Dangerous winter conditions are expected in the Chicago area this week, but the timing for when they could start has already shifted.
According to recent forecasts, it appears the timing of the storm has shifted earlier, with a winter storm watch now taking effect in some counties Thursday morning.
The watch was originally not expected to begin until Thursday evening, but the National Weather Service changed that designation Tuesday morning.
The winter storm watch was moved up for some counties to as early as Thursday morning, including in McHenry, DeKalb, Kane, LaSalle, Kendall and Grundy.
Things will "rapidly" worsen heading into Thursday afternoon, with snow growing more widespread and becoming stronger.
A winter storm watch for Lake, DuPage, Kankakee, Cook and Will counties in Illinois, and Lake, Porter, Newton and Jasper counties in northwest Indiana, was also moved up, now beginning Thursday afternoon, according to the National Weather Service.
According to forecasters, the timing of the intensity was originally later, but new models show "slightly faster arrival of deteriorating conditions Thursday afternoon."
The alert warns that "falling and blowing snow may result in white out conditions with zero visibility at times, making travel extremely difficult, if not impossible."