

097 

WWUS20 KWNS 211842

SEL9

SPC WW 211842

OHZ000-PAZ000-WVZ000-LEZ000-220100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 509

NWS STORM PREDICTION CENTER NORMAN OK

245 PM EDT WED JUL 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST OHIO

       WESTERN PENNSYLVANIA

       NORTHERN WEST VIRGINIA PANHANDLE

       LAKE ERIE



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

900 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTHEAST

OF JAMESTOWN NEW YORK TO 45 MILES SOUTHWEST OF CLEVELAND OHIO.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 507...WW 508...



DISCUSSION...ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE

TO INTENSIFY AHEAD OF A COLD FRONT APPROACHING LK ERIE...WITH STORMS

SPREADING ACROSS THE WATCH AREA.  SUFFICIENT LOW LEVEL MOISTURE AND

CAPE...COUPLED WITH STRONG DEEP LAYER SHEAR...WILL PROMOTE

ORGANIZED/SUPERCELL STORMS CAPABLE OF DAMAGING WINDS AND HAIL.



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 29030.





...HART

