MESOSCALE PRECIPITATION DISCUSSION 0137
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
545 PM EDT WED JUN 18 2014
 
AREAS AFFECTED...PORTIONS OF NORTHEAST OH AND WESTERN PA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 182144Z - 190344Z
 
SUMMARY...A STEADY STATE THUNDERSTORM COMPLEX IS EXPECTED TO MOVE
ACROSS AN AREA OF SATURATED SOILS ACROSS NORTHEAST OH AND WESTERN
PA.  ITS FORWARD PROGRESSION SHOULD LIMIT FLASH FLOODING TO A FEW
LOCATIONS.

DISCUSSION...A LONG-LIVED ARC OF THUNDERSTORMS IS MOVING OUT OF
SOUTHEAST MI AND ACROSS NORTHWEST OH AT THE PRESENT TIME,
AVERAGING A FORWARD MOTION OF 35 KTS -- 5-10 KTS ABOVE THE FORWARD
PROPAGATING CORFIDI VECTORS FROM THE 12Z GFS.  ITS OUTFLOW
BOUNDARY HAS A DECENT SURFACE TEMPERATURE GRADIENT, WITH NEAR 90F
READINGS AHEAD OF IT AND LOW 70S F READINGS IN ITS WAKE. 
PRECIPITABLE WATER VALUES ARE AROUND 1.75" IN ITS VICINITY, NEAR
THE 90TH PERCENTILE FOR MID JUNE.  RAINFALL RATES ARE LOCALLY
REACHING 1-1.5" AN HOUR WITHIN THIS COMPLEX, WHICH WOULD EXCEED
THE VERY LOW FLASH FLOOD GUIDANCE VALUES ACROSS NORTHEAST OH AND
WESTERN PA CAUSED BY HEAVY RAINFALL THIS MORNING.  

CAPE VALUES ARE EXPECTED TO REMAIN AT OR ABOVE 1000 J/KG OVER THE
NEXT SEVERAL HOURS, AND THE COMPLEX'S FORWARD MOTION SHOULD
PROVIDE ALL THE STORM RELATIVE INFLOW THAT THE COMPLEX NEEDS TO
SURVIVE AS A WET MULTI-CELLULAR CLUSTER.  RAINFALL RATES UP TO 2"
AN HOUR IN STRONGER STORMS ARE POSSIBLE CONSIDERING THE AVAILABLE
MOISTURE.  THE AVAILABLE MESOSCALE GUIDANCE IS MUCH TOO SLOW IN
ITS FORWARD MOTION, SO USED EXTRAPOLATION TO DETERMINE IS EXPECTED
LOCATION OVER THE NEXT SEVERAL HOURS.  A FEW POCKETS OF FLASH
FLOODING ARE POSSIBLE DUE TO SATURATED SOILS IN THIS REGION.

ROTH

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

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

LAT...LON   40818162 40478091 40578058 40268037 39648046 39688081
            39388109 39378085 39258085 39028081 39258035 39288022
            39398015 39487977 39717982 39777966 39767943 40227900
            40957866 41397852 41587874 41627903 41857929 41877965
            42167966 42287996 41988090 41758142 41348191 40818162