MESOSCALE DISCUSSION 2407
   NWS STORM PREDICTION CENTER NORMAN OK
   1221 PM CDT FRI SEP 26 2003
   
   AREAS AFFECTED...NRN MO/CNTRL IL
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 261721Z - 261915Z
   
   CONVECTIVE INITIATION AND SQUALL-LINE DEVELOPMENT IS EXPECTED TO
   OCCUR OF THE NEXT FEW HOURS ACROSS WRN AND NRN MO. THE STORMS WILL
   BE CAPABLE OF PRODUCING WIND DAMAGE...LARGE HAIL AND ISOLATED
   TORNADOES AS IT MOVES EWD INTO WRN IL. A WW WILL LIKELY BECOME
   NECESSARY IN THE NEXT HOUR OR SO.
   
   STRONG MOISTURE ADVECTION IS OCCURRING ACROSS NRN MO WHERE SFC
   DEWPOINTS HAVE RISEN SHARPLY IN THE LAST 3 HOURS. SFC DEWPOINTS HAVE
   REACHED THE MID TO UPPER 60S F AND MLCAPE VALUES HAVE RISEN TO
   AROUND 1000 J/KG IN THE KANSAS CITY AREA. STORMS ARE ALREADY ONGOING
   ACROSS NRN IL IN A REGION OF LOW-LEVEL WAA WHERE INSTABILITY IS
   INCREASING...AND ADDITIONAL STORMS SHOULD DEVELOP ACROSS NRN MO IN
   THE NEXT 1-2 HOURS AND MOVE QUICKLY E/SEWD AHEAD OF A COLD FRONT.
   ALTHOUGH CONVECTION COULD BE SUPERCELLULAR EARLY...A TRANSITION TO A
   SQUALL-LINE SHOULD OCCUR DURING THE AFTERNOON. AS THE CONVECTION
   MATURES...THE STRONG DEEP LAYER SHEAR AROUND 50 KT AND STRONG
   DIRECTIONAL SHEAR WILL MAKE SCATTERED ORGANIZED SEVERE STORMS
   LIKELY. CONSIDERING THE AMOUNT OF SPEED SHEAR IN THE LOWER-LEVELS
   COMBINED WITH STRONG LARGE-SCALE FORCING...THE SQUALL-LINE WILL HAVE
   A POTENTIAL FOR WIDESPREAD WIND DAMAGE. A PLUME OF STEEP LAPSE RATES
   STRETCHING ACROSS NRN MO WILL CREATE A POSSIBILITY FOR LARGE HAIL.
   STRONG 0-1 KM SHEAR VALUES AND LOW LCL HEIGHTS WILL ALSO MAKE
   ISOLATED TORNADOES POSSIBLE ACROSS NRN MO...ERN MO AND CNTRL IL.
   
   ..BROYLES.. 09/26/2003
   
   
   ATTN...WFO...LOT...ILX...LSX...DVN...SGF...EAX...
   
   38079339 38129416 38559459 39439477 40079345 40789149
   41368942 40828868 39718873