A Flash Flood Watch is in effect for all but the northernmost counties of the Chicago area through Wednesday morning.
Area soils have been saturated due to resent widespread rainfall, setting the stage for rapid runoff of subsequent rains during the next 24 hours.
Since Saturday, there has been 3.02″ of rain recorded at O’Hare, and 3.50″ recorded at Midway. For comparison, normal totals for the entire month of April are 3.38″.
Additional waves of thunderstorms through the overnight hours into Wednesday morning will generate heavy flood-producing downpours on the order of one to three inches, giving a threat of localized flash-flooding, as well as causing significant rises on area rivers and streams.
The following counties in Illinois and Indiana are under the Flood Watch through Wednesday morning:
In Illinois, Lee, DeKalb, Kane, DuPage, Cook, LaSalle, Kendall, Grundy, Will, Kankakee, Livingston, Iroquois and Ford.
In Indiana, Lake, Benton, Jasper, Newton and Porter.