Enhanced risk of severe weather has been expanded by the SPC further north and east through Missouri, western Illinois and southeast Iowa. The main threats will be strong winds (up to 70 mph) and hail. The potential for tornadoes exists, with the higher risk in southern Missouri.
Check out this animation of the HRRR (High-Resolution Rapid Refresh) model. Storms initiate around 5-6 pm with some individual cells for a few hours (a short window). If any of those cells can strengthen and rotate, then some isolated tornadoes will be possible.
The storms then end up linear and could still pose a damaging wind threat after 8pm in eastern Iowa and western Illinois.
There are a few negatives to the severe risk, which are the clouds right now and a few showers and storms moving through eastern Iowa right now. IF the atmosphere can recover, then the severe threat is still on. Here's a visible satellite image from 11:50 am:
That clearing will continue moving east over the next few hours. If the sun is out long enough (before storms start up) and temperatures can recover, then there will be enough instability for a few severe storms. Where the sun has been out... temperatures have shot up:
Still, the dew points have a way to go and because of the set up, the probability for tornadoes is lower than last week. The warm front and low pressure (where you typically see the greatest tornado risk) will be clear into Minnesota. However, there is enough wind shear (rotation) in the atmosphere that the potential for tornadoes still exists.
Here's the tornado probabilities from the SPC:
Where the hash marks are, that's where the highest potential exists for tornadoes, which includes Springfield and Columbia, Missouri. Overall, later on this afternoon it could get interesting for the second time this year in the Midwest.