SEL9
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 259
   NWS STORM PREDICTION CENTER NORMAN OK
   155 PM CDT THU MAY 12 2005
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          SOUTHWESTERN IOWA
          NORTHEASTERN KANSAS
          NORTHWESTERN MISSOURI
          SOUTHEASTERN NEBRASKA
   
   EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 155 PM UNTIL
   900 PM CDT.
   
   TORNADOES...HAIL TO 3 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 65 STATUTE MILES
   EAST AND WEST OF A LINE FROM 25 MILES WEST NORTHWEST OF OMAHA
   NEBRASKA TO 35 MILES SOUTH SOUTHEAST OF TOPEKA KANSAS. FOR A
   COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
   UPDATE (WOUS64 KWNS WOU9).
   
   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 257...WW 258...
   
   DISCUSSION...CONVECTION BEGINNING TO DEVELOP ALONG OUTFLOW BOUNDARY
   FROM YESTERDAYS CONVECTION...WEST OF LNK/BIE TO NORTHEAST OF MHK
   EARLY THIS AFTERNOON.  AIR MASS EAST OF THIS LINE OVER NERN KS AND
   NWRN MO HAS ALREADY BECOME MODERATELY UNSTABLE AND WEAKLY
   CAPPED...WITH HEATING EXPECTED TO DESTABILIZE ATMOSPHERE FURTHER
   INTO SERN NEB AND FAR SWRN IA. BACKED LOW LEVEL WINDS ACROSS WATCH
   AREA WILL ENHANCE THE POTENTIAL FOR SUPERCELLS AND TORNADOES.  VERY
   LARGE HAIL IS ALSO A CONCERN WITH SUPERCELLS AS THEY MOVE ENEWD
   THROUGH THE EVENING.
   
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND
   GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
   MEAN STORM MOTION VECTOR 24020.
   
   
   ...EVANS