Severe Storm Watch Issued For Chicago Area

A severe thunderstorm watch has been issued for most of the Chicago area until midnight Wednesday. The watch is in effect for Boone, Carroll, Cook, DeKalb, DuPage, Jo Daviess, Kane, Kendall, Lee, Lake, McHenry, Ogle, Rock Island, Stephenson, Whiteside, Will and Winnebago counties.

Severe storms are expected Tuesday afternoon, continuing through the evening and ending overnight, according to the National Weather Service.

Storms will most likely start around 4 p.m., and end at 1 a.m. Wednesday morning. According to the weather service, a front is expected to set up right along or just south of I-80. The main tornado threat is south of the front.

"The main threats are large hail and flooding for areas north of I-80," the weather service said on its Facebook. "All severe weather hazards are possible along and south of Interstate 80, including the possibility for strong tornadoes."

On its Facebook page, the weather service said a "rule of thumb" for if you're in the threat zone is "if it feels like summer" at 6 or 7 p.m. Tuesday. If it's chillier at that time, then the threat zone is south of you.

There is a level 3 of 5 tornado risk for areas near and south of I-80, a level 3 of 5 large hail risk, and a level 2 of 5 damaging wind risk.

The NOAA's storm prediction center has updated a part of the area to a moderate risk (4 out of 5), primarily south of I-80, the weather service shared.

"As we continue to assess the progress of the front and where it ultimately stalls this afternoon, we'll be able to better refine the area of greatest concern for damaging tornadoes," the weather service said.

Locally heavy rainfall is also possible late Tuesday afternoon, and could cause localized flash flooding, according to the weather service. Colder temperatures move in to the area after Tuesday, with rain continuing Wednesday morning.