CHICAGO – A Wind Chill Advisory (light-blue-shaded area on the highlighted warning map above) has been issued, calling for wind chills as low as -20-degrees are forecast to occur later tonight into Sunday over the northern and western portions of the Chicago area including Winnebago, Boone, McHenry, Lake, Ogle, Lee, DeKalb, and Kane Counties. The remainder of the Chicago area could experience wind chills as low as -5 to -15-degrees during the same time period.
A Winter Weather Advisory (dark blue-shaded area on map above) for heavy lake-effect snow is in effect for the western portion of Lower Michigan into extreme north-central Indiana Sunday into Monday with as much as 6 to 10-inches of snow possibly accumulating.
Wind Chill Advisories (light-blue-shaded areas) are also in effect for most of Wisconsin and eastern Iowa into western Illinois for wind chills -25 to -35-degrees later tonight into Sunday. Note Wind Chill Warnings (gray-shaded areas on the map above) are in effect for wind chills -35 to -45-degrees tonight and Sunday across a good portion of Minnesota into northern Iowa and the eastern half of the Dakotas.
The leading edge of a very cold High pressure air mass originating in northern Canada is nosing into the northern plains and Midwest, reaching into the Great Lakes, central plains, and Ohio Valley this weekend.
As the Chicago area becomes engulfed in this approaching cold air mass, temperatures will fall out of the 20s through the teens into single digits tonight and hold through Sunday into Monday. Sub-zero eadings will probably occur in northern and western sections tonight and be widespread acosss the entire Chicago area Sunday night into Monday moring. Northwest winds will strengthen gusting over 20 miles per hour – not only combing to produce the dangerous wind chills, but also heavy lake-effect snow along and inland of the eastern Lake Michigan shoreline.