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242 

WWUS20 KWNS 221832

SEL1

SPC WW 221832

MDZ000-OHZ000-PAZ000-WVZ000-230200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 681

NWS STORM PREDICTION CENTER NORMAN OK

235 PM EDT WED SEP 22 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN MARYLAND PANHANDLE

       SOUTHEAST OHIO

       WESTERN AND CENTRAL PENNSYLVANIA

       NORTHERN WEST VIRGINIA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 235 PM UNTIL

1000 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 NORTH AND SOUTH OF A LINE FROM 40 MILES WEST OF

WHEELING WEST VIRGINIA TO 35 MILES SOUTHEAST OF WILLIAMSPORT

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.



OTHER WATCH INFORMATION...CONTINUE...WW 680...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON WITHIN A STEEP LOW-LEVEL LAPSE

RATE...MODERATELY UNSTABLE ENVIRONMENT WITH MLCAPE OF 1000-1500

J/KG.  REGIONAL VWPS INDICATE MODESTLY STRONG WLY TROPOSPHERIC FLOW

WHICH WILL BE SUPPORTIVE OF SPLITTING SUPERCELL STRUCTURES AND

BOWING LINE SEGMENTS WITH THE PRIMARY HAZARD BEING DAMAGING WIND

GUSTS.



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 500. MEAN STORM

MOTION VECTOR 27035.





...MEAD

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