Blasts of frigid Arctic air could send temperatures tumbling in December and herald the arrival of a more “traditional Canadian winter,” a meteorologist for the Weather Network predicts as it releases its seasonal outlook.
Most of Canada is expected to see near or colder than normal temperatures, and near or above normal precipitation and snow, says the network’s seasonal forecast for December, January and February.
There’s still some uncertainty about whether the second half of winter’s fury will be widespread or more focused on Western Canada, said meteorologist Doug Gillham.
The country experienced its warmest winter on record two years ago ahead of last year’s more typical season, Gillham said. This year is expected to look more like last year, “but the signals for cold are actually a little bit stronger,” Gillham said.
One of those signals is the polar vortex, strong winds circling up to 50 kilometres above the Arctic that keep frigid air locked near the poles. A period of surging temperatures up in that part of the atmosphere is expected to disrupt the vortex and spill that cold out over Canada in December and January.
A second consecutive winter with a weak La Nina is also set to have a cooling influence, Gillham said. The climate pattern, tied to shifting patches of water in the Pacific Ocean, can often lead to colder and stormier conditions across much of Canada.
Put those two things together, the disrupted polar vortex and the weak La Nina, and the potential goes up for extended stretches of extreme temperatures, he said.
“So, if you enjoy winter activities, that’s good news. If you think, ‘I don’t need snow tires anymore,’ well, you may want to rethink that,” Gillham said.
What counts as a typical or normal Canadian winter has changed over recent decades. While they fluctuate, average winter temperatures are about 3.7 degrees warmer now than in the mid-20th century as climate change, driven by the burning of fossil fuels, reshapes Canada’s winter way of life.
Yet the baseline used to figure out what’s “normal” for the forecast is a more recent period, between 1991 and 2020.
Alberta is expected to see colder than normal temperatures dominate this season, though the pattern will relax at times, Gillham said. Snowfall totals could be higher in the southern and central Rockies and through Calgary, with near-normal totals for the rest of the province, including Edmonton through Fort McMurray.
The forecast’s strongest signals for cold show up in Manitoba and Saskatchewan.
There are signs the cold there could linger well into March. Some will be longing for spring warmth by then, but a delayed spring start can bring some benefits to the Prairies, Gillham noted. A cooler spring can maintain the snowpack, keeping up soil moisture and helping cut into early-season wildfire risks until rainier days arrive.
For the territories, near-normal temperatures are expected across Yukon and the Northwest Territories, and into southern parts of Nunavut. The rest of Nunavut is expected to see above normal temperatures, partly because of the disrupted polar vortex, Gillham said.
It’s a good forecast for ski lovers in the Rockies, southern Ontario and southern Quebec, with resorts in those areas set to be well-covered for the holidays, Gillham said.
As for a white Christmas, it’s still a bit early to make that prediction, Gillham said.
“But when we step back — the high level, the country as a whole — I think more of Canada will see a white Christmas than we often do,” he said.
“That doesn’t guarantee that your backyard will be white, but with the strong start to the season, we think more of the country, but not everyone, will see a white Christmas.”
This report by the Canadian Press
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