Risk of severe storms this evening/overnight
There is a Marginal to Slight risk (green and yellow-shaded areas respectively on the headlined map) of severe thunderstorms moving into the Chicago area from the south and west late this Wednesday afternoon into the overnight hours. Damaging winds and large hail will be the main threat.
A center of deepening low pressure will track northeast through Iowa today and Wisconsin tonight. The associated warm front will shift north out of central Illinois, passing through the Chicago area this afternoon, bringing warm increasingly more moist air into our area – there could be a few showers associated with this frontal boundary.
Then as the low moves into Wisconsin later in the afternoon, the associated cold front will swing through Illinois from the west, triggering a line of strong to severe thunderstorms that will approach our area with the storms expected to hit here during the evening. Another surge of showers/thunderstorms may move through late tonight/early early Thursday as the cold front passes.