MESOSCALE DISCUSSION 1553
   NWS STORM PREDICTION CENTER NORMAN OK
   0334 AM CDT WED AUG 13 2014

   AREAS AFFECTED...SE NY...LONG ISLAND...SRN NEW ENGLAND

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 130834Z - 131000Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...A MARGINAL THREAT FOR TORNADOES AND DAMAGING WIND GUSTS
   MAY DEVELOP OVER THE NEXT FEW HOURS AS CELLS MOVE ONSHORE IN THE NEW
   YORK CITY AREA. THE THREAT IS EXPECTED TO REMAIN ISOLATED AND
   CONDITIONAL WHICH MEANS WW ISSUANCE WILL LIKELY BE UNNECESSARY.

   DISCUSSION...LATEST SFC ANALYSIS SHOWS A 1006 MB MESOSCALE SFC LOW
   OFFSHORE OVER ECNTRL NJ WITH BACKED EAST TO SOUTHEASTERLY FLOW OVER
   MUCH OF NJ...NY AND NEW ENGLAND WHERE A VERY MOIST AIRMASS IS IN
   PLACE. SFC DEWPOINTS RANGE FROM 65 TO 70 F ACROSS THE MD AREA WITH A
   POCKET OF INSTABILITY WITH SBCAPE OF 250 TO 500 J/KG ANALYZED JUST
   OFFSHORE. IN ADDITION...THE WSR-88D VWP AT UPTON NY SHOWS A STRONGLY
   VEERING WIND PROFILE WITH HEIGHT RESULTING IN 0-3 KM STORM RELATIVE
   HELICITY ABOVE 500 M2/S2. THIS COMBINED WITH 0-6 KM SHEAR OF 65 TO
   70 KT SHOULD BE ENOUGH FOR STORM ROTATION WITH THE CELLS THAT ARE
   JUST SOUTH OF NEW YORK CITY. SHOULD SUFFICIENT INSTABILITY DEVELOP
   INLAND AS THIS ACTIVITY MOVES NWD OVER THE NEXT HOUR OR TWO...A
   BRIEF TORNADO AND MARGINALLY SEVERE WIND GUSTS WILL BE POSSIBLE.

   ..BROYLES/MEAD.. 08/13/2014


   ATTN...WFO...BOX...OKX...ALY...PHI...

   LAT...LON   41847155 42167289 41767403 40707450 40267405 40267316
               40927167 41847155