Parts of southern Ontario could see 10 cm of snowfall by late Wednesday morning, according to Environment Canada.
The agency says a band of heavy snow will leave a small section of the province with between 5 and 10 cm of snow before it moves out.
Affected areas include Goderich, London and St. Thomas in the west, as well as southern parts of Perth County, and all of Oxford and Norfolk counties.
Poor visibility is also a concern as the snow moves through.
Forecasts for Waterloo-Wellington call for about 2 cm of snowfall in the morning, with a 60 per cent chance of showers or flurries through the afternoon and more flurries likely overnight.
