MESOSCALE DISCUSSION 1928
   NWS STORM PREDICTION CENTER NORMAN OK
   1038 AM CDT SAT SEP 08 2012
   
   AREAS AFFECTED...PARTS OF THE NRN/CNTRL APPALACHIANS
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 634...
   
   VALID 081538Z - 081715Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 634
   CONTINUES.
   
   SUMMARY...DAMAGING WIND THREAT SHOULD PERSIST WITHIN WW 634 ALONG A
   THIN FRONTAL SQUALL LINE CURRENTLY IN SWRN NY. ALONG WITH THE SRN
   EXTENT OF THE LINE IN WRN PA AND WV...THIS QLCS SHOULD INTENSIFY
   RAPIDLY AS IT REACHES THE INSTABILITY AXIS FROM NRN VA TO CNTRL NY
   IN THE EARLY AFTERNOON...WITH A SUBSTANTIAL INCREASE IN THE DAMAGING
   WIND THREAT EXPECTED. A DOWNSTREAM TORNADO WATCH IS ANTICIPATED FOR
   WFO BTV/ALY/BGM AND A SEVERE THUNDERSTORM WATCH IS EXPECTED FOR
   CTP/LWX/PHI.
   
   DISCUSSION...A NARROW BUT LONG BAND OF ENHANCED REFLECTIVITY WITHOUT
   CG DETECTED LIGHTNING EXTENDED FROM SWRN NY TO ERN KY AS OF
   1530Z...ALONG THE SURFACE COLD FRONT. AN 80-100 MILE GAP REMAINS
   BETWEEN THIS AND THE LEADING EDGE OF MORE ROBUST SURFACE HEATING
   WHERE 15Z TEMPERATURES HAD RISEN THROUGH THE 70S AND LOWER 80S. AS
   THE FRONT MERGES WITH THIS INSTABILITY AXIS...A SUBSTANTIAL INCREASE
   IN CONVECTIVE INTENSITY IS ANTICIPATED. LOW/DEEP-LAYER SHEAR WILL BE
   STRONGEST WITH NRN EXTENT...WHILE STRONGER HEATING WITH SRN EXTENT
   SHOULD PROMOTE RELATIVELY GREATER BUOYANCY. THIS SETUP APPEARS TO BE
   SUPPORTIVE FOR THE ADVERTISED POTENTIAL OF SCATTERED TO NUMEROUS
   DAMAGING WIND EVENTS. A FEW EMBEDDED QLCS TORNADOES ALSO APPEAR
   PROBABLE ACROSS CNTRL/ERN NY.
   
   ..GRAMS.. 09/08/2012
   
   
   ATTN...WFO...BTV...ALY...PHI...BGM...BUF...CTP...LWX...
   
   LAT...LON   44207583 44357519 44107392 43587349 42307406 39397642
               38317767 38227840 38497933 39837876 42027707 44207583