Flood-producing thunderstorm downpours likely across northern Illinois into northwest Indiana next 24 to 36 hours

With a nearly stationary west-east oriented frontal boundary in place over our area, periodic bands/clusters of thunderstorms will develop and move east across northern Illinois into northwest Indiana during the next 24 to 36 hours. Heavy rainfall in excess of an inch/hour, in some locations repeatedly “training” over the same location will produce flooding.

The National Weather Prediction Center has included the entire Chicago area in a Slight Risk of Excessive Rainfall today and tonight (Yellow-shaded area on the highlighted map depicting a 10 to 20 percent chance of flood-producing rains within 25 miles of a given location).

This Tuesday morning a wave of showers and thunderstorms looks to move east across southern Wisconsin and northern Illinois adjacent to the Illinois-Wisconsin border, tracking over the same area that was hit with 2 to 5-inch rainfall totals yesterday into the overnight hours – portions of Winnebago, Boone and Ogle Counties remain under a Flood Warning until noon CDT. Especially hard hit was the immediate Rockford area where extensive flooding continues.

Afternoon heating should increase the probability of additional thunderstorms that will carry into the evening/overnight hours tonight. In a few of the strongest storms damaging winds could occur. Access the Interactive Radar Display and the radar map below for a better idea of heavy rainfall location.

Latest Regional Weather Radar Mosaic…

Central Great Lakes sector loop