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


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

   LAT...LON   40508101 41148056 41537866 41117655 40487648 40067660
               38657848 38577932 39597896 39598078 39848094 40508101