESS OVER SOUTHEAST GA HAS BULKED UP THE MLCAPES
IN THE WARM SECTOR TO 1000-2000 J/KG, WITH THE THUNDERSTORM
ACTIVITY FORMING AT THE CUSP OF THE INSTABILITY.  BULK SHEAR OF
30-40 KTS IS SEEN ACROSS THE REGION PER SPC MESOANALYSES, WHICH
SHOULD FURTHER ORGANIZE CONVECTION.  CELL MOTION HAS BEEN ROUGHLY
15 KTS TO THE NORTHEAST, WITH MORE ORGANIZED ACTIVITY CLOSER TO 30
KTS WITH A MORE EASTERLY COMPONENT, IN LINE WITH FORWARD
PROPAGATING CONVECTIVE VECTORS AND THE 1000-850 HPA THICKNESS
PATTERN.

THE CAM GUIDANCE IS UNANIMOUS IN ITS PORTRAYAL OF 3-5" LOCAL
AMOUNTS ACROSS SC OVER THE NEXT SEVERAL HOURS.  RAP GUIDANCE
SUGGESTS THE BOUNDARY IN EASTERN GA COULD LIFT NORTHEAST THROUGH
EASTERN SC WITH TIME, WHICH WOULD LEAD TO A NORTHEAST SHIFT TO THE
CONVECTIVE AREA.  A COMBINATION OF WEAKENING LOW-LEVEL INFLOW AND
WEAKENING INSTABILITY SHOULD CAUSE FOR SOME REDUCTION IN COVERAGE
AND INTENSITY TO THE ONGOING CONVECTION AFTER 22Z PER RAP
GUIDANCE, WITH THE GUIDANCE SUGGESTING A 00-01Z WINDOW FOR ITS
EVOLUTION INTO A STRATIFORM RAIN AREA.  UNTIL THEN, CELL MERGERS
WITH SOME SHORT PERIODS OF TRAINING ARE EXPECTED TO BE THE MAIN
HEAVY RAIN THREAT.  HOURLY RAIN RATES UP TO 1.75" COULD LEAD TO
FLASH FLOODING, PARTICULARLY WITHIN URBAN AREAS.

ROTH

ATTN...WFO...CAE...CHS...FFC...ILM...RAH...

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

LAT...LON   34797968 34467911 33887853 33617888 33077918 
            32488009 32168060 32098072 32168142 32348184 
            32878246 33688184 34428060