Toronto is enjoying a somewhat mild end to October, but something strange is happening high above the Arctic, and it could switch up Canada’s winter weather forecast.
According to The Weather Network, the polar vortex is showing signs of weakening much earlier than expected, with forecast models suggesting a historic disruption in early November, just as the system should be gaining strength ahead of winter.
When this happens, it can allow frigid Arctic air to move farther south, potentially bringing colder temperatures to Toronto. So, maybe bad news for Torontonians hoping to avoid an early deep freeze, but it all depends on how the jet stream responds and where the coldest air eventually travels (in some cases, Europe or Asia could experience the effects instead).
There’s also another twist to look out for: Canada is heading into winter under the influence of a very strong El Niño, meaning Toronto (and the rest of the country) could experience a warmer-than-normal winter, although it doesn’t rule out significant snowfall or occasional blasts of Arctic air.
The Weather Network says its outlook for a generally mild start to winter hasn’t changed despite the latest polar vortex developments (because the Arctic hasn’t had as much time to build up an intense reservoir of cold air, a disruption in November may also be less harsh than one occurring in January or February).
For now, meteorologists will be watching how the polar vortex develops throughout November and whether the disruption eventually affects weather patterns farther south.
As for the rest of the winter: Environment and Climate Change Canada’s latest seasonal outlook favours above-normal temperatures for Toronto: from December through February, the forecast gives Toronto a 50 to 59 per cent probability of above-normal temperatures, while from January through March, Toronto has a 70 to 79 per cent probability of temperatures running above normal.