MESOSCALE PRECIPITATION DISCUSSION 0358
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
849 PM EDT THU JUN 16 2016
 
AREAS AFFECTED...WESTERN PA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 170048Z - 170330Z
 
SUMMARY...CONVECTION WHICH HAS DEVELOPED IN A BROADLY DIFLUENT
REGION AHEAD OF A MID/UPPER LEVEL LOW WILL BE ROTATING INTO A
REGION OF LOW FLASH FLOOD GUIDANCE THROUGH 0330Z.

DISCUSSION...SHOWERS AND THUNDERSTORMS HAVE BEEN DEVELOPING OVER
PORTIONS OF NORTHWEST PA IN A REGION OF BROADLY DIFLUENT MID/UPPER
LEVEL FLOW.  LOW LEVEL FLOW SHOULD BE PULLING THE SHOWERS AND
THUNDERSTORMS SOUTHWARD OVER A REGION WHICH HAD RECEIVED SEVERAL
ROUNDS OF MODERATE TO HEAVY RAINFALL OVER THE PAST COUPLE OF DAYS.
 AS A RESULT...1- AND 3-HOURLY FLASH FLOOD GUIDANCE VALUES ARE
LESS THAN AN INCH.  FLASH FLOOD GUIDANCE VALUES FROM 18Z SHOWED
VALUES AS LOW AS 0.5 INCHES EXTENDING FROM ALLEGHENY COUNTY TO
WESTMORELAND COUNTY IN PENNSYLVANIA. 

THE WPC QPF FROM THE 17/00Z CYCLE HAD SOME AREAL AVERAGE VALUES
APPROACHING 0.25 INCHES OVER PORTIONS OF WESTERN PA THIS
EVENING...AND A FEW OF THE HIGHER RESOLUTION MODELS HAVE LOCALIZED
AMOUNTS OF HALF AN INCH OR MORE.  A QUICK LOOK AT THE 00Z SOUNDING
DATA SHOWED THAT THERE WERE STILL SOME STEEP LOW/MID LEVEL LAPSE
RATES AND LOW LEVEL MOISTURE WERE IN PLACE...SUGGESTING THAT
LOCALIZED HEAVIER RAINFALL RATES ARE POSSIBLE THROUGH 03Z.

BANN

ATTN...WFO...BUF...CLE...CTP...PBZ...

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

LAT...LON   42117943 41247920 40087879 39487969 40248044 
            41778059