

000 

WWUS20 KWNS 031656

SEL0

SPC WW 031656

MEZ000-NHZ000-NYZ000-PAZ000-VTZ000-LOZ000-CWZ000-040200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 560

NWS STORM PREDICTION CENTER NORMAN OK

1255 PM EDT FRI AUG 3 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       MAINE

       NEW HAMPSHIRE

       MUCH OF NEW YORK

       NORTH CENTRAL PENNSYLVANIA

       VERMONT

       LAKE ONTARIO

       COASTAL WATERS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL

1000 PM EDT.



HAIL TO 2 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 90

STATUTE MILES EITHER SIDE OF A LINE FROM 35 MILES SOUTH SOUTHWEST

OF ROCHESTER NEW YORK TO 50 MILES NORTHEAST OF BAR HARBOR MAINE.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).



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.



DISCUSSION...LINE OF CONVECTION CONTINUES TO DEVELOP RAPIDLY AHEAD

OF ADVANCING COLD FRONT MOVING EWD AND SEWD OUT OF ONTARIO AND

QUEBEC.  AIR MASS ACROSS THIS REGION IS MODERATELY UNSTABLE WITH

MLCAPE VALUES TO 2000 J/KG.  ACTIVITY WILL CONTINUE TO

DEVELOP/INTENSIFY OVER THE NEXT SEVERAL HOURS WITH THE MAIN THREAT

BEING DAMAGING WINDS AND HAIL.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM

MOTION VECTOR 24035.





...MCCARTHY

