Chicago Weather

Timeline: What to Expect as Winter Storm Targets Chicago Area With Heavy Snow

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Winter storm warnings have been issued, and residents have been urged to take safety precautions ahead of a snow storm that could potentially dump a foot or more of snow on the Chicago-area in the next two days.

According to forecasters, rain that is falling across the area Tuesday will slowly transition to snow, and when it does it could potentially create traffic headaches on Wednesday and Thursday across the region.

The worst of the snow is expected to occur on Wednesday morning, leading to a snarled morning commute and hazardous travel conditions in numerous areas.

While the snow is likely to subside late Wednesday, some areas could see even more snow on Thursday morning, with an additional 2-to-5 inches possible in some locations.

Plow drivers across the Chicago area spent Tuesday preparing for the long work ahead as a snowstorm looms. Here's what it takes to get their trucks ready. NBC 5's Chris Coffey reports.

Here is the latest timeline of what we know about the coming storm:

Early Tuesday Evening

Rain that is falling across the area begins to transition to snow from west-to-east, with some western and northern suburbs already seeing mixed precipitation as of 6 p.m.

That trend will continue through the remainder of the evening, with temperatures ultimately cooling enough to allow snow to fall and for the winter storm to take hold.

8 p.m.: Winter Storm Warning Begins in Several Chicago-Area Counties

The first warning for the storm will take effect in DuPage, Cook, LaSalle, Kendall, Grundy and Will counties beginning at 8 p.m., and will remain in effect through 6 p.m. Wednesday.

The National Weather Service is calling for heavy snow and dangerous travel, especially Wednesday morning, and says that the snow will be heaviest in the southern portions of the warned area.

The heaviest snow in those areas is expected to occur in the early morning hours Wednesday.

Gov. J.B. Pritzker issued a disaster declaration Tuesday afternoon ahead, activating the Illinois National Guard, ahead of an anticipated severe winter storm.

10 p.m.: Winter Storm Warning Takes Effect in Kankakee County, NW Indiana

The areas forecasted to be the hardest-hit during the storm will start to see snow late Tuesday and into early Wednesday morning, with a winter storm warning taking effect in Kankakee County in Illinois, as well as Lake, Porter, LaPorte, Newton and Jasper counties in Indiana.

The National Weather Service says that by the time snow is done falling in those areas Wednesday evening that between 9-to-14 inches of accumulation may occur.

Early Wednesday

Snowfall rates in excess of one inch per hour are possible late Tuesday and into Wednesday morning, with the far southern suburbs starting to see that heavy snow around 2 a.m., according to forecast models and the National Weather Service:

That heavy snow could potentially continue after sunrise, impacting travel across the region and creating hazardous conditions.

Wednesday Evening

Snowfall will begin to taper off in some areas and may even stop completely, even in southern areas that are expected to be hard-hit by the weather.

By the time all is said and done, large accumulations are possible in areas in far northeastern Illinois and in the far southern suburbs, according to forecast models.  


Forecast models suggest that the snow will rev back up after midnight in Kankakee County and NW Indiana, but the exact tracking on the secondary portion of the system is still unclear.

An additional 2-to-5 inches of snow could fall in Kankakee County and NW Indiana by Thursday evening, but there is a possibility that the snow track could continue drifting to the southeast, meaning lower accumulations on the back half of the storm.

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