

039 

WWUS20 KWNS 161729

SEL1

SPC WW 161729

DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-170100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 151

NWS STORM PREDICTION CENTER NORMAN OK

130 PM EDT SAT APR 16 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       DISTRICT OF COLUMBIA

       MARYLAND

       NORTHERN VIRGINIA

       EASTERN WEST VIRGINIA

       COASTAL WATERS



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 130 PM UNTIL

900 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 80 STATUTE

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

MARTINSBURG WEST VIRGINIA TO 25 MILES WEST OF RICHMOND VIRGINIA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



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...



DISCUSSION...A STRONGLY FORCED BAND OF TSTMS DEVELOPING ALONG

SYNOPTIC COLD FRONT IS EXPECTED TO PROGRESS EWD ACROSS THE WW AREA

THIS AFTERNOON INTO EVENING.  INTENSE PRESSURE FALLS OVER THE MID

ATLANTIC STATES ARE RESULTING IN THE NWD FLUX OF AN INCREASINGLY

WARM AND MOIST BOUNDARY LAYER INTO THE AREA WHICH WILL ALLOW FOR

STORMS TO BECOME PROGRESSIVELY SURFACE-BASED.  GIVEN THE VERY STRONG

WIND FIELD IN PLACE...THE POTENTIAL WILL EXIST FOR EMBEDDED BOWING

AND SUPERCELL STRUCTURES WITH A RISK FOR TORNADOES AND DAMAGING WIND

GUSTS.



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

350. MEAN STORM MOTION VECTOR 21050.





...MEAD

