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592 

WWUS20 KWNS 091643

SEL0

SPC WW 091643

NYZ000-VTZ000-LOZ000-092300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 280

NWS STORM PREDICTION CENTER NORMAN OK

1245 PM EDT SAT MAY 9 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       MUCH OF NEW YORK

       WESTERN VERMONT

       LAKE ONTARIO



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1245 PM UNTIL

700 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 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES WEST OF

BUFFALO NEW YORK TO 25 MILES NORTH NORTHEAST OF RUTLAND VERMONT.

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...AS VERY STRONG MID/UPPER WIND MAX APPROACH NY FROM THE

W AND AIR MASS BECOMES MDTLY UNSTABLE...THUNDERSTORMS WILL INCREASE

IN NUMBER/INTENSITY FROM W TO E ACROSS THE WATCH AREA.  AS STORMS

DEVELOP INTO LINE SEGMENTS/BOWS...WIND DAMAGE WILL BECOME AN

INCREASING THREAT GIVEN FAST STORM MOVEMENT.  SUPERCELLS WILL BECOME

POSSIBLE DURING THE AFTERNOON AS LOW LEVEL SHEAR BECOMES MORE

FAVORABLE AS SURFACE LOW DEEPENS ENEWD ALONG ST LAWRENCE VALLEY.



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 450. MEAN STORM

MOTION VECTOR 26040.





...HALES

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