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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 383

NWS STORM PREDICTION CENTER NORMAN OK

250 PM EDT THU MAY 26 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN PENNSYLVANIA



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 250 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 60 STATUTE

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

WILLIAMSPORT PENNSYLVANIA TO 15 MILES WEST SOUTHWEST OF

HAGERSTOWN MARYLAND.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 379...WW 380...WW

381...WW 382...



DISCUSSION...TSTMS ARE EXPECTED TO DEVELOP WITHIN THE NEXT HOUR

ALONG NNE-SSW ORIENTED CONFLUENCE BAND THAT HAS BECOME ESTABLISHED

OVER CNTRL PA THIS AFTERNOON.  E OF THIS BOUNDARY...AIR MASS IS WARM

AND MOIST WITH MLCAPE VALUES OF 2000-3000 J/KG.  CURRENT STATE

COLLEGE PA VAD SHOWS A VERTICALLY VEERING WIND PROFILE THROUGH THE

LOWEST 1-2 KM AGL WITH 40-50 KT SWLY FLOW ABOVE 3 KM AGL.  AS

SUCH...SETUP WILL FAVOR THE DEVELOPMENT OF SUPERCELLS CAPABLE OF

VERY LARGE HAIL AND DAMAGING WINDS.  T-TD SPREADS DECREASE WITH EWD

EXTENT FROM CONFLUENCE ZONE...AND SURFACE WINDS BACK TO SLY/SSELY.

THUS...ANY SUPERCELLS THAT CAN EVOLVE WILL HAVE AN INCREASED THREAT

FOR TORNADOES WHILE MOVING NEWD INTO THE MORE MOIST AND MORE

STRONGLY SHEARED ENVIRONMENT IN PLACE ACROSS THE ERN HALF OF THE

STATE.



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

500. MEAN STORM MOTION VECTOR 24030.





...MEAD

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