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WWUS20 KWNS 042254

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SPC WW 042254

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 99

NWS STORM PREDICTION CENTER NORMAN OK

550 PM EST TUE MAR 4 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MARYLAND

       EASTERN NORTH CAROLINA

       EASTERN AND NORTHERN VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS TUESDAY AFTERNOON AND WEDNESDAY MORNING FROM 550

PM UNTIL 300 AM EST.



TORNADOES...HAIL TO 1 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 60 STATUTE

MILES EAST AND WEST OF A LINE FROM 45 MILES SOUTH SOUTHEAST OF

NEW BERN NORTH CAROLINA TO 40 MILES NORTH NORTHWEST OF WASHINGTON

DISTRICT OF COLUM.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 96...WW 97...WW 98...



DISCUSSION...VERY INTENSE VERTICAL MOTION FIELDS AND LOW/DEEP LAYER

SHEAR WILL OVERSPREAD THIS REGION THROUGH TONIGHT AS STRONG UPPER

SYSTEM BEGINS TO LIFT NEWD ACROSS THE APPALACHIANS.  ALTHOUGH

INSTABILITY WILL REMAIN MEAGER...MOISTENING LOW LEVELS CONCURRENT

WITH 70+ KT SLY LLJ WILL ENHANCE THE POTENTIAL FOR LOW LEVEL

ROTATION AND POSSIBLE TORNADOES.  ACTIVITY MAY OCCUR IN TWO

BANDS...ONE NOW MOVING INTO CENTRAL NC/VA AND ANOTHER SPREADING

ENEWD ALONG THE MAIN COLD FRONT LATER TONIGHT.  SEVERE/TORNADO

THREAT MAY PERSIST WELL INTO THE NIGHT UNTIL THE LATER BAND MOVES

OFFSHORE.



AVIATION...TORNADOES AND 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 400.

MEAN STORM MOTION VECTOR 23040.





...EVANS

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