Early predictions of a strong pre-holiday ski and snowboard season are fast going off the rails as we move through December, thanks in large part to atypically warm Great Lakes temperatures and a persistent stream of mild Pacific air.
It feels like anything but a “typical Canadian winter” right now in Toronto, where sunny skies, rising temperatures and melting snow are giving off distinct springtime vibes.
By Thursday, locals might be wondering whether winter has come and gone already as temperatures reach 16 C.
That’s right — forecasters are calling for a high of 16 C on December 16. Like… what?
“During mid-November, the jet stream pattern actually changed as we expected it to. However, the impact on the weather down here on the ground where we all live was much less than expected,” explains Weather Network meteorologist Dr. Doug Gillham of the wonky temperatures.
“The colder jet stream pattern failed to deliver any noteworthy cold air because temperatures across northern Canada were exceptionally warm at the time. So, when cold fronts came through and ushered in air from the north, the best that they could do was to knock our temperatures back down to normal.”
Some cold Arctic air did finally start coming down from the north into Southern Ontario late last month, but it was tempered by the feverish Great Lakes, lending the region a few major snow events but never a sustained period of cold weather.
“The key reason for this unexpected development has been the exceptionally powerful jet stream over the Pacific Ocean, which has been pummelling the B.C. coast with a parade of storms and forcing mild Pacific air to spread east across the U.S. and southern Canada,” says Gillham. “So, each time Arctic air has reached our region, it has been quickly swept away by milder Pacific air.”
As for the warmer-than-normal ten days ahead, we can blame that on balmy temperatures in The States.
“Temperatures have been well above seasonal just south of the border, especially across the western and central U.S.,” reads Gillham’s Weather Network forecast. “That mild air surged north into Ontario and Quebec, and that will bring an extended stretch of above-normal temperatures.”
Enjoy it while you can, if you’re not a fan of freezing cold winters, because frigid conditions could still very much be headed our way.
“As we look at how the weather pattern is evolving around the globe, there are actually a number of things happening that are typically precursors to a major pattern change which would result in a more consistent flow of Arctic air rather than Pacific air into Ontario and Quebec,” says Gillham.
“If the pattern develops as expected, that will set the stage for a few weeks of very wintry weather (cold and snowy) between Christmas and New Year’s and continuing well into early January.”