A Tale of Two Forecast Models: Midweek Storm Could Bring Rain, Heavy Snow to Chicago Area

Wintry weather is expected to arrive in the Chicago area midweek, but it's unclear what track the storm will take

NBCUniversal Media, LLC

The Chicago area is going to see a rapid warm-up in temperatures on Tuesday and Wednesday, with highs reaching into the 50s by Wednesday, but that will be accompanied by a weather system that’s going to bring rain, sleet and eventually snow to the region.

The big issue at the moment is tracking what kind of precipitation will be falling when, and how much of it the region can expect.

The two models that the NBC 5 Storm Team uses to predict the tracks of storms, the “Global Model” and the “European Model,” show widely divergent paths for the storm, with one indicating that a foot or more of snow could fall in Chicago and numerous suburbs, while the other is pointing to more significant snowfall accumulations in central Illinois and Indiana, with the Chicago area largely remaining unscathed.

What We Know So Far

Before the snow arrives, the area will likely see heavy rain on Wednesday, with localized totals of 1-to-2 inches of rain possible in some locations.

That heavy rain could cause flooding in low-lying areas, and ice jams on area rivers and streams could break up because of the heavy rains and the above-average temperatures.

That rain will eventually transition over to a wintry mix, which could lead to hazardous travel conditions on Wednesday night and into Thursday morning, and by the time Thursday morning rolls around, snow is expected to fall across the region.

That is where the models come into play.

What the Global Model Says

The Global Model currently shows a forecast track for the storm that will carry the heart of it through the northern part of Illinois, with the northern and western suburbs potentially getting hammered by a foot or more of snow thanks to lake-enhancement.

The city of Chicago itself could see more than a foot of snow in some locations, with more than 14 inches of snow possible at O’Hare.

By contrast, areas in the far southern suburbs would see significantly less snow under the path projected by this model, with Kankakee County and parts of northwest Indiana seeing perhaps 2-to-3 inches of snow from the storm.

What the European Model Says

The European model indicates a way less impactful snowfall in the northern and western suburbs, but areas to the far south, including Kankakee County, could be hit by 6-to-8 inches, or more, of snow if the system travels farther to the south as it makes its way into the Midwest.

Parts of northwest Indiana would also see significant snowfall, with the central portions of both Illinois and Indiana potentially seeing a foot or more of snow under the track targeted by this model.

The city of Chicago and the northern and western suburbs would likely see small accumulations if this track were to unfold.

Contact Us