(10:00AM - 7/23/21) A storm system is expected to move through the region on Saturday, bringing severe t'storm potential to portions of the state Saturday afternoon into Saturday night.
A storm system will move across the Northern Plains today, then pushing eastward across the Midwest and Great Lakes on Saturday. This storm system will bring severe t'storm potential to portions of the state, Saturday afternoon into Saturday night. Model guidance has been showing some potential for this period for a few days now. The main questions as of now are storm coverage, and how far reaching severe potential will be.
Saturday Afternoon - Saturday Night, July 24th...
In the wake of a few isolated showers and t'storms Saturday morning across Northern Illinois, ample clearing and destabilization is expected. Development of scattered showers and t'storms is expected Saturday afternoon along a southeastward advancing cold front, across Southern Wisconsin and Northern Illinois. This activity will then push southward across Northern and portions of Central Illinois, Saturday afternoon into Saturday night. An environment will be in place supportive of a severe t'storm risk with some of this activity. This environment will feature moderate instability of 3,000-5,000J/KG, dew points in the low to upper 70's, decent shear, decent forcing, and poor lapse rates of 5.0-6.0C. This environment will be supportive of upwards of an isolated severe t'storm risk (level 1) across portions of Northern and Central Illinois. Damaging winds and hail will be the severe weather threats, though an isolated tornado can't be ruled out.
Below is the severe t'storm forecast for this event.