The weather service says strong to severe thunderstorms are possible and could bring destructive hail and a tornado to the Chicagoland area on Thursday.
The National Weather Service (NWS) on Wednesday issued a hazardous weather outlook for Lake, McHenry, Winnebago, Kane, Cook, Will, DuPage, Boone, Ogle, Lee, DeKalb, LaSalle, Kendall, Grundy, Kankakee, Livingston, Iroquois and Ford counties.
The outlook said isolated to scattered thunderstorms may develop ahead of a cold front late Thursday afternoon and shift east-northeast into the evening.
The NWS said that if thunderstorms develop, some will likely become severe with damaging to destructive hail being the greatest threat.
There may also be a damaging wind threat and a tornado threat with some storms, the outlook said.
Hot and dry conditions and gusty southwest winds behind a cold front late Thursday afternoon into the early evening may bring a brief period of elevated fire danger for portions of northern and central Illinois.
The outlook said strong west-southwest winds and very warm and dry conditions will result in potentially significant fire danger on Friday.
A few thunderstorms with the potential for locally damaging winds “cannot be ruled out” late afternoon and early evening on Friday.
A graphic from the weather service showed a three out of five level for severe weather threat in Lake County and McHenry County, along with much of the immediate Chicago area.
The NWS said it is still uncertain whether storms will form and their coverage. “There may just be one or two storms in all. If storms form, they will likely become severe.”
Residents are urged to have multiple ways to get weather warnings and take shelter if a warning is issued.