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924 

WWUS20 KWNS 271909

SEL6

SPC WW 271909

MDZ000-NYZ000-PAZ000-WVZ000-LEZ000-LOZ000-280200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 236

NWS STORM PREDICTION CENTER NORMAN OK

310 PM EDT WED APR 27 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME WESTERN MARYLAND

       WESTERN NEW YORK

       WESTERN AND CENTRAL PENNSYLVANIA

       EXTREME NORTHERN WEST VIRGINIA

       LAKE ERIE

       LAKE ONTARIO



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 310 PM UNTIL

1000 PM EDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE

MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH OF ROCHESTER

NEW YORK TO 50 MILES SOUTH SOUTHWEST OF ALTOONA PENNSYLVANIA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 231...WW 232...WW

233...WW 234...WW 235...



DISCUSSION...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP SOON

OVER WESTERN PA AND SPREAD EAST-NORTHEASTWARD ACROSS THE WATCH AREA

DURING THE LATE AFTERNOON AND EVENING.  MODERATE

INSTABILITY...COUPLED WITH STRONG VERTICAL SHEAR PROFILES WILL

PROMOTE ORGANIZED STORMS WITH SUPERCELLS/BOWS POSSIBLE.  LARGE HAIL

AND DAMAGING WINDS ARE THE MAIN THREAT.  HOWEVER...SUFFICIENT LOW

LEVEL SHEAR IS PRESENT FOR ISOLATED TORNADOES.



AVIATION...TORNADOES AND 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

450. MEAN STORM MOTION VECTOR 25040.





...HART

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