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WWUS20 KWNS 092045

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SPC WW 092045

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 499

NWS STORM PREDICTION CENTER NORMAN OK

440 PM EDT MON JUL 9 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHERN NEW YORK

       NORTHERN AND CENTRAL VERMONT



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 440 PM UNTIL

1100 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 45

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF

SARANAC LAKE NEW YORK TO 30 MILES EAST NORTHEAST OF MONTPELIER

VERMONT.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 494. WATCH NUMBER 494 WILL NOT

BE IN EFFECT AFTER 440 PM EDT. CONTINUE...WW 495...WW 496...WW

497...WW 498...



DISCUSSION...TSTMS HAVE REDEVELOPED ACROSS REGION WITHIN

DESTABILIZING AIR MASS WITH MLCAPES OF 500-1500 J/KG.  STRONGEST

VERTICAL SHEAR RESIDES NEAR AND E OF WARM FRONT ORIENTED IN N-S

FASHION ALONG THE HUDSON VALLEY.  AS SUCH...POTENTIAL WILL EXIST FOR

SUPERCELLS AND/OR BOWING STRUCTURES CAPABLE OF DAMAGING WINDS AND

LARGE HAIL THROUGH THE EVENING HOURS.  A BRIEF TORNADO IS POSSIBLE

WITH ANY MATURE STORMS CROSSING WARM FRONTAL BOUNDARY...THOUGH

HAIL/HIGH WINDS WILL REMAIN THE PRIMARY SEVERE THREATS.



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 450. MEAN STORM

MOTION VECTOR 28035.





...MEAD/THOMPSON

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