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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 699

NWS STORM PREDICTION CENTER NORMAN OK

325 PM EDT TUE AUG 11 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL NORTH CAROLINA

       SOUTHERN VIRGINIA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 325 PM UNTIL

1000 PM EDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH

NORTHWEST OF SOUTH HILL VIRGINIA TO 10 MILES WEST OF CHARLOTTE

NORTH CAROLINA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



DISCUSSION...THUNDERSTORMS ARE INCREASING ALONG THE LEADING EDGE OF

THE MCS CROSSING THE CENTRAL APPALACHIANS.  THE ACTIVITY IS IN

ADVANCE OF A UPPER TROUGH THAT IS DIGGING SEWD ACROSS THE MIDDLE MS

AND UPPER OH VALLEY.  WESTERLY WINDS ALOFT ARE STRENGTHENING

SOMEWHAT ACROSS THE APPALACHIANS INTO THE CAROLINAS AS INDICATED BY

RECENT MRX VWP DATA SHOWING 30 KT ABOVE 3 KM AGL.  THE STORMS WILL

BE MOVING INTO AN INCREASINGLY HOT LOW LEVEL AIR MASS WHERE

TEMPERATURES ARE IN THE 90S...AND DESPITE DEW POINTS DROPPING IN THE

MID 60S...STEEP LOW LEVEL LAPSE RATES/LARGE TEMPERATURE-DEWPOINT

SPREADS MAY ENHANCE POTENTIAL FOR DAMAGING WIND GUSTS.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 27030.





...WEISS

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