https://forecast.weather.gov/product.php?site=LOT&issuedby=LOT&product=AFD&format=CI&version=1&glossary=1

“By the time the lake effect ends on Monday, total snow amounts will vary considerably across short distances. Where the snow bands are most intense, total snow accumulations of 12 to 18 inches are expected with a ceiling of 2 to 4 feet if snow bands end up stationary.

This threat appears to be most pronounced over Cook county, but may extend to Lake County Illinois and Lake County Indiana, as well. Outside of Cook County, the highest snow totals are expected east of I-355 in the Chicago area, east of I-57 south of the Chicago area, and north of the Kankakee River Valley in northwestern Indiana.”