

045 

WWUS20 KWNS 100048

SEL0

SPC WW 100048

NYZ000-LEZ000-LOZ000-100700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 690

NWS STORM PREDICTION CENTER NORMAN OK

850 PM EDT SUN AUG 9 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN NEW YORK

       LAKE ERIE

       LAKE ONTARIO



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 850 PM UNTIL

300 AM 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 65

STATUTE MILES EITHER SIDE OF A LINE FROM 20 MILES NORTHWEST OF

BUFFALO NEW YORK TO 20 MILES NORTHEAST OF ITHACA NEW YORK.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 684...WW 686...WW

687...WW 688...WW 689...



DISCUSSION...MCS WILL CONTINUE SHIFTING RAPIDLY SSEWD ACROSS THE

LOWER LAKES AND INTO WRN NEW YORK THIS EVENING/EARLY TONIGHT...WITH

POTENTIAL FOR DAMAGING WINDS.  DEEP LAYER SHEAR IS QUITE

STRONG...AND FEED OF SUFFICIENT INSTABILITY SHOULD SUSTAIN THIS

ACTIVITY FOR SEVERAL HOURS.



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 30040.





...EVANS

