The National Storm Prediction Center has northeast Illinois and northwest Indiana in a Marginal to Slight Risk of severe thunderstorms (green and yellow-shaded area on the highlighted map above displays a 5 to 15% chance of severe storms within 25 miles of a given location) primarily later this Thursday afternoon and during the overnight hours tonight.
Damaging winds and large hail along with flood-producing downpours look to be the main threats with these storms.
In addition the National Weather Prediction Center has the entire Chicago area primarily in the Slight Risk area (see map below) for Excessive Rainfall during the next 24 hours – again the main threat for flood-producing downpours of 1 to 3-inches rainfall is projected to be later this afternoon and the overnight hours.
A center of low pressure and its associated cold front will move out of Nebraska, tracking east-northeast through Iowa today and northern Illinois/southern Wisconsin tonight preceded and accompanied by bands/clusters of strong to severe thunderstorms, some of which may even produce tornadoes. The greatest threat for severe storms will be in Iowa and Missouri this afternoon/early evening (tan-shaded enhanced area on the headlined map).
These storms will move into Illinois and western portions of the Chicago area later this afternoon/early evening and continue during the overnight hours tonight, gradually ending from the west, as the cold front passes through our area later tonight/early Friday morning.
Excessive rainfall outlook Thursday/Thursday night...