

019 

WWUS20 KWNS 280441

SEL7

SPC WW 280441

DCZ000-MDZ000-NCZ000-TNZ000-VAZ000-WVZ000-CWZ000-281200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 247

NWS STORM PREDICTION CENTER NORMAN OK

1240 AM EDT THU APR 28 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MARYLAND

       NORTHERN NORTH CAROLINA

       FAR NORTHEAST TENNESSEE

       VIRGINIA

       EASTERN WEST VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS THURSDAY MORNING FROM 1240 AM UNTIL 800 AM EDT.



TORNADOES...HAIL TO 1.5 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 80 STATUTE

MILES EAST AND WEST OF A LINE FROM 30 MILES NORTHEAST OF

MARTINSBURG WEST VIRGINIA TO 50 MILES WEST OF GREENSBORO NORTH

CAROLINA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 238...WW 239...WW

240...WW 241...WW 242...WW 244...WW 245...WW 246...



DISCUSSION...TSTMS CURRENTLY CRESTING THE BLUE RIDGE ARE EXPECTED TO

INTENSIFY DURING THE EARLY MORNING HOURS AS THEY ENCOUNTER A MOIST

AND MODERATELY UNSTABLE AIR MASS IN PLACE ACROSS THE PIEDMONT.

GIVEN THE STRONG VERTICAL SHEAR IN PLACE...THE SETUP WILL FAVOR A

CONTINUATION OF SUPERCELLS AND BOWING STRUCTURES CAPABLE OF

TORNADOES...DAMAGING WINDS AND HAIL.



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

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

400. MEAN STORM MOTION VECTOR 23045.





...MEAD

