Summer-like temperatures and possible severe thunderstorms in the Chicagoland area Tuesday will give way to frigid temperatures and snow overnight into Wednesday.
The National Weather Service (NWS) issued a hazardous weather outlook for portions of north central Illinois and northeast Illinois Tuesday morning.
The outlook includes Lake and McHenry counties as well as the rest of the Chicagoland area.
Scattered thunderstorms are likely Tuesday evening, with some that could become severe, the outlook said.
The primary severe risk will be large hail, possibly up to two inches in diameter.
Locally damaging winds over 60 mph and a tornado or two are possible Tuesday evening, the outlook said.
Strong northwest winds are likely late in the evening and overnight behind a strong cold front.
Frequent gusts of 30 to 40 mph are expected with brief gusts over 50 mph possible.
The powerful cold front will race quickly across the area Tuesday evening and produce a 20-30-degree temperature drop in just an hour, the NWS said.
Wind chills as low as five degrees below zero could occur in certain areas of northern Illinois.
“The temperature change between this evening and sunrise Wednesday will be nothing short of dramatic!” the NWS said. “After summer-like temps in the 70s today, tomorrow morning’s wind chills near or below zero will feel absolutely brutal!”
Snow showers are likely after midnight. Some areas could see an inch of accumulation and hazardous travel conditions.
“There is still a lot of uncertainty regarding how much, if any snow will occur tonight,” the NWS said, adding that if snow falls it will likely lead to roads becoming hazardous.