MESOSCALE DISCUSSION 1913
   NWS STORM PREDICTION CENTER NORMAN OK
   1148 AM CDT TUE AUG 09 2011
   
   AREAS AFFECTED...SERN PA...NRN DE...SRN/CNTRL NJ
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 091648Z - 091745Z
   
   INITIAL STORMS MOVING THROUGH THE UPPER MID ATLANTIC WILL PRODUCE
   ISOLATED STRONG TO SEVERE WINDS AND PERHAPS A TORNADO. ALTHOUGH A WW
   IS NOT EXPECTED AT THIS TIME...ONE MAY BECOME NECESSARY LATER THIS
   AFTERNOON.
   
   A FEW THUNDERSTORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS
   PORTIONS OF THE UPPER MID ATLANTIC IN ADVANCE OF A NEGATIVELY TILTED
   SHORT WAVE TROUGH ACROSS SRN/ERN ONTARIO SEWD INTO CNTRL VA. A WEAK
   VORT MAX IS OBSERVED ON WV IMAGERY OVER WRN/CNTRL NY...AND INTO
   CNTRL NY...PROVIDING SUBTLE UPPER FORCING FOR CONTINUED CONVECTIVE
   DEVELOPMENT. BROAD WARM ADVECTION REGIME MAY CONTINUE TO SUPPORT THE
   DEVELOPMENT OF THUNDERSTORMS THROUGHOUT THE EARLY AFTERNOON...THOUGH
   CLOUD COVER IS LIMITING DESTABILIZATION AT THE MOMENT. 12Z IAD AND
   APG SOUNDINGS REFLECT POOR LOW/MID LEVEL LAPSE RATES...WHICH MAY
   INITIALLY ONLY SUPPORT ISOLATED STRONG TO SEVERE DEVELOPMENT UNTIL
   LATER THIS AFTERNOON. HOWEVER...RECENT DOVER VAD WIND PROFILE DATA
   SHOWS NEAR 300 M2/S2 0-3 KM SRH...WHICH WILL BE SUPPORTIVE OF
   OCCASIONALLY ROTATING STORMS CAPABLE OF DMGG WINDS AND PERHAPS AN
   ISOLATED TORNADO. DUE TO THE INITIALLY ISOLATED NATURE...A WW IS NOT
   ANTICIPATED AT THIS TIME...BUT MAY BECOME NECESSARY LATER THIS
   AFTERNOON.
   
   ..HURLBUT.. 08/09/2011
   
   
   ATTN...WFO...OKX...PHI...
   
   LAT...LON   40367400 39577431 39677549 39947589 40477559 40747512
               40637441 40367400