Editor's Note: The latest weather update for Tuesday, Jan. 9 can be found here. Our original story continues below.
When is the first snowstorm of the season expected to arrive in the Chicago area?
While a series of weather alerts take effect starting Monday evening, a second wave is still in store.
Here's a look at the timing for the upcoming system:
Monday evening
A winter storm warning will begin at 8 p.m. Monday for multiple Illinois counties while the rest of the Chicago area remains under a winter weather advisory.
Here's a look at alerts for various counties for this time:
Local
DeKalb, McHenry, Lake (IL), Kane and LaSalle counties: Winter storm warning from 8 p.m. Monday to 12 a.m. Wednesday.
Feeling out of the loop? We'll catch you up on the Chicago news you need to know. Sign up for the weekly Chicago Catch-Up newsletter here.
DuPage and Northern Cook counties: Winter weather advisory from 8 p.m. Monday to 12 a.m. Wednesday
Kendall, Grundy, Kankakee, Central and Southern Cook and Will counties in Illinois and Lake and Porter counties in Indiana: Winter weather advisory from 8 p.m. Monday to 12 p.m. Tuesday
Newton and Jasper counties in Indiana: Winter weather advisory from 8 p.m. CT Monday to 9 a.m. CT Tuesday
Kenosha County in Wisconsin: Winter weather advisory in effect from 9 p.m. Monday to 6 a.m. Tuesday.
Overnight into Tuesday morning
Snow is expected to develop Monday and throughout the overnight hours, when it will become more widespread, according to the NBC 5 Storm Team.
Expect mixed precipitation transitioning to snow between 10 p.m. Monday and 2 a.m. Tuesday. Peak snowfall rates for this wave is expected to arrive between 11 p.m. Monday and 5 a.m. Tuesday.
The overnight conditions are expected to impact morning commute times, though conditions will likely transition to rain for areas south and east of Chicago.
"Expect heavy snow rates & very poor visibility at times - wet snow is likely to cause significant impacts to Tue AM commute," the National Weather Service tweeted. "Plan for much longer travel times. Consider postponing travel if you have flexibility."
Snow totals through 6 a.m. Tuesday are expected to range between 2 and 5 inches, depending on location.
In Kenosha County, a winter storm warning begins at 6 a.m. Tuesday.
Illinois officials are urging drivers to "avoid unnecessary trips" and to use caution.
“Our team at IDOT spends the entire year preparing for snow and ice season, but the public’s cooperation is essential to ensure everyone’s safety,” Illinois Transportation Secretary Omer Osman said in a statement. “The safest option during winter weather always is to avoid unnecessary trips. If you are driving, expect travel to be slow and build plenty of extra time into your schedule throughout the week. Conditions may be dangerous at times. And please give our plows and trucks room to operate during any storm and after the snow has stopped falling.”
With dramatic shifts expected in snow totals across the area, the transportation department warned those who must travel that the "destination could have significantly higher amounts of snow than where your trip originated."
Tuesday morning and afternoon
Round two of the system will kick in during the mid-to-late morning hours Tuesday.
In this wave, snowfall totals are expected to increase in areas north and west of Chicago, with a "sharp snowfall gradient" dividing the precipitation between rain and snow.
Through the mid-morning hours, snow is expected to transition to rain in areas south and southwest, where overall snowfall totals are expected to be lower in the second wave.
Some areas could see more than eight inches of fresh snow in the late morning and into the afternoon, while others could see as little as one inch of snow in this wave. Where the dividing line will land will ultimately depend on temperatures, and some locations along the Interstate 55 corridor could see a mix of rain and snow.
In DeKalb and McHenry counties, anywhere from 7 to 11 inches of total accumulation is possible between the two waves of snowfall, according to the winter storm warning. In other counties under the warning, 5 to 8 inches of snow is expected.
A winter weather advisory ends at 9 a.m. for Newton and Jasper counties in northwest Indiana, and at 12 p.m. for Kendall, Grundy, Kankakee, Central and Southern Cook and Will counties in Illinois, and Lake and Porter counties in Indiana.
Tuesday evening
The snow is expected to continue into the evening hours Tuesday for some, while remaining rain for others.
Most alerts are scheduled to end at midnight Wednesday.
Another challenge could arise because of the wind, which will ratchet up Tuesday afternoon and into the evening, with gusts in excess of 30 miles per hour possible. That wind, along with any additional snowfall, could impact the evening commute, and could cause some untreated or elevated areas to develop ice, posing more travel issues.
The rest of the week
Additional rounds of snow are possible throughout the week ahead of an Arctic blast of air set to move in for the weekend and early next week.
