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Mesoscale Discussion 1687
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   MESOSCALE DISCUSSION 1687
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 AM CDT SAT SEP 06 2014

   AREAS AFFECTED...NEW ENGLAND INTO ERN PA/NRN NJ

   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

   VALID 061631Z - 061800Z

   PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   SUMMARY...BROKEN BANDS OF STRONG TO SEVERE THUNDERSTORMS WILL
   DEVELOP THIS AFTERNOON AHEAD OF A COLD FRONT AND TRACK E/NE ACROSS
   ERN PA/NRN NJ INTO NEW ENGLAND. DAMAGING WINDS WILL BE THE MAIN
   THREAT WITH THESE STORMS. A WATCH WILL LIKELY BE NEEDED WITHIN THE
   NEXT 1-2 HOURS.

   DISCUSSION...TEMPERATURES HAVE WARMED INTO THE 80S EARLY THIS
   AFTERNOON IN BROKEN CLOUDINESS AHEAD OF THE SFC COLD
   FRONT...RESULTING IN MODERATE DESTABILIZATION /MLCAPE APPROACHING
   2000 J/KG/ OF THE VERY MOIST BOUNDARY LAYER /LOW 70S DEWPOINTS/.
   AREAS OF AGITATED CUMULUS WERE EVIDENT ON LATEST VIS SATELLITE
   IMAGERY FROM CENTRAL PA NEWD INTO NEW ENGLAND IN THE VICINITY WEAK
   SFC CONFLUENCE ZONES. THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE
   NEXT HOUR OR SO IN THE VICINITY OF THIS MODEST SFC CONVERGENCE AHEAD
   OF THE MAIN COLD FRONT FROM ERN PA INTO S NY/N NJ. EFFECTIVE SHEAR
   AROUND 30-40 KT WILL BE ADEQUATE FOR SOME ORGANIZED STORM
   CLUSTERS/LINE SEGMENTS. WHILE MIDLEVEL LAPSE RATES WILL REMAIN
   POOR...STRONG SFC HEATING HAS RESULTED IN STEEP LOW LEVEL LAPSE
   RATES...AND COMBINED WITH PW VALUES AOA 1.75 INCHES...STRONG
   /LOCALLY DAMAGING/ WINDS WILL BE POSSIBLE WITH BROKEN BANDS OF
   CONVECTION. ADDITIONAL STORMS WILL DEVELOP FURTHER N/NE INTO NEW
   ENGLAND ALONG THE COLD FRONT LATER THIS AFTERNOON.

   A WATCH WILL LIKELY BE NEEDED IN THE NEXT 1-2 HOURS.

   ..LEITMAN/CORFIDI.. 09/06/2014


   ATTN...WFO...CAR...GYX...BOX...BTV...OKX...ALY...PHI...BGM...
   CTP...

   LAT...LON   40947232 40277394 40157516 40307616 40557702 40867728
               41287735 41457720 42317614 43307451 44037318 45527011
               46596801 46636776 46226731 45496713 44986720 44466785
               41617137 40947232 

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Page last modified: September 06, 2014
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