Some parts of the Chicago area have already seen several inches of snow this week, but another significant system is eyeing the region before the end of the week.
While snow total projections continue to fluctuate in the lead-up to the system, models are clear that accumulating snow is likely.
Already, parts of the area are under a winter storm watch from Thursday evening through Saturday morning.
That includes McHenry, Lake, Kane, DuPage, Kankakee, Cook and Will counties in Illinois and Lake, LaPorte and Porter counties in northwest Indiana.
Some, including DeKalb and LaSalle counties, will see the watch take effect Thursday evening.
It will mark the third system this week after the season's first snowstorm arrived on Tuesday and another round of light snow is possible overnight Wednesday and into Thursday.
Much like Tuesday, the storm set to arrive Friday and Saturday will have a rain-snow component to it, meaning there could be a sharp cutoff line in snow totals. What remains unclear, however, is where that line will set up.
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The storm's strength and track are still developing, but "several inches of accumulating snow in combination with strong winds" could result in difficult travel across the area into Saturday, the National Weather Service said.
The snow is expected to arrive in the Chicago area Friday morning, with the brunt of the storm expected to hit Friday afternoon and evening, with threats of major travel impacts to the evening commute.
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"The strongest winds with the potential for periods of blizzard conditions are expected Friday evening into early Saturday," according to the winter storm watch.
Models Wednesday morning indicated parts of northeastern Illinois and northwest Indiana could see 6 inches of snow or more, according to NBC 5 Storm Team Meteorologist Alicia Roman. Similarly, the winter storm watch warns of totals of 6 inches of more.
The Weather Prediction Center currently lists much of northern Illinois and northwest Indiana under a 70% probability of 4 inches of snow or more. That number drops to 40% for 8 inches of snow or more.
"Still to early to say but we will continue to watch and monitor and keep you posted on what we can expect as we get closer," Roman said.
Much colder air will spread across the region beginning Sunday, producing potentially dangerously cold wind chills, Roman said.
The cold, arctic mass could result in "ice jam-related flooding" in some parts early next week, the NWS said.
By next week, the "coldest air of the season is expected to arrive," the NWS said, with wind chills in the negative teens or even 20s at times.
Roman reported a high of 9 degrees Sunday, with temperatures dipping to a high of 3 degrees Monday, and 6 degrees Tuesday.
The NBC 5 Storm Team is tracking this forecast as it develops. Stay tuned for updates as each system approaches.