Wednesday, April 27, 2011

April 27: PDS Tornado Watch #4


URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 241
   NWS STORM PREDICTION CENTER NORMAN OK
   650 PM EDT WED APR 27 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          EASTERN ALABAMA
          NORTHERN AND CENTRAL GEORGIA
          WESTERN NORTH CAROLINA
          UPSTATE SOUTH CAROLINA
   
   EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 650 PM
   UNTIL 200 AM 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 90 STATUTE
   MILES EAST AND WEST OF A LINE FROM 35 MILES NORTHWEST OF HICKORY
   NORTH CAROLINA TO 35 MILES EAST SOUTHEAST OF MONTGOMERY ALABAMA. 
   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 232...WW 234...WW
   235...WW 236...WW 237...WW 238...WW 239...WW 240...
   
   DISCUSSION...LONG-LIVED SUPERCELLS WITH A HISTORY OF DESTRUCTIVE
   TORNADOES OVER PORTIONS OF ERN TN AND AL ARE EXPECTED TO RAPIDLY
   MOVE EWD INTO THE WW AREA THIS EVENING.  EWD MIGRATION OF 50-60+ KT
   LLJ AXIS WILL SUPPORT CONTINUED AIR MASS DESTABILIZATION WITH MLCAPE
   VALUES REMAINING IN THE 1000-2000 J/KG RANGE.  WHEN COUPLED WITH
   50-70 KT EFFECTIVE BULK SHEAR AND STEADILY STRENGTHENING LOW-LEVEL
   SHEAR...SETUP WILL REMAIN QUITE SUPPORTIVE OF SIGNIFICANT
   TORNADOES...SOME OF WHICH COULD BE LONG-TRACKED.
   
   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
   500. MEAN STORM MOTION VECTOR 24045.

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