UPDATE: The winter storm has resulted in multiple spinouts and crashes, as well as a ground stop Monday morning at O’Hare International Airport. Downstate and central Illinois experienced worse winter conditions, and Washington County issued a shelter-in-place order due to “life-threatening weather conditions.” Our original story continues below.

A severe winter storm moving through Illinois and much of the Midwest hit parts of northeastern Illinois Monday morning, with snow and freezing drizzle expected to continue for some time through the day, the NBC 5 Storm Team said.

But not all areas will feel the storm’s impacts, said NBC 5 meteorologist Alicia Roman.

“The snow doesn’t affect everyone,” Roman said Monday morning. “Most of you will remain dry or clear, but some will see a lake effect snow cloud.”

According to the National Weather Service, a winter weather advisory was in effect for Lake, Cook and DuPage counties until 4 p.m. Monday. Lake effect snow was expected to continue in these areas during the morning and evening commutes.

Roman said the snow is expected to move into Lake and Porter counties in Indiana by Monday evening.

Snow timeline, road conditions

Counties in far northeastern Illinois were hit hardest by the storm early Monday morning, with more snow falling in Lake County and Kenosha County in Wisconsin, Roman said. Other areas also experienced freezing drizzle in places, resulting in an icy glaze on the roads.

According to Roman, the lake effect snow plume could strengthen at times in the late morning hours.

“During lake effect snow, weather can vary from locally heavy snowfall to dry weather just a few miles away,” the NWS warned. “Visibility conditions can also vary greatly. Be prepared for rapid changes in weather, visibility and road conditions.”

According to NBC 5 traffic reporter Kye Martin, the winter weather has already caused traffic jams and accidents in some parts, including the outbound lanes of I-290 in Austin, the northbound and southbound lanes of I-294 in Gulf, and roadways in the western suburbs.

“Roads, and particularly bridges and overpasses, are likely to become slippery and dangerous,” the NWS added. “Plan for slippery road conditions.”

By Monday afternoon, the snow was expected to impact mostly central and southern Cook County, Roman said, before spreading into northwest Indiana toward the evening.

How much snow could we get?

In some places the snow depth could be up to four inches, Roman said.

“We’ve already had a few inches of snow in Lake County,” Roman said, noting between two and three inches of additional snow could fall.

Most other areas will see between two and four inches, Roman said.

Conditions are expected to be mostly dry on Tuesday, Roman said, with the next best chance of snow coming on Friday.

Cold temperatures are expected to continue, Roman added, with highs in the 20s on Monday and throughout the week.