Winter storm's grip won't ease up until weekend

Keep off the roadways. Stay indoors. Brace yourself for more biting cold.

A unique winter snowstorm battering multiple Midwestern states could drop more than a foot of snow across the Chicago region over the next few days, experts warn.

Residents of Cook and surrounding collar counties should expect a few more days of pounding before any respite from the cold snap, said Matt Friedlein, a meteorologist with the National Weather Service.

While snowstorms aren't unusual for February, it's been six years since the Chicago region saw such sustained cold and heavy snowfall as we've seen since January.

This week's blizzard is exceptional because it stems from a convergence of lake effect snow - caused by cold air blowing over the warmer waters of Lake Michigan - and a severe weather system affecting parts of the nation that typically don't see much snowfall, Friedlein said.

Northern Illinois is under the grip of two major winter weather events: a cold air burst that began about 10 days ago originating north of the Arctic Circle and centered in the upper Midwest, and a significant winter storm moving in from the southern plains up the Ohio River Valley.

“It's a significant cold air dump for the middle of the country,” Friedlein said. “When it's this cold and it's snowing this much, that presents challenges for snow removal and treatment of roads. There's several layers ... the total snow, the rate (at) which the snow is falling, the cold temperatures ... all those things together add up to hazardous road conditions.”

Friedlein warned Tuesday morning's commute could be brutal, depending on how much snow falls and accumulates overnight.

Chicago's last major snowstorm was during the winter of 2014-15. That February was the coldest in 30 years with numerous days of subzero temperatures and several snow events.

“This significant snow event that we've seen in the past two weeks is noteworthy because we really haven't seen a stretch of frequent snowfall and sustained cold together,” Friedlein said.

Chicago region had received a cumulative 37 inches of snow this winter season through midnight Sunday.

“That is right at our normal (snowfall) for the entire winter. We've still got numerous weeks left,” Friedlein said.

Temperatures will ease up heading into the weekend potentially getting up into the lower- to mid-30s Sunday, which is a normal high for this time of year.

For daily snowfall totals by community, visit ncdc.noaa.gov/.