URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 508
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM EDT THU JUN 25 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
WESTERN INTO PART OF UPSTATE NEW YORK
LAKE ERIE
LAKE ONTARIO
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 1240 PM UNTIL
800 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 90
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST
SOUTHEAST OF JAMESTOWN NEW YORK TO 55 MILES NORTH NORTHEAST OF
WATERTOWN NEW YORK. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).
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...CLUSTER OF INTENSE THUNDERSTORMS OVER ONTARIO WILL
CONTINUE ESEWD INTO WRN NY THIS AFTERNOON WHERE AIR MASS IS ALREADY
MODERATELY UNSTABLE. ADDITIONAL DEVELOPMENT COULD OCCUR INTO THE
ST. LAWRENCE VALLEY WITH SUBTLE SURFACE TROUGH INTERACTING WITH
INSTABILITY AXIS. SHEAR WILL BE SUFFICIENT FOR ORGANIZATION INTO
LINES/CLUSTERS AS STORMS SHIFT EAST THROUGH THE DAY. LARGE HAIL AND
DAMAGING WINDS ARE EXPECTED WITH THE STRONGER STORMS.
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 500. MEAN STORM
MOTION VECTOR 28025.
...EVANS
