ZCZC SPCSWOMCD ALL ACUS11 KWNS 311651 SPC MCD 311651 PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-311845- MESOSCALE DISCUSSION 0851 NWS STORM PREDICTION CENTER NORMAN OK 1151 AM CDT SUN MAY 31 2015 AREAS AFFECTED...FAR ERN OH / WV PANHANDLE AND ERN WV / NWRN VA / WRN MD / WRN-CNTRL PA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 311651Z - 311845Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...A COUPLE OF STRONG STORMS WILL LIKELY DEVELOP THIS AFTERNOON. A FEW OF THESE STORMS MAY POSE A MARGINAL/LOCALIZED SEVERE THREAT. THE ANTICIPATED COVERAGE OF SEVERE ACTIVITY WILL LIKELY PRECLUDE A SEVERE THUNDERSTORM WATCH. DISCUSSION...MIDDAY SATELLITE IMAGERY SHOWS A SHORTWAVE TROUGH SHEARING NEWD ACROSS ADJACENT PORTIONS OF OH/PA/NY WHILE A BUBBLING CU FIELD BECOMES MORE WIDESPREAD. A SURFACE LOW ANALYZED OVER W-CNTRL OH WILL MIGRATE EWD ALONG A FRONT LOCATED OVER NERN OH AND THE NRN THIRD OF PA. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS HAVE RECENTLY DEVELOPED ACROSS THE UPPER OH VALLEY AND CNTRL APPALACHIANS. WEAK MID-LEVEL LAPSE RATES AND A WEAK CAP SAMPLED BY THE 12Z PIT RAOB /BELOW 6 DEG C PER KM/ COMBINED WITH TEMP/DEWPOINTS IN THE NEAR 80 DEG F/LOWER TO MID 60S RESPECTIVELY...HAS CONTRIBUTED TO WEAK BUOYANCY /500 J PER KG MLCAPE/. AS FORCING FOR ASCENT ASSOCIATED WITH THE MID-LEVEL PERTURBATION COUPLED WITH A REMOVAL OF MLCIN OCCURS...PARCELS LIFTING THROUGH THEIR LFC SHOULD PROMOTE A FURTHER INCREASE IN THUNDERSTORM COVERAGE THROUGH MID AFTERNOON. THE SLIGHT ENHANCEMENT OF TROPOSPHERIC SWLY/S MAY RESULT IN A FEW STRONGER MULTICELLS AND PERHAPS TRANSIENT SUPERCELL STRUCTURE FROM ERN OH EWD INTO CNTRL PA. FARTHER S OVER THE VA/WV/MD REGION...WEAKER OVERALL FLOW WILL TEND TO LIMIT STORM ORGANIZATION BUT SMALL HAIL/LOCALIZED STRONG WIND GUSTS ARE POSSIBLE WITH THIS ACTIVITY TOO. ..SMITH/MEAD.. 05/31/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CTP...LWX...PBZ...CLE... LAT...LON 40508101 41148056 41537866 41117655 40487648 40067660 38657848 38577932 39597896 39598078 39848094 40508101 NNNN