MESOSCALE DISCUSSION 1250
   NWS STORM PREDICTION CENTER NORMAN OK
   0501 PM CDT THU JUN 16 2011
   
   AREAS AFFECTED...UPPER OH VALLEY...CNTRL APPALACHIANS...MID-ATLANTIC
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 162201Z - 162330Z
   
   ISOLATED DAMAGING WIND AND MARGINAL SEVERE HAIL WILL REMAIN POSSIBLE
   WITH SEVERAL CLUSTERS/SHORT-LINE SEGMENTS EVOLVING EWD IN
   ASSOCIATION WITH SHORT WAVE TROUGH CENTERED OVER NRN OH. GIVEN THE
   ISOLATED/MARGINAL NATURE OF THE THREAT...A WW ISSUANCE DOES NOT
   APPEAR NECESSARY.
   
   TSTM CLUSTERS WERE QUITE NUMEROUS AS OF 22Z ACROSS THE UPPER OH
   VALLEY AND SE INTO PORTIONS OF THE LOWER MID-ATLANTIC. ACTIVITY HAS
   GENERALLY STRUGGLED TO BECOME ROBUST...LIKELY OWING TO ONLY WEAK
   BUOYANCY E OF THE NRN OH SHORT WAVE TROUGH WITH SURFACE TEMPERATURES
   HOLDING IN THE 60S/70S ACROSS PA/CENTRAL APPALACHIANS. WHERE GREATER
   SURFACE HEATING HAS OCCURRED INTO THE LOWER MID-ATLANTIC...MID-LEVEL
   LAPSE RATES ARE POOR /AS SAMPLED BY 17Z IAD RAOB/. WITH STRONGER
   DEEP-LAYER SHEAR GENERALLY CONFINED IMMEDIATELY S/SW OF THE SHORT
   WAVE TROUGH...EFFECTIVE SHEAR VALUES OF 20-30 KT SHOULD REMAIN
   COMMON INVOF ONGOING TSTMS. NEVERTHELESS...SETUP SHOULD YIELD
   SPORADIC DAMAGING WINDS WITH STRONGER CORES AND PERHAPS MARGINALLY
   SEVERE HAIL.
   
   ..GRAMS.. 06/16/2011
   
   
   ATTN...WFO...PHI...BGM...AKQ...BUF...MHX...CTP...LWX...RAH...
   PBZ...RLX...CLE...
   
   LAT...LON   39488161 39868102 41328027 42177961 42467822 42427760
               41117636 39007585 37027627 36237676 35857734 35987782
               37197773 38527759 39077875 39038128 39488161