Risk of severe thunderstorms across the Chicago area later this afternoon/evening

Update 11:45AM CDT…

The National Storm Prediction Center has adjusted the severe storm risk area slightly south, but most of the Chicago area remains in the Slight to Marginal Risk. The best chance for severe storms here remains late afternoon into the overnight hours with the highest risk area just south and west of Chicago.

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The National Storm Prediction Center has the entire Chicago area under a Slight to Marginal Risk of severe thunderstorms later this Wednesday afternoon into the overnight hours. The best chance for severe storms appears to be just south and west of Chicago. Damaging winds and large hail are the main threat, but a tornado or two could occur.

A Slight Risk (yellow-shaded area on the highlighted map) depicts a 15% chance of severe storms within 25 miles of a given location, and a Marginal Risk (green-shaded area on the highlighted map) depicts a 5% chance of severe storms within 25 miles of a given location.

A warm front will be oriented west-east across central Illinois this afternoon with an eastward-moving center of low pressure and cold front approaching out of the central plains (see map below). With strengthening southerly flow over Illinois, warm moist air will overrun the warm front and the approach of the low pressure/cold front during the peak-heating hours of the day acting as a trigger will further destabilize the atmosphere, enhancing the prospects of severe thunderstorm development later this afternoon into the evening hours.

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