MESOSCALE PRECIPITATION DISCUSSION 0283
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
441 PM EDT SUN JUN 10 2018

AREAS AFFECTED...EASTERN OH...SOUTHWEST PA...NORTHERN WV...FAR
WESTERN MD

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

VALID 102040Z - 110240Z

SUMMARY...SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL RATES WILL
BECOME A BIT MORE WIDESPREAD THROUGH THE LATE AFTERNOON AND EARLY
EVENING HOURS. SOME FLASH FLOODING IS POSSIBLE.

DISCUSSION...THE AFTERNOON GOES-16 VISIBLE SATELLITE IMAGERY SHOWS
AN MCV CROSSING PORTIONS OF NORTH-CENTRAL OH...AND THIS ENERGY IS
EXPECTED TO INTERACT WITH A MODERATELY UNSTABLE BOUNDARY LAYER
THAT IS POOLED UP ALONG A QUASI-STATIONARY FRONTAL ZONE ACROSS THE
UPPER OH VALLEY. A WAVE OF LOW PRESSURE IS ALSO NOTED ALONG THE
FRONT. MLCAPE VALUES ACROSS AREAS OF EAST-CENTRAL OH ARE NEAR 1000
J/KG AND CONVECTION THAT IS CURRENTLY NOTED OVER EASTERN OH SHOULD
EXPAND FURTHER OVER THE NEXT FEW HOURS TO INCLUDE PARTS OF WESTERN
PA/NORTHERN WV AND EVENTUALLY FAR WESTERN MD. GENERALLY THE MAIN
CONVECTIVE THREAT WILL TEND TO REMAIN CLOSE TO THE AFOREMENTIONED
FRONT.

PWATS ACROSS THE UPPER OH VALLEY ARE ON THE ORDER OF 1.6 TO 1.8
INCHES...AND WITH THE UPTICK IN BOUNDARY LAYER INSTABILITY AND
EXPANSION OF SOME COLD-TOPPED CONVECTION...THE RAINFALL RATES
SHOULD BE RATHER HEAVY AND MAY APPROACH 2 INCHES/HR. THE LATEST
HRRR/HRRRX GUIDANCE FAVORS AS MUCH AS 2 TO 3 INCHES OF RAIN
LOCALLY THROUGH MID-EVENING.

GIVEN THE WET ANTECEDENT CONDITIONS THESE RAINFALL TOTALS MAY
RESULT IN SOME FLASH FLOODING.

ORRISON

ATTN...WFO...CLE...CTP...LWX...PBZ...RLX...

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

LAT...LON   41148143 41118057 40807986 39967904 39387912
            39137997 39308058 39598110 40228171 40978196