Severe weather timing: When to expect the worst storms and where in the Chicago area

Storms capable of bringing another threat of tornadoes and flash flooding are expected to hit the Chicago area Thursday, but when can you expect the worst and where?

The powerful system moving into the Midwest has left much of the Chicago area under an enhanced risk for severe weather, a level three out of five.

“This is pretty high for our area,” NBC 5 Storm Team Meteorologist Iisha Scott said.

Several waves of storms are expected with the potential for strong tornadoes.

Here’s a look at what to expect and when:

Storm Timing

As the morning commute gets underway, storms were already making their way into parts of the region, particularly areas north and west, though this line was not expected to reach severe limits.

Heavy downpours were reported on area roadways for commuters, however, and the rain led to a ground stop at O’Hare Airport, which was in place for departures headed to Chicago until at least 6:15 a.m.

This system is expected to move out of the region through the morning hours, leading to what Scott said would be a “bit of a lull” for the start of the afternoon as a warm front lifts north.

Then comes a line of showers and storms for the afternoon and evening.

A wind advisory is in place from 1-7 p.m. with gusts of up to 45 mph possible for much of the area.

In Kankakee County in Illinois and Lake, Porter, Newton and Jasper counties in northwest Indiana, the advisory is in place from 10 a.m. CT to 7 p.m., with gusts of up to 50 mph possible.

The main window for severe conditions looks to be between 3 p.m. and 9 p.m., Scott said.

The storms will continue into the late evening and overnight hours before tapering off in the early morning hours Friday.

Another round of storms will again be possible Friday night and through Saturday.

Are tornadoes possible and where?

All weather hazards are on the table, forecasters said.

Nearly the entire Chicago area sits under the enhanced risk category, however, a small line beginning north of Chicago along the lakefront down to southern Chicago suburbs and into northwest Indiana remained under the “slight risk” category, a level two out of five.

The highest risk for tornadoes sits west of Chicago.

“The main threats here will be damaging wind gusts and hail. There could be some strong, long-track tornadoes and I think that’s really what we’re going to have to watch,” Scott said.

Slowly, temperatures are expected to dip and the storms will come to an end late Thursday or early Friday morning.

When is the next round of storms?

Another round of potentially severe storms could be in store Friday, Scott said, with the threat for storms continuing into Saturday.

“There is another threat for strong to severe storms Fri afternoon/evening and possibly again on Sat.,” the National Weather Service wrote on X. “However, confidence in severe weather is low at this time due to uncertainties in frontal placement/timing.”

The storms would come as a warm front again lifts into the area, bringing temperatures into the 60s, “which could result in a narrow corridor where funnel clouds and tornadoes are favored,” the NWS warned.

Then a cold front again sweeps across the region, bringing the threat for storms, some potentially severe, Friday night and Saturday, though the timing of the front remains uncertain.