Environment Canada has issued a winter storm watch for Windsor-Essex and Chatham-Kent.
The national weather agency says 20 to 30 cm of snow, or nearly 12 inches, is expected to fall between Wednesday and Friday morning.
The storm will begin with rain on Tuesday night and then transition to snow by early Wednesday morning.
Wind gusts could reach up to 70 km/h which could reduce visability with blowing snow.
Travel is expected to be hazardous.