The National Weather Service has expanded an existing winter weather advisory for all of northern Illinois and northwest Indiana, with snow expected to snarl traffic during the morning commute in most locations.
According to the latest guidance, the advisory will take effect at various times throughout the area, with anywhere from 1-to-6 inches of snow possible by Wednesday evening, with parts of central Illinois and central Indiana seeing the heaviest accumulations.
The new advisory will take effect at midnight in LaSalle, Kendall, Grundy, southern Cook, Will and Kankakee counties in Illinois, as well as Lake, Porter, Newton and Jasper counties in Indiana.
The Illinois counties will remain under that advisory until 6 pm, as will Newton and Jasper counties, according to the alert. Areas closer to Lake Michigan, including Lake and Porter counties in Indiana, will remain under the advisory until midnight Thursday.
While exact snowfall predictions are still being dialed in, the National Weather Service says that the highest accumulations will likely occur in central Illinois and in Indiana, with Lake, Porter, Newton and Jasper counties potentially seeing 3-to-6 inches of snow, with some locally-higher totals possible.
In Illinois, areas south of Interstate 80 could see between 2-to-4 inches of accumulation, with the morning commute being largely impacted by the snowfall.
Lake and DuPage counties, as well as north and central Cook County, will go under the advisory at 3 am and will remain under the advisory until 9 pm
Those areas closer to the lake could see slightly larger accumulations, with 2-to-4 inches of snow possible.
Finally, McHenry, DeKalb and Kane counties will be under an advisory from 3 am to 3 pm Those counties should see less-intense accumulations, but road conditions Wednesday morning could still be hazardous.
The Wednesday snowfall is the first of several disturbances that could bring wintry weather to the area, with another clipper system expected to arrive Friday and several more rounds of snow possible on Saturday and into Sunday, according to the NBC 5 Storm Team.