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974 

WWUS20 KWNS 301331

SEL0

SPC WW 301331

MDZ000-OHZ000-PAZ000-VAZ000-WVZ000-302100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 20

NWS STORM PREDICTION CENTER NORMAN OK

830 AM EST WED JAN 30 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN MARYLAND PANHANDLE

       SOUTHEAST OHIO

       SOUTHWEST PENNSYLVANIA

       WESTERN VIRGINIA

       WEST VIRGINIA



EFFECTIVE THIS WEDNESDAY MORNING AND AFTERNOON FROM 830 AM UNTIL

400 PM EST.



HAIL TO 1 INCH 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 EAST AND WEST OF A LINE FROM 45 MILES SOUTHWEST OF

DUBLIN VIRGINIA TO 15 MILES NORTH OF PITTSBURGH PENNSYLVANIA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 14...WW 16...WW 17...WW

18...WW 19...



DISCUSSION...NRN EXTENSION OF QLCS OVER THE UPPER OH VALLEY IS

EXPECTED TO PROGRESS EWD ACROSS THE WATCH AREA THIS MORNING INTO

EARLY AFTERNOON.  12Z OBSERVED SOUNDINGS AND ABSENCE OF LIGHTNING

INDICATE THAT AMBIENT AIR MASS IS ONLY MARGINALLY UNSTABLE...AND

CONVECTION IS QUITE SHALLOW.  NONETHELESS...INTENSE FORCING FOR

ASCENT AND VERTICAL SHEAR ARE EXPECTED TO MAINTAIN THE CONVECTIVE

SYSTEM WITH AN ATTENDANT RISK FOR PRIMARILY DAMAGING WIND GUSTS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 300. MEAN STORM MOTION

VECTOR 22045.





...MEAD

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