Polar vortex to bring record cold temperatures to Ontario: Environment Canada

People walking along the Rideau Canal Western Pathway in the midst of the COVID-19 pandemic, in Ottawa on Sunday, May 3, 2020. THE CANADIAN PRESS/Justin Tang

TORONTO — Despite warm weather last weekend, a cold snap is moving into Ontario

Environment Canada warns that a polar vortex is headed for much of Ontario and is expected to bring record cold temperatures to the province for at least the next week.

Gerald Cheng, a warning preparedness meteorologist with Environment Canada, said a polar vortex has been sitting over the North Pole for much of winter and has helped contain the Arctic air to keep conditions relatively mild across Canada.

Now, that vortex is starting to break down and a large chunk will fall onto eastern Canada.

"Usually this cold wind remains in the pole, for us that’s the North Pole, but it is being pushed down right now into Ontario," Cheng said in a telephone interview with CTVNews.ca on Tuesday. "When that northern air comes south, that’s when we feel that really cold weather."

Cheng said residents in some areas of eastern and southern Ontario can expect to see nighttime temperatures dip below zero on Friday and Saturday, with cooler temperatures sticking around until the long weekend. Some areas may also see snow flurries and squalls.

Cheng said the seasonal daytime temperature for Ontario during this time of year is usually around 17 C with nighttime lows not going below 7 C.

"So we're talking about nine to 10 degrees off, so you can expect record cold temperatures for the time of year," Cheng said. He added that despite recent spring weather, Ontarians should remember that winter didn't end that long ago.

"Spring is considered a transition season because it's really the point between the extremes of winter and summer. Winter is supposed to be cold and summer is supposed to be hot. So in spring, we still have these different air masses fighting it out over eastern Canada, and that is why we sometimes get these big swings in temperatures," Cheng said.

Cheng said residents will feel the effects of the polar vortex into this weekend and throughout next week. He said temperatures will gradually increase towards seasonal come the end of May, but there is a threat of winter precipitation until then.