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WWUS20 KWNS 162041

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DEZ000-MDZ000-NJZ000-PAZ000-CWZ000-170300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 152

NWS STORM PREDICTION CENTER NORMAN OK

440 PM EDT SAT APR 16 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       DELAWARE

       EASTERN MARYLAND

       SOUTHWEST NEW JERSEY

       SOUTHERN PENNSYLVANIA

       COASTAL WATERS



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 440 PM UNTIL

1100 PM EDT.



TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND

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

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 35 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF ALTOONA

PENNSYLVANIA TO 55 MILES EAST OF HARRISBURG PENNSYLVANIA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU2).



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 150...WW 151...



DISCUSSION...STRONG PRESSURE FALLS OCCURRING OVER ERN PA/NJ ARE

INDICATIVE OF INTENSE LOW-LEVEL WAA AND THE NEWD PROGRESSION OF

SURFACE LOW CURRENTLY ANALYZED OVER WRN VA /N OF ROA/.  WHILE

AMBIENT AIR MASS IS EXPECTED TO REMAIN ONLY MARGINALLY

UNSTABLE...THE PRESENCE OF STRONG LARGE-SCALE FORCING FOR ASCENT AND

EXTREME VERTICAL SHEAR INDICATE A RISK FOR BOWING AND/OR SUPERCELL

STRUCTURES CAPABLE OF DAMAGING WIND GUSTS AND A COUPLE TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

300. MEAN STORM MOTION VECTOR 20045.





...MEAD

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