MESOSCALE DISCUSSION 1786
   NWS STORM PREDICTION CENTER NORMAN OK
   0340 PM CDT FRI JUL 29 2011
   
   AREAS AFFECTED...PORTIONS NY/PA/NJ...SWRN NEW ENGLAND.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 699...
   
   VALID 292040Z - 292215Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 699
   CONTINUES.
   
   PRIMARY SVR POTENTIAL SHOULD BE OVER SRN/ERN PORTIONS WW...ALTHOUGH
   AT LEAST ISOLATED SVR CANNOT BE RULED OUT AHEAD OF SFC COLD FRONT
   NOW MOVING INTO NWRN PORTIONS WW.  WW MAY BE CLEARED FROM NW-SE
   DURING NEXT FEW HOURS AS FRONTAL/INSTABILITY TRENDS WARRANT.  SVR
   POTENTIAL SHOULD DIMINISH WITH EWD EXTENT INTO WRN PORTIONS CT/MA AS
   AIR MASS BECOMES MORE STABLE.
   
   SFC MESOANALYSIS SHOWS LOW OVER ST LAWRENCE RIVER VALLEY NE OF LK
   ONT...WITH COLD FRONT SWWD ACROSS WRN NY AND NWRN PA TO CENTRAL OH. 
   AHEAD OF FRONT...CONFLUENCE LINE AND ACCOMPANYING ZONE OF FOCUSED
   LOW-LEVEL ASCENT IS SUPPORTING BKN BAND OF STG/ISOLATED SVR TSTMS
   FROM CENTRAL PA WSWWD TO SERN OH...ALONG SRN FRINGES OF MOST
   FAVORABLE WIND PROFILES ALOFT.  WARM FRONT IS MOVING NEWD ACROSS
   NWRN/CENTRAL NJ AND EXTREME NERN PA IN ERRATIC FASHION...GIVEN
   DIFFERENTIAL HEATING/MIXING PROCESSES BEHIND EARLIER CLOUD COVER. 
   ASSOCIATED THETAE/INSTABILITY GRADIENT IS RATHER DIFFUSE...AND AS
   SUCH...MODIFIED SOUNDINGS SUGGEST EFFECTIVE LIFTED PARCELS ARE
   SFC-BASED WELL INTO FRONTAL ZONE OVER NRN NJ AND SERN NY.  SUPPORTED
   BY SFC HEATING AND DEW POINTS 70S F...MLCAPE RANGES FROM AROUND 1000
   J/KG NEAR NY/CT BORDER TO NEARLY 3000 J/KG OVER SERN PA AND SRN NJ
   NEAR DE RIVER VALLEY.  DEEP-LAYER AND LOW-LEVEL SHEAR EACH WILL
   REMAIN MOST FAVORABLE FOR SUPERCELLS AND LOCALIZED TORNADO POTENTIAL
   IN WARM-FRONTAL ZONE...WITH EFFECTIVE VALUES OF SHEAR/SRH 40-50 KT
   AND 150-250 J/KG RESPECTIVELY.  OTHERWISE...NEARLY UNIDIRECTIONAL
   WIND PROFILES ARE EVIDENT...WITH POTENTIAL FOR DEVELOPMENT OF BOWING
   SEGMENTS AND/OR LEWPS TO ENHANCE DAMAGING GUST THREAT.
   
   ..EDWARDS.. 07/29/2011
   
   
   ATTN...WFO...OKX...ALY...PHI...BGM...CTP...PBZ...
   
   LAT...LON   39517417 39807534 39917608 39727863 40258014 41977762
               42917468 42357356 41557300 39517417