The SPC has released their first Moderate Risk for severe weather of the season for today:
The biggest risk will be for damaging winds along a squall line that is expected to form during the late evening to early morning hours just west and along the Mississippi River from southern Illinois southward into central Mississippi. 50-55 kt. winds in the 925-950mb level could mix down to the surface as the squall line pushes through. This is also a fairly good low CAPE/high shear setup for tornadoes, which could develop along the squall line.
The one thing to keep an eye on is the somewhat stable layer of air between the surface and 950mb, which will inhibit the potential severity for most of the storms except maybe in the southernmost areas.
I think the SPC prediction for today is fairly reasonable, but I will say that the northern extent of the Slight Risk and Moderate Risk could be cut back as the low-level air is forecast to be too stable north and east of southern Illinois. If the warm front associated with this system can get advected further north than forecast, then the SPC’s risk area could be justified. I could see that happening to a degree as the models often underforecast the northern extent of the warm sector in dynamically-strong cases such as this one, but I don’t think it will be as significant as the SPC appears to think it will be.