A tornado watch is in effect Monday for more than two dozen Illinois counties, including Will County and parts of northwest Indiana.
Forecasters briefly issued a tornado warning for north central Kankakee County, but canceled it just before 9 p.m. when the storm weakened, the National Weather Service said.
A tornado watch remains in effect until 10 p.m. and covers south suburban Will County and Lake, Porter, Newton and Jasper counties in Indiana, according to the weather service. Other areas in eastern and central Illinois around Kankakee, Springfield and Champaign also are under the tornado watch.
The “potent autumn storm” could bring heavy rain and strong winds elsewhere in the Chicago area, although officials do not expect any widespread flooding, the weather service said.
The greatest possibility for severe weather is east of Intertate 55 and south of Interstate 80, and forecasters “cannot rule out an isolated tornado,” the weather service said. Damaging wind gusts up to 70 mph are possible.
A tornado watch means conditions are favorable for tornadoes and severe thunderstorms, according to the weather service. People in those areas should look out for threatening weather conditions and listen for possible severe weather warnings.
As of Monday afternoon, weather conditions were causing 30-minute delays at O’Hare Airport, where about 90 flights have been canceled, the city’s Department of Aviation said. At Midway, about two dozen flights were delayed an average of 20 minutes.