A rather interesting and perhaps surprise event may be setting up across portions of Illinois tomorrow ahead of a cold front/strong low pressure system. Some of the latest HRRR guidance and 3km NAM is showing CAPE values around 3000 J/KG ahead of the frontal boundary tomorrow. Most of the winds ahead of this front look fairly veered however there is an area in West Central to Central Illinois that look to back slightly between 18z and 21z and this coincides with when the HRRR is showing some semi-discrete thunderstorm development in the area in a somewhat favorable environment. I was surprised to see on both the HRRR and the 3km NAM, 0-1km SRH values in the 150m2/s2 range with 0-3km values slightly higher, this was pegging the significant tornado index a little higher ahead of these cells. Here is a sounding I pulled around 19z just west of Peoria, IL ahead of that line of cells. Again the wind profile is fairly uni-directional, but there is some low level helicity to work with, especially if we can maintain a semi-discrete storm mode. While obviously not the greatest setup in the world, its worth watching, especially if any overnight convection can leave an outflow boundary which locally backs winds. I've seen days like this that didn't look significant before-hand and turn into a locally significant event because of a couple minor details. One of the more recent events I remember is November 22, 2010. I barely missed a tornado chasing that day, hoping for a repeat tomorrow would be like finding a diamond in a pile of dirt though lol. Regardless, I'll be watching it.