Thursday, June 22, 2017
Thursday Evening Storm Threat
10:00pm Update: Showers and thunderstorms are beginning to increase in coverage late Thursday evening. The overall severe threat will remain low, however, an isolated strong wind gust can't be ruled out. Of greater threat may be the heavy rain potential. Moisture values in the atmosphere are over one inch. This means thunderstorms will be very efficient at producing heavy rainfall. Individual thunderstorms west over Iowa have had a hail and wind threat associated with them, but as they move that will shift to heavy rainfall.
An isolated thunderstorm or two is possible through sunset, but the majority of the evening will remain dry. A cold front draped over Wisconsin will begin to sink south Thursday night and early Friday morning, not completely passing northern Illinois until after sunrise Friday.
Cold front passes by Friday morning, ending the chance for rain. It'll still feel muggy during the morning, but drier air arrives after 10am and should make Friday afternoon and evening feel much more comfortable.