Tornado watch, wind advisory in Chicago area ahead of severe storms; flooding snarls road to O'Hare Airport
The Chicago area is facing rounds of afternoon and evening severe weather, bringing storms that could produce hail, wind damage, flooding and tornadoes.
A Tornado Watch is in effect for Boone, DeKalb, Grundy, Kane, Kendall, LaSalle, Lee, McHenry, Ogle and Winnebago counties until 8 p.m.
A Wind Advisory is in effect for Cook, DeKalb, DuPage, Will, Grundy, Kane, Kankakee, LaSalle, Lee, Livingston, Iroquois, Ford, Kendall and Lake counties in Illinois and Benton, Jasper, Lake, Newton and Porter counties in Indiana until at least 7 p.m.
Intermittent flooding on I-190 on and near the ramp from Mannheim Road O'Hare International Airport has caused problems all day long. It took crews hours to clear a storm drain and make the ramp passable Thursday morning and by afternoon inbound I-190 was down to one lane near the exit. Crews are working to clear it again, but the airport advises anyone who is flying today to either allow extra time or consider taking the CTA Blue Line or other public transit to the airport.
There is also a ground delay in effect at O'Hare due to the morning storms, with delays averaging more than six hours as of 3:30 p.m. Those delays are expected to persist through the rounds of storms and could last into the early morning hours.
Warmer air that came int he late morning and afternoon supports the potential for strong to severe thunderstorms, with threats including damaging winds, hail, heavy rainfall, and a threat of tornadoes.
Almost the entire Chicago area is under a 3/5 or moderate risk for severe storms Thursday. The risk for tornadoes is between 5% and 15% for most of the area.
Prediction models indicate that two separate rounds of thunderstorms are likely. The first round had already begun developing by 12:50 p.m. in Western Illinois, and will move east through the afternoon. They may struggle a bit at first, as our atmosphere is still a little too stable for severe storms, but they could grow in intensity as the atmosphere warms through the afternoon.
Isolated supercells that could prompt tornado warnings are possible after 3 p.m.
The second round of storms, expected to approach the I-39 corridor sometime after 7 p.m. or 8 p.m., are likely to be stronger and will include supercells capable of producing tornadoes. There is some indication that sunset could weaken those storms a bit by reducing the atmospheric instability, but it's not guaranteed.
However, conditions are not in line with the March 10 storms that produced deadly tornadoes in Kankakee, Illinois, and Lake Village, Indiana.
The greater Chicago area has already seen its fair share of severe storms this year. Just last month, the National Weather Service confirmed 12 tornadoes across Illinois and Indiana.
Tornadoes have always been an issue in the Chicago area, but activity has been intense in some recent years. In the summer of 2024, more than 30 tornadoes touched down across the Chicago area in one day.
In west suburban Aurora, public works employees spent the day preparing for the severe weather. City crews swept streets and cleared clogged drains and storm sewers so that the coming rainfall and storm damage would not be compounded by existing conditions.
Water and Sewer Department worker Crispin Paustian said debris gets into the storm drain system during the winter, causing clogs and backups. And that work will continue during and after the storms, too.
"Sometimes it happens in random places. It's never the same place," he said.
Homeowners have a part to play in storm preparation too.
"If there's a drain in front of your house and you see the leaves on it before it starts raining, you can clean them off," he said. "I mean, that would help tremendously."
The White Sox home opener against the Toronto Blue Jays has also been postponed due to the weather Thursday. The game has been rescheduled for Friday afternoon, and anyone who paid for a ticket for parking can use it on Friday.
