The Toronto forecast only had one night of cold, and now it is extended.
This is a common pattern, with the tropical plumes hitting high.
The wind is coming down from the Yukon and dragging the cold along. My blob hypothesis only involved -50 air which may have unusual properties. Mainly that it become more resistant to convection, and being shifted by the wind. That was demonstrated by the tropical winds 'bouncing off' that type of air mass. Anyway, we have cold for now.
The general forecast is for a warm March. I doubt it.