April 27: PDS Tornado Watch #3

URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 238
   NWS STORM PREDICTION CENTER NORMAN OK
   335 PM CDT WED APR 27 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          MIDDLE AND EASTERN TENNESSEE
   
   EFFECTIVE THIS WEDNESDAY AFTERNOON FROM 335 PM UNTIL MIDNIGHT CDT.
   
   ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
   
   DESTRUCTIVE TORNADOES...LARGE HAIL TO 3 INCHES IN DIAMETER...
   THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
   POSSIBLE IN THESE AREAS.
   
   THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
   MILES NORTH AND SOUTH OF A LINE FROM 70 MILES WEST SOUTHWEST OF
   NASHVILLE TENNESSEE TO 25 MILES EAST OF KNOXVILLE TENNESSEE.  FOR
   A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
   OUTLINE UPDATE (WOUS64 KWNS WOU8).
   
   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 233...WW
   234...WW 235...WW 236...
   
   DISCUSSION...A VERY UNSTABLE AIRMASS IS EXPECTED TO GRADUALLY
   DEVELOP NORTHWARD INTO TN THIS EVENING IN THE WAKE OF A MORNING MCS.
   WITHIN AN INCREASINGLY SHEARED ENVIRONMENT...ACCENTUATED BY
   LONG/CURVING LOW LEVEL HODOGRAPHS...SUPERCELLS CAPABLE OF TORNADOES
   /SOME STRONG/ WILL BE AN INCREASING/MORE WIDESPREAD CONCERN INTO
   THIS EVENING.
   
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
   WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
   550. MEAN STORM MOTION VECTOR 24040.