Temperatures will plummet to dangerously low levels overnight as snowstorms that began overnight are expected to dump up to 6 inches of snow in some parts of northern Illinois by the time they finish Tuesday morning.
Snowfall Sunday morning accumulated to between 1 and 3 inches by late afternoon, when the precipitation largely stopped, according to the National Weather Service.
By 6 p.m. Sunday, 2.2 inches of snow had fallen at O'Hare since midnight, according to the weather service.
Temperatures fell into the teens by evening Sunday, then dropped into single-digit lows for the area, according to the weather service, which declared a wind chill advisory for northern Illinois from midnight Sunday through noon Monday.
Wind chills are expected to drop to 15 to 30 below zero overnight, leading to the risk of anyone going outside suffering frostbite within minutes, according to the weather service.
Sunday's weather caused disruptions for air travel. Both O'Hare International Airport and Midway Airport reported delays, and 235 flights out of O'Hare had been cancelled Sunday as of 8:30 p.m., according to the Chicago Department of Aviation.
Monday night, a snowstorm awaits Chicagoans and other residents of northern Illinois, bringing between 3 and 6 inches in most places, on top of Sunday's snow, according to the weather service. The weather service has declared a winter storm watch, effective Monday night through early Tuesday.
The snowstorm Monday is expected to start between 6 and 9 p.m. and finish sometime Tuesday morning, National Weather Service meteorologist Ben Deubelbeiss said.
Monday evening, possibly at the tail end of rush hour, the snow may fall fast enough that snowplows will have difficulty keeping up, according to the weather service.
"It'll be white powdery snow," Deubelbeiss said. "The roads might still be pretty messy on Tuesday."
Frigid temperatures are expected to persist through the week, with high temperatures only reaching the low double digits on Tuesday and dipping again Tuesday night below zero. Wednesday, highs may not get above zero, with lows possibly hitting 13 degrees below zero in the suburbs and 5 to 9 below zero downtown.
