A winter storm watch has been issued for north Niagara including St. Catharines and Grimsby.
Environment Canada expects a winter storm to hit the area late Friday afternoon.
Officials say the snow could become heavy at times and combined with blustery winds create dangerous driving conditions.
Total accumulation could be between 10 to 20 cm.
Temperatures in some areas may stay above zero during the snowfall, if so that may limit the accumulation.
At this point there is some uncertainty where the heaviest snow will hit.
Winter storm warnings or snowfall warnings may be issued as the system approaches.