URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 505
   NWS STORM PREDICTION CENTER NORMAN OK
   100 PM EDT TUE JUL 10 2007
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          WESTERN AND CENTRAL MASSACHUSETTS
          WESTERN AND CENTRAL NEW HAMPSHIRE
          EASTERN NEW YORK
          VERMONT
   
   EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 100 PM UNTIL
   900 PM EDT.
   
   HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80
   STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF
   BURLINGTON VERMONT TO 35 MILES SOUTH SOUTHWEST OF PITTSFIELD
   MASSACHUSETTS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
   ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).
   
   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.
   
   OTHER WATCH INFORMATION...CONTINUE...WW 504...
   
   DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
   INTENSITY THIS AFTERNOON WITHIN MOIST AND MODERATELY UNSTABLE
   LOW-LEVEL AIR MASS WITH MLCAPES OF 2000-3000 J/KG.  THIS INSTABILITY
   COUPLED WITH MODEST DEEP LAYER SHEAR /30-40KT OF EFFECTIVE BULK
   SHEAR/ INDICATE THE POTENTIAL FOR ORGANIZED...SEVERE STORMS
   INCLUDING A FEW SUPERCELLS CAPABLE OF DAMAGING WINDS AND LARGE HAIL.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
   MOTION VECTOR 27030.

The latest (1630z) SPC Day 1 Convective Outlook:

Wind: 30%, Hail: 30%, Torn: 2%

   ...NY INTO NEW ENGLAND TODAY...
   A VERY MOIST/UNSTABLE AIR MASS IS PRESENT ALONG AND SW OF A
   BAROCLINIC ZONE THAT EXTENDS FROM ERN MA INTO UPSTATE NY.  LIKE
   YESTERDAY...THERE IS LITTLE LARGE SCALE FOCUS FOR THUNDERSTORM
   DEVELOPMENT IN MUCH OF THE WARM SECTOR...ASIDE FROM SUBTLE SPEED
   MAXIMA BRUSHING UPSTATE NY WITHIN THE SRN FRINGE OF THE STRONGER
   MID-UPPER LEVEL WESTERLIES.  STILL...THE 12Z ALB SOUNDING SUGGESTS
   THAT MLCAPE VALUES SHOULD EXCEED 2500 J/KG WITH LITTLE CONVECTIVE
   INHIBITION AS SURFACE TEMPERATURES WARM TO 88-91 F.  WIDELY
   SCATTERED THUNDERSTORMS SHOULD DEVELOP IN ASSOCIATION WITH THE FRONT
   AND LAKE BREEZES...AS WELL AS TERRAIN INFLUENCES.  THE PRIMARY
   SEVERE THREATS SHOULD BE DAMAGING WINDS AND LARGE HAIL...GIVEN THE
   STRONG INSTABILITY AND MODEST VERTICAL SHEAR WITH 30-40 KT MID LEVEL
   FLOW. 

SL Keene Prediction:

Wind: 35%, Hail: 25%, Torn: 2%
Timing: Small cell building in southern VT may affect Keene before 4pm. Otherwise, storms are moving slowly and any development that occurs in NY will make it to Keene after 4pm.