Environment Canada has upped the snowfall ante Sunday morning with a prediction of as much as 20 cm overnight. The snow will become heavy at times Sunday evening, enhanced by a heavy snow band off of Lake Ontario. Visibility is expected to be limited making travel challenging. Snowfall totals of 15 to 20 centimetres are expected by the time it tapers off overnight. Cold brisk winds on Christmas Day will likely create some local blowing snow as well. Travelers are encouraged to adjust their plans if possible.