MESOSCALE PRECIPITATION DISCUSSION 0352
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
451 PM EDT TUE JUL 14 2015
 
AREAS AFFECTED......SOUTHWEST PA...WESTERN MD...WEST
VIRGINIA...EASTERN KY...SOUTHWEST VA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 142050Z - 150250Z
 
SUMMARY...TRAINING CONVECTION CAPABLE OF HOURLY RAIN RATES UP TO
2" AN HOUR COULD CAUSE FLASH FLOODING OVER AREAS WHERE PRIOR
SHOWERS/STORMS OCCURRED.

DISCUSSION...A MID LEVEL CIRCULATION CROSSING FROM EASTERN OHIO
MOVING EAST TOWARDS WESTERN PA HAS AN ASSOCIATED UPPER
DIVERGENCE/LOWER CONVERGENCE MAXIMA FORECAST TO MOVE IN ADVANCE OF
THE CIRCULATION ACROSS
SOUTHWEST PA...WESTERN MD...WV...EASTERN KY...AND ADJACENT
PORTIONS OF WESTERN VA. 

THESE AREAS EXPERIENCED PRIOR SHOWERS THAT HAVE RESULTED IN
LOWERED 6 HOUR FLASH FLOOD GUIDANCE VALUES TO AN INCH IN MUCH OF
THE RISK AREA. 

A PRIMARY BAND OF SHOWERS/STORMS HAS FORMED AND IS MOVING EAST
SOUTHEAST FROM OHIO INTO WV AND NORTHEAST KY.  MLCAPES IN THE
REGION CURRENTLY ARE 2-3000 J/KG, WHICH SHOULD CONTINUE TO SUPPORT
DEVELOPMENT. 
AREA FORECAST SOUNDINGS SHOW GRADUAL VEERING OF WINDS FROM WEST TO
WEST NORTHWEST...SO EAST SOUTHEAST MOTION SHOULD CONTINUE OVER
TIME. PRECIPITABLE WATER VALUES OF 1.5-1.75" EXIST HERE, 1.5-2
SIGMAS ABOVE THE MEAN FOR MID-JULY.

WITH LOW DIRECTIONAL SHEAR WITH HEIGHT, LOCALIZED TRAINING OF
CELLS IS EXPECTED.  FLASH FLOODING IS POSSIBLE WHERE CELLS TRAIN.
MODEL GUIDANCE SHOWS WIDESPREAD HALF TO ONE INCH RAINS WITH LOCAL
2-3 INCH AMOUNTS WHERE TRAINING OCCURS.

PETERSEN

ATTN...WFO...CTP...ILN...JKL...LMK...LWX...MRX...PBZ...RLX...
RNK...

ATTN...RFC...MARFC...OHRFC...

LAT...LON   40897791 39857758 37708052 36548450 37858503 
            38328353 38838171 40237987 40787932