MESOSCALE PRECIPITATION DISCUSSION 0152
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
625 PM EDT TUE JUL 09 2013
 
AREAS AFFECTED...CENTRAL IN INTO MUCH OF OH/WV AND SWRN PA/NRN KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 092224Z - 100424Z
 
SUMMARY...EXTREMELY LOW FLASH FLOOD GUIDANCE ACROSS OH INTO WV AND
SWRN PA. LEADING BAND OF SHOWERS/STORMS ALLOWING AN ANOMALOUS
PLUME OF LOW LEVEL MOISTURE TO ARRIVE INTO THE OH VLY... WELL
AHEAD OF AN UPSTREAM SHORT WAVE TROUGH. MORE CELLS DEVELOPING FOR
POSSIBLE TRAINING AND FLASH FLOOD THREAT.

DISCUSSION...WATER VAPOR IMAGERY THIS AFTN SHOWS A WELL DEFINED
VORT LOBE AND MID-LEVEL CIRCULATION MOVING THROUGH THE UPPER
MIDWEST. THIS IS IN ASSOCIATION WITH A PROGRESSIVE SHORT WAVE
TROUGH. WELL AHEAD OF THE IMPULSE IS A LEADING AREA OF
SHOWERS/STORMS MOVING THROUGH LOWER MI AND MUCH OF OH... BASICALLY
A WARM FRONTAL DEWPOINT/MOISTURE BOUNDARY. THIS IS ALLOWING A
SURGE OF 2 INCH PLUS PWS TO POOL FROM IL/IN AND GRADUALLY SPREAD
INTO OH/KY/WV AND WRN PA. THERE APPEARS TO BE ENOUGH INSTABILITY
AND HEATING AHEAD OF THE VORT LOBE FOR ADDITIONAL CONVECTIVE HEAVY
RAIN CELLS TO DEVELOP... POSSIBLY ORGANIZE AND TRAIN OVER AN AREA
WITH EXTREMELY LOW FFG. THE 1 HR FFG ACROSS MUCH OF OH INTO SWRN
PA AND NRN WV IS HOVERING AROUND .50 TO .75 INCHES AND ADD IN SOME
HILLS/TERRAIN... IT WILL NOT TAKE MUCH FOR MORE FLOODING. THE
INTIAL BATCH OF STORMS IS ALREADY PRODUCING DECENT RAIN RATES WITH
A FEW LOCALIZED WARNINGS BUT THE REAL THREAT IS POSSIBLY ON THE
HORIZON. THE 12Z HI-RES ARW AND NMM PINPOINT A MAX AREA OF
VERTICAL VELOCITIES WITH PRIME UPPER DIFLUENT FLOW FOR AN
ORGANIZED AREA OF HEAVY RAINFALL FROM IN INTO OH/NRN KY AND SPREAD
DOWNSTREAM. AS A RESULT OF ALL OF THIS... WPC WILL GO WITH A
RATHER LARGE THREAT AREA FOR THE NEXT SEVERAL HRS.  

MUSHER

ATTN...WFO...CTP...LWX...PBZ...RLX...CLE...JKL...ILN...LMK...
IWX...IND...

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

LAT...LON   38928587 39328695 40398659 41078413 41288187 40587989
            39937889 38737954 38118188 38448466 38928587