MESOSCALE PRECIPITATION DISCUSSION 0259
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 PM EDT MON MAY 22 2017

AREAS AFFECTED...NORTHERN GA...NW SC

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 221814Z - 222230Z

SUMMARY...CONVECTIVE STORMS BECOMING MORE ORGANIZED ACROSS
NORTHERN GA INTO SC COULD PRODUCE HEAVY ENOUGH RAIN TO RESULT IN
LOCAL FLASH FLOODING.

DISCUSSION...RADAR IMAGERY SHOWS CONVECTIVE STORMS BECOMING MORE
ORGANIZED ACROSS NORTHERN GA INTO NORTHWEST SC ALONG A STATIONARY
FRONTAL BOUNDARY. PWATS IN THE REGION ARE GENERALLY 1.5-2.0" WITH
MUCAPE IN THE 1500-2500 J/KG RANGE. BULK SHEAR IS AROUND 30
KT...SUGGESTING THAT THE STORMS WILL CONTINUE TO BECOME MORE
ORGANIZED OVER THE NEXT FEW HOURS. 

THE REGION SHOULD CONTINUE TO SHIFT SLOWLY EAST-NORTHEAST ALONG
THE FRONTAL BOUNDARY FOR THE NEXT SEVERAL HOURS. CONTINUED HIGH
PWATS AND INSTABILITY...DAYTIME HEATING AND BULK SHEAR ALL
INDICATE THAT CONVECTION SHOULD INCREASE IN COVERAGE OVER THE AREA
AND BECOME MORE ORGANIZED. IN ADDITION A MINOR UPPER SHORTWAVE
APPROACHING FROM THE WEST SHOULD HELP INCREASE DIFFLUENCE ALOFT.

FFG VALUES ARE MAINLY 2-3" ACROSS THE THREAT AREA...WITH GENERALLY
LOWER VALUES TO THE NORTH AND HIGHER VALUES TO THE SOUTH. TOTAL
RAINFALL AMOUNTS SHOULD LOCALLY EXCEED THE 3-HOUR FFG VALUES.

HIRES MODELS DO NOT SEEM TO HAVE A GREAT DEPICTION OF THIS AREA OF
CONVECTION...BUT IN GENERAL THEY SUPPORT TOTAL RAINFALL AMOUNTS
LOCALLY EXCEEDING 3" DURING THE NEXT FEW HOURS.

MCDONNAL

ATTN...WFO...CAE...FFC...GSP...ILM...

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

LAT...LON   35078196 34758053 34357949 33678082 33748180
            33328303 33048401 33938450 34868329