To pull off this incredibly rare and complex feat, myriad different parts of the atmosphere work together in tandem, dipping every square centimetre of Canada below the freezing mark.
Trust me, it's tough to get all 10 million square kilometres of Canada below freezing at the same time.
For every provincial capital to remain below the freezing mark, particularly Victoria, everything has to come together to hold the frigid air coast-to-coast. Victoria has only spent 28 days below the freezing mark for an entire day this century, and strong winds flowing from the continental high-pressure inland will make this a reality.
First, a ridge has to set up near Alaska, to buffer the normally active Pacific jet and allow cold air to stream south. A disruption of the polar vortex several weeks ago allowed decaying lobes of Siberian air to flush south.
Finally, a strong blocking ridge in Northern Canada is the final piece of the puzzle - consider this the key. It locks and shunts the cold air south, trapping it in place, with no escape route in sight.
Oh, and Florida has to be warm. A strong southeastern ridge helps limit the final escape route for the cold.
There have only been two periods this century where Canada's capitals all together spent two days below the freezing mark. December 19 and 20, 2008, and February 5 and 6, 2014.
Oh, December 2008, where up to one metre of snow fell across parts of the South Coast of British Columbia.
February 2014 had extremely impressive monthly anomalies in the Prairies, up to 17°C below normal -- that’s particularly anomalous for an entire month.
This week, the widespread Canadian chill will be the latest on record since at least the beginning of the 21st century.
2021 threatens to do the unheard of -- three consecutive days with at or below zero temperatures across all of Canada, with Thursday already in the rearview mirror and two more coming up.
Arctic air is set to stick around, promising an active storm track in Eastern Canada, but with temperatures slowly emerging from the proverbial freezer in Western Canada over the next couple of weeks.