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WWUS20 KWNS 161609

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 150

NWS STORM PREDICTION CENTER NORMAN OK

1205 PM EDT SAT APR 16 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN NORTH CAROLINA

       CENTRAL AND EASTERN SOUTH CAROLINA

       SOUTHERN VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1205 PM UNTIL

900 PM EDT.



...THIS IS A PARTICULARLY DANGEROUS SITUATION...



DESTRUCTIVE TORNADOES...LARGE 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 95 STATUTE

MILES EAST AND WEST OF A LINE FROM 30 MILES SOUTH SOUTHEAST OF

CHARLESTON SOUTH CAROLINA TO 60 MILES NORTH NORTHEAST OF SOUTH

HILL VIRGINIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 149...



DISCUSSION...TSTMS WILL CONTINUE TO INTENSIFY TODAY ALONG AND AHEAD

OF COLD FRONT...AND THE S OF WARM FRONT RETREATING NWD THROUGH NC

INTO VA.  AMBIENT WARM SECTOR IS MOIST AND BREAKS IN THE CLOUDS WILL

SUPPORT LOCALLY STRONG DIABATIC HEATING WITH MLCAPE VALUES

INCREASING TO 1000-1500 J/KG.  THIS INSTABILITY COUPLED WITH

EFFECTIVE BULK SHEAR OF 50-60 KT...EFFECTIVE SRH VALUES OF 300-450+

M2/S2 AND ANTICIPATED DISCRETE STORM MODES SUGGESTS A HIGH

LIKELIHOOD OF LONG-LIVED SUPERCELLS CAPABLE OF SIGNIFICANT

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 24040.





...MEAD

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