A yellow now squall watch is out for parts of Lambton County.
Environment Canada says total snowfall accumulations of 20 to 40 cm are expected and that higher amounts are possible in some spots.
Near-zero visibility is expected in some areas with heavy and blowing snow.
The watch is out for early Sunday morning and is expected to end Sunday afternoon or evening.
Travelling could be dangerous, and road closures are possible.
The national weather agency also said that as winds become northerly early Sunday, a particularly strong snow squall is expected to develop off Lake Huron. The heaviest snowfall is expected west of London. However, snow squalls may move into western portions of the city at times.
