

776 

WWUS20 KWNS 251952

SEL4

SPC WW 251952

NYZ000-PAZ000-LEZ000-LOZ000-260100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 624

NWS STORM PREDICTION CENTER NORMAN OK

350 PM EDT SAT JUL 25 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN NEW YORK

       CENTRAL PENNSYLVANIA

       LAKE ERIE

       LAKE ONTARIO



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 350 PM UNTIL

900 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 55

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTH

NORTHWEST OF ROCHESTER NEW YORK TO 50 MILES SOUTHWEST OF

HARRISBURG PENNSYLVANIA.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 623...



DISCUSSION...STRONG FORCING ASSOCIATED WITH GREAT LAKES UPPER LOW

WILL PROGRESS EWD THROUGH WRN NY/CENTRAL PA THROUGH THE AFTERNOON

AND AID IN THUNDERSTORM DEVELOPMENT/INTENSIFICATION. THE LOW AND

DEEP LAYER SHEAR IS FAVORABLE FOR SOME MID LEVEL ROTATION...WITH

LARGE HAIL AND DAMAGING WINDS THE MAIN THREAT.



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 24025.





...IMY

