Update: Winter Weather Advisory for a wintry mix of Freezing Rain/Drizzle and accumulating snow Monday from late afternoon/evening into Tuesday, generally in counties along and north of Interstate-80
A Winter Weather Advisory is in effect for a good portion of the Chicago area along and north of Interstate-80 (purple-shaded counties on the headlined map), calling for a freezing rain/drizzle/wet snow mix beginning near Interstate-80 late afternoon/early this Monday evening, spreading north and east. Snow is likely farther north along the Illinois-Wisconsin state line tonight. Precipitation is expected to change over to all snow Tuesday, ending from the west by evening. Dangerous travel conditions will exist with slick and eventually snow-covered roads/highways.
With cold air in place over the Chicago area, low pressure will move northeast out of Kansas, tracking over Chicago early Tuesday. A broad area of cloudiness and light freezing rain or drizzle should develop over our area out ahead of the approaching weather system from south to north and east, with the greatest threat of a prolonged period of frozen precipitation and wet snow along and north of Interstate-80 Monday night into Tuesday. As the low pressure moves away to the east Tuesday, west-northwest winds will strengthen gusting over 35 mph, pulling much colder air into northern Illinois, with a wet snow gradually ending from west to east later Tuesday afternoon/evening.