Convective initiation occurred shortly after 4 pm from central Illinois into northwest Indiana in response to a secondary mid level shortwave trough ejecting out of central Missouri and increasing forced ascent. 18Z special sounding from Lincoln Illinois (KILX) showed dramatic mid level cooling as a result of the ejecting mid level shortwave trough. Rapid scan visible imagery showed aggravated CU/TCU development by late afternoon with continued surface based destabilization and low level moisture advection within mid level dry slot left behind lead shortwave trough which spawned widespread showers and thunderstorms earlier in the day. An unseasonably strong upper level wind maxima associated with this ejecting trough and backing surface flow led to extreme deep layer wind shear. Several broken lines of discrete supercells developed in the evening although the storm responsible for this tornado developed toward the end of the event. Numerous storms exhibited intense low level...