The National Weather Service (NWS) on Tuesday issued a tornado warning for the Chicago area, urging residents to immediately seek shelter as a series of thunderstorms is expected to bring strong winds and heavy rainfall.

The warning covers Will, DuPage, Cook and Lake counties and is expected to remain in effect through the mid-morning hours. A severe thunderstorm watch is also in place until 2 p.m. for northeast Illinois and northwest Indiana.

Meanwhile, departures from Chicago’s O’Hare International Airport have been temporarily halted due to the severe weather. The Federal Aviation Administration (FAA) has imposed a ground stop through 11:15 a.m., with the possibility of an extension depending on weather conditions.