MESOSCALE DISCUSSION 2100
   NWS STORM PREDICTION CENTER NORMAN OK
   0757 PM CDT WED OCT 17 2007
   
   AREAS AFFECTED...SERN KS/MUCH OF MO/SERN IA/WEST CENTRAL IL
   
   CONCERNING...TORNADO WATCH 714...
   
   VALID 180057Z - 180200Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 714 CONTINUES.
   
   LARGE SCALE FORCING WITH THE NEGATIVELY TILTED CENTRAL/SRN PLAINS
   UPPER TROUGH AND WITHIN EXIT REGION OF 80+ KT JET ROUNDING BASE OF
   THIS TROUGH WILL CONTINUE TO SUPPORT TSTM DEVELOPMENT THIS EVENING
   ACROSS SERN KS INTO MUCH OF MO.  DESPITE MARGINAL INSTABILITY...
   STRONG EFFECTIVE BULK SHEAR EXCEEDING 50 KT AND EFFECTIVE SRH VALUES
   OF 300-400 M2/S2 WITHIN WW 714 CONTINUE TO RESULT IN AN ENVIRONMENT
   FAVORABLE FOR TORNADOES.  IN ADDITION TO THE TSTM ACTIVITY THAT
   EXTENDED FROM NERN TO WEST CENTRAL MO...THE SEVERE WEATHER THREAT
   WILL CONTINUE AS ACTIVITY FROM SERN KS/NERN OK TRACKS NEWD INTO THE
   SWRN PART OF WW 714 DURING THE NEXT 1-2 HOURS.
   
   TSTMS WILL CONTINUE TO SPREAD NEWD INTO ERN IA AND EVENTUALLY INTO
   WEST CENTRAL/NWRN IL.  A MORE STABLE SURFACE AIR MASS IS EXPECTED TO
   PRECLUDE A GREATER SEVERE WEATHER THREAT TO THE N AND NE OF WW 714
   INTO ERN IA AND NWRN IL.  HOWEVER...MARGINAL ELEVATED INSTABILITY
   AND INCREASING EFFECTIVE BULK SHEAR MAY SUPPORT A FEW SEVERE STORMS
   INTO THE LATE EVENING.
   
   ..PETERS.. 10/18/2007
   
   
   ATTN...WFO...PAH...ILX...MEG...LSX...DVN...LZK...SGF...DMX...EAX...TSA...
   
   36549417 36629497 37839507 39069359 40629234 41099165
   41159052 40499016 39089094 37769125 36469115 36489387