The Chicago National Weather Service Forecast Office has issued a Winter Weather Advisory effective from 6PM CST Friday until noon CST Saturday for in general the Chicago area and northwest Indiana along and south of Interstate-80.
The following northeastern Illinois and northwestern Indiana counties are included in the Advisory: In northeast Illinois…LaSalle, Grundy, Will, Kankakee, Livingston, Iroquois, and Ford…In Indiana..Lake, Porter, Newton, Jasper, and Benton. This will include the following cities…Ottawa, Morris, Joliet, Kankakee, Pontiac, Rensselaer, Watseka, Paxton, Gary, Valparaiso, Morocco, and Fowler.
Snow is forecast to spread north and east over the area early Friday evening and persist through the night into Saturday morning with total accumulations of 3 to 6-inches. Snowfall rates could be up to one-half inch per hour reducing visibilities with roads becoming snow covered – making for dangerous travel conditions. The snow should spread north over the remainder of the Chicago area during this same timeframe with a gradient of lesser snowfall north to the Illinois-Wisconsin border.
Note that the southern portion of the Chicago area under the Winter Weather Advisory is but a small portion of a much larger Winter Weather Advisory area (shaded in purple on map below) that includes all or a portion of Illinois south of Interstate-80, Indiana, western Ohio, extreme southern Lower Michigan, and southern Missouri.