A WINTER WEATHER ADVISORY has been issued for all of northern Illinois and southern Wisconsin beginning Tuesday at 9pm and lasting through Wednesday afternoon and evening (depending on location). The advisory issued not because of the snow we are expecting Tuesday night, but because of the impacts of blowing and drifting snow from the increasing wind.
Southerly winds have been blustery for much of Tuesday afternoon. And while that helped bring temperatures into the low 30s, wind chills remained in the upper teens and low 20s. Blowing and drifting snow has been reported on east/west roads throughout the afternoon, worsening as the sun has set and wind speeds have increased. There has even been some drifting reported on north/south roads.
South winds will gust to around 30 mph through Midnight, or a little after, until a cold front comes through. Temperatures will remain in the low 30s during that time, but then quickly tumble once the front passes. This will pull temperatures quickly down into the teens by sunrise Wednesday, with temperatures actually falling into the afternoon. Wind speeds will increase even further once the front passes, gusting close to 40-45 mph Wednesday morning and early afternoon. Deteriorating road conditions, first on east/west roads tonight and then north/south roads Wednesday, will cause hazardous and slick travel through the morning commute, especially in open and rural areas. Near white-out conditions may also occur in opens areas through the day. Be prepared for rapidly changing weather and road conditions!
Wind chills will also drop, remaining below zero through Wednesday afternoon, Thursday afternoon and Friday afternoon. While the wind is expected to lighten up Thursday and Friday, wind chills Thursday morning could reach near -20 degrees, and then -25 degrees Friday morning. Frostbite with those wind chill temperatures can occur within 20-30 minutes.