A flood watch is in effect for a number of Central Illinois counties and will last until Sunday. Courtesy the National Weather Service, flooding caused by excessive rainfall is possible for portions of the following Central Illinois counties: This flood watch for these counties was put into effect at 1:45 p.

Thunderstorms will last through the evening, and then on Sunday, hot temperatures will return, with the heat index between 100 and 105 degrees. A flood watch is in effect as a threat of severe storms is expected by the afternoon for the Chicago area.