Rockford, Illinois – Flash flooding is already affecting parts of Winnebago County and is likely to worsen overnight as torrential rainfall continues across northern Illinois. Slow-moving thunderstorms could drop over two inches of rain per hour, especially in areas near and north of Interstate 80.
According to the National Weather Service in Chicago, the greatest flash flood threat runs from the Quad Cities to Rockford and into the Chicago metro. Flood-prone creeks and drainage areas could overflow rapidly, especially with repeated rounds of heavy rain expected through early Friday morning.
Areas of concern include Rockford, the northwest suburbs of Chicago, and rural counties near I-39 and I-88. Rainfall rates may exceed local drainage capacity, potentially stranding drivers or cutting off access to low-lying roads…