Portions of Cook County spent Tuesday night under a tornado warning while the city remained under a severe thunderstorm warning following a day of temperatures so warm they nearly broke city weather records.
The city’s Office of Emergency Management and Communications issued a severe storm warning at about 7:15 p.m., which was expected to last until 9 p.m., while the National Weather Service forecasted quarter-sized hail and wind gusts of up to 70 mph for the area under the severe storm warning.
As thunder and lightning flashed throughout the evening over the city and suburbs, hail blanketed some city neighborhoods and suburban communities. On social media, users reported tornado sightings, but weather services hadn’t confirmed any touchdowns.
ComEd reported about 8,500 power outages around 8:40 p.m., with the majority being located in the Northwest and western suburbs.
The storm area reached from the Indiana state line to southwest suburban Joliet and up north to Mundelein.
The weather service also issued a tornado warning for much of north Cook County through 8:30 p.m. Tuesday.
A tornado watch means weather conditions make tornado formation likely. A tornado warning means that a tornado has been sighted.
The severe weather led to a ground stop at O’Hare International Airport in effect after 8:30 p.m. and traffic management at Midway Airport, according to the Federal Aviation Administration.
Just before 8 p.m., Metra cautioned riders to prepare for “extensive delays” along the Union Pacific Northwest lines due to the tornado warnings in north Cook County, with outbound trains stopped near Barrington.
Earlier on Tuesday, temperatures reached 74 degrees just after 3 p.m. at O’Hare International Airport, the city’s official recording site, missing out on the record by one degree. David King, a meteorologist at the National Weather Service in Romeoville, said the daily record for Feb. 27 was in 1976, when temperatures topped out at 75 degrees, also marking the warmest day in the entire month of February on record.
Chicago Tribune’s Sarah Freishat contributed.