

046 

WWUS20 KWNS 161658

SEL1

SPC WW 161658

NYZ000-OHZ000-PAZ000-WVZ000-LOZ000-170000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 311

NWS STORM PREDICTION CENTER NORMAN OK

100 PM EDT SAT MAY 16 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL NEW YORK

       FAR SOUTHEAST OHIO

       WESTERN AND CENTRAL PENNSYLVANIA

       FAR NORTHWEST WEST VIRGINIA

       LAKE ONTARIO



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 100 PM UNTIL

800 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 90

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH

NORTHEAST OF SYRACUSE NEW YORK TO 45 MILES SOUTH SOUTHEAST OF

LATROBE PENNSYLVANIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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...THUNDERSTORMS EXPECTED TO INCREASE IN BOTH COVERAGE AND

INTENSITY ACROSS WW THROUGH LATE TODAY AHEAD OF SURFACE COLD FRONT

AND STRONG MID/UPPER TROUGH LIFTING ACROSS THE GREAT LAKES.  AIR

MASS WILL DESTABILIZE SUFFICIENTLY FOR STRONG STORMS...WITH

SUFFICIENT SHEAR FOR ORGANIZED LINES AND PERHAPS A FEW SUPERCELLS.

APPEARS PRIMARY THREAT WILL BE FROM DAMAGING WINDS AND SEVERE

HAIL...ALTHOUGH STRONG LOW LEVEL SHEAR INTO NRN PA/NY MAY SUPPORT

ROTATION AND AN ISOLATED TORNADO ACROSS THAT AREA.



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 400. MEAN STORM

MOTION VECTOR 26030.





...EVANS

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