A second push of accumulating snow is still expected to hit part of the Chicago area Tuesday following hours of snowfall, rain and wind overnight.
The wave could still bring several additional inches of accumulation, though a sharp gradient will mark a dramatic shift in totals for those who see snow and those who see rain.
As of Tuesday morning, nearly all of the Chicago area was under either a winter weather advisory or a winter storm warning, with threats of heavy, wet snow, high winds, low visibility and dangerous travel conditions expected to last throughout the day.
MORE: Are Chicago-area schools closed today? Check school closures due to snow here
Some areas overnight, including counties to the south and east, saw upwards of four inches of snow, with more than 4 inches estimated in Joliet, 3.6 inches in Chicago and 3.5 inches in Homer Glen. Some of those totals were expected to be gradually wiped out by Tuesday morning rain, however.
And though suburbs to the north and west didn't see much snow overnight, some could still see as much as 9 inches by Tuesday evening, the NBC 5 Storm Team said.
According to the National Weather Service, a winter storm warning remained in place until midnight for Lake, McHenry, DeKalb, Kane and LaSalle counties in Illinois and until 3 a.m. Wednesday in Kenosha County in Wisconsin. The warning in Illinois, however, was extended until 4 a.m. Wednesday on Tuesday afternoon, warning of an additional 2-5 inches of snow.
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Several other counties in Illinois, are under a winter weather advisory through the overnight hours.
According to NBC 5 Storm Team Meteorologist Alicia Roman, widespread snow is expected to continue falling throughout the day, with most areas seeing heavy snow through 9 p.m., and tapering overnight.
Wind gusts early Tuesday clocked in at 20-25 miles per hour, Roman said, with gusts expected to reach as high as 40 mph by afternoon.
Additionally, snowfall rates were expected to exceed one inch per hour, creating dangerous driving conditions for both the morning and evening commutes.
"Heavy, wet snow and dangerous travel conditions expected," the NWS warned in an alert. "Travel could be very difficult. Patchy blowing snow could significantly reduce visibility."
Further south, a rain and a snow mix was expected to gradually change back to all snow by the evening.
By Tuesday evening, counties in the advisory may only see an additional inch of snow accumulating.
ComEd officials on Monday announced the company’s Emergency Operations Center will open Tuesday to assist with any problems that may arise.
“The kind of snow forecasted this week can be especially problematic because it can cause branches and entire trees to topple onto our power lines,” COO Dave Perez said in a statement.
The state of Illinois issued an alert to drivers on Monday, advising of slick conditions along with reduced visibility and urged residents to avoid traveling if possible.
"If you must travel, be advised your destination could have significantly higher amounts of snow than where your trip originated," the alert said. "Slow down, anticipate much longer travel times, increase braking distances and expect conditions to deteriorate."
The Chicago Office of Emergency Management and Communications issued a similar alert Monday, warning drivers to "plan on slippery road conditions."
According to Chicago officials, more than 200 plows were expected to be deployed across Chicago ahead of the storm.
MORE: Here's how to check road conditions in Illinois as snow arrives
As of Tuesday morning, the snowstorm had already begun to snarl air travel, with more than 100 flights at O'Hare and Midway International Airports canceled.
MORE: Chicago residents warned against using excess salt amid snowfall
Additional rounds of snow are possible throughout the week, with a quick-moving system Thursday morning. Friday, another winter storm could "pack another punch," Roman said, bringing several more inches of "shoveable snow."
By next week, temperatures are expected to drop into the teens.
