All flights in and out of Milwaukee were canceled until 12 p.m. Friday. However, there are back-up plans. One airline was bussing passengers to O'Hare.
The Amond family, for example, was to trying to fly from Milwaukee to Chicago for a funeral.
"Glad to be here and able to make it tonight. So yeah, it was nice they were able to accommodate us," Kate Amond told ABC7 Chicago.
The Amonds witnessed this storm first-hand in southern Wisconsin. In Jefferson, a storm chaser caught video of a funnel cloud.
"We just headed home the. They were telling us to stay at home and to not even do any traveling between Madison and Milwaukee. They said the roads were going to be terrible," Jeff Amond said.
In Waukegan, winds snapped tree branches, and there were power outages.
Downtown and throughout Chicago's south suburbs, heat will be the weather story throughout the day, but some residents say they are hearty and ready.
"It's hot out, but we're Chicagoans. We should be use to all this crazy weather. We get 30 below in the winter. We should be good with a couple hundred in the summer," Armando Medina said.
When asked what he was going to do to beat the heat, Mark Boyle said:
"Iced coffee, and I'll be going inside some air conditioning. But you know, it's better than 10 degrees, 20 degrees and so, I'll take it any day."