SPC MESOSCALE DISCUSSION 0601 FOR NERN AND E CNTRL MO...CNTRL/SRN
   IL AND SWRN/W CNTRL IN
   CONCERNING...SEVERE THUNDERSTORM WATCH 194...
   
   VALID 011857Z - 012100Z
   
   THREAT FOR LARGE HAIL CONTINUES WITH CLUSTER OF SUPERCELLS MOVING
   EWD THROUGH CNTRL/S CNTRL IL. NRN STORMS STILL APPEAR ELEVATED.
   HOWEVER...THERE IS SOME CONCERN THAT STORMS MOVING THROUGH S CNTRL
   IL MAY BECOME SURFACE BASED WHICH WOULD SUGGEST TORNADO THREAT MAY
   INCREASE. PORTIONS OF WW 194 MAY NEED TO BE UPGRADED TO A TORNADO
   WATCH WITHIN THE NEXT HOUR OR SO.
   
   CLUSTER OF SUPERCELLS ARE EXPECTED TO CONTINUE THROUGH IL N OF
   SURFACE WARM FRONT THAT EXTENDS EWD FROM A SURFACE LOW IN SWRN MO
   THROUGH S CNTRL IL. ACTIVITY WILL EVENTUALLY SPREAD EWD INTO IND.
   STRONG PRESSURE FALLS HAVE DEVELOPED OVER IL AND WARMER/MOISTER
   BOUNDARY LAYER AIR CONTINUES TO SPREAD NEWD ALONG SWLY LOW LEVEL
   JET. AS BOUNDARY LAYER CONTINUES TO MOISTEN/DESTABILIZE...SOME
   STORMS ON SRN EDGE OF CLUSTER MAY BECOME SURFACE BASED. GIVEN
   STRENGTH OF LOW LEVEL AND DEEP LAYER SHEAR WITH 0-3 KM STORM
   RELATIVE HELICITY IN EXCESS OF 300 M2/S2...THREAT FOR ISOLATED
   TORNADOES WOULD INCREASE.
   
   ..DIAL.. 05/01/02