The National Storm Prediction Center has the Chicago area under a Marginal to Slight risk for severe storm development this evening into the overnight hours. Strongest severe storm activity is forecast over Missouri and west/central Illinois where an Enhanced to a Moderate risk of severe storms exists.
Warm moisture-laden air is flowing into the Chicago area on the wings of southerly winds gusting to over 30 mph this afternoon. At the same time, a cold front is advancing east out of the central plains and will be approaching our area later tonight. A band of strong to severe storms producing damaging winds, large hail, and possible tornadoes is expected to develop along and ahead of the advancing cold front. Strongest activity will likely occur during the peak heating daylight hours well to our west.
In the Chicago area with the storms hitting after sunset well into the evening and overnight hours the primary threats from the strongest storms look to be damaging winds in excess of 70 mph, large hail, vivid lightning and flood-producing downpours that could give an inch or two rainfall at some locations.