Polar vortex to end warmer than usual winter

MONTREAL – This year has been a fairly easy year so far in the weather department. It has been warmer than average across most of the country since the beginning of winter, but as we all suspect in the back of our minds it can’t last forever and it is looking like it won’t.

Enter the Polar Vortex.

That’s right. It is set to return to parts of Canada at the end of January and bring some big changes, especially to the west and the prairies.

The map below shows just how warm it has been compared to average temperatures since January first. The orange, red, brown and even white areas show just how warm it has been and how large of an area that warmth spans.

In Montreal, the average temperature for December in 2020 was -2.1 degrees Celsius, which is 3.3 degrees warmer than average for December.

So far in January the average temperature has been -4 degrees Celsius, which is 5.7 degrees warmer than the monthly average.

The Polar Vortex typically resides over the poles, but because of stratospheric warming, a period that we have been going through lately, this has relaxed the typically tight upper air circulation that keeps it in place.

Meaning the Polar Vortex is coming for us.

When that circulation around it eases off, we start to see chunks of that bitterly cold air sinking further south, and North America is a prime candidate to receive that air.

This is also supported and aided by the pattern starting to shift into a more classic La Nina, which has been developing in the equatorial waters of the Pacific Ocean. This means the jet stream is going to move south in the west, allowing cold arctic to spill down, even to the coast.

This will also bring a more active pattern to the Great Lakes and southern Quebec and open up the door for some decent lake effect snow on the relatively ice free Great Lakes.

Another chance will be in place for the cold air to slide to the east of the Ottawa River and deliver the cold into Montreal.

Does this mean the rest of winter is going to be miserable? No.

Will it be record cold? Not even.

Will it last all of February? Not likely either.

So what then?

We are just going to be get a taste of good ol’ fashioned winter weather that we are used to seeing for a few weeks out of the season. Let this serve as that heads up: winter is coming.