Despite the sunshine Monday afternoon temperatures did not warm much above 40 degrees. Mostly clear skies will take us through most of the evening before cloud cover increases after Midnight. The increase in cloud cover is a result of a strong, fast moving clipper system currently moving out of southern Canada. This low will dip southeast through the Plains and Midwest, reaching the Stateline by Tuesday afternoon.
Moisture moving in ahead of the low will allow a band of snow to develop after roughly 3am Tuesday, spreading from west to east through sunrise. The window of snowfall during the morning will only last for about an hour or two but could cause some impacts for the early morning commute. Any accumulations are likely to remain on grassy and elevated surfaces, such as bridges and overpasses, and with temperatures at or below freezing during that time this could cause some slick conditions for early commuters.
Following the first round of snow in the morning we will see a break mid-morning ahead of the main low-pressure system. This will settle in over southern Wisconsin and northern Illinois during the late morning and afternoon. As it does, scattered wind-driven snow showers will occur throughout the afternoon. Temperatures warming above freezing should limit any potential accumulation on the roads but with the wind and heavier bursts of snowfall, visibility will drop as a result making it difficult to drive.
Most of the snow will be wrapping up between 4pm-5pm, but blustery northwest winds will continue around 35 mph. With temperatures only warming into the upper 30s wind chills throughout the day will remain in the middle 20s. Those numbers will drop through the evening down into the low 20s after sunset. Make sure you dress appropriately as it will be quite cold during day.
As for snow accumulations, most will remain under an inch. So, while we’re not expecting a big snow event for Tuesday, the impacts will definitely be there – especially with it being the first snow of the season. Take it slow, remember winter driving skills, and make sure to dress appropriately.