Update 1:30PM CDT…
The portion of the Chicago area along and north of Interstate-80 has been upgraded to a Slight Risk for severe thunderstorms late this afternoon into the evening hours.
Update 8AM CDT…
The National Storm Prediction Center has updated their severe weather outlook map below…they now have a portion of Wisconsin under an Enhanced Risk of storms (30% chance of severe storms within 25 miles of a given location) with the area along the Illinois-Wisconsin state line in a Slight Risk (15% chance of severe storms within 25 miles of a given location). The portion of the Chicago area along and north of Interstate-80 remains in the Marginal Risk (5% chance of severe storms within 25 miles of a given location).
A band of strong to potentially severe thunderstorms may spread out of northwestern Illinois and Wisconsin across our area late this Thursday afternoon and during the evening hours. The strongest storms could produce damaging winds and large hail.
What meteorologists term a “mesoscale convective system” will move out of the Dakotas into Minnesota and northern Iowa this morning. Carried eastward by a short-wave upper-level disturbance. This complex of thunderstorms will likely continue to track east-southeast across our area this evening, potentially impacting primarily the portion of our area north of Interstate-80.
The National Storm Prediction Center has outlooked northern Illinois in a Marginal Risk (green-shaded area on the severe weather outlook map below) for severe storms with Wisconsin and northeastern Iowa as well as southeastern Minnesota in a higher Slight Risk (yellow-shaded area) category.