It might have been warm this past weekend, but it looks like an unusual blast of mid-spring winter weather could be headed for southern Ontario.
Today (May 4,) The Weather Network warned that a polar vortex–yes, a polar vortex in May–could be on route.
“There is high confidence that Ontario will see temperatures well below seasonal since some of the most extreme temperature anomalies on Earth will soon move into this region,” Tyler Hamilton, Meteorologist, writes in the report.
“Hot on the heels of our first 20 [degree day] of the season for many communities across Canada, the chilliest air relative to normal around the globe is set to swirl across Ontario by Friday.”
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In Brampton and Mississauga, temperatures are expected to drop to just 4 degrees on Saturday, with a mix of rain and snow in the forecast. According to the forecast, it will feel more like -1.
In Halton and Hamilton, temperatures will hit 5 degrees on Saturday (but it’ll feel more like 0 degrees outside). A mix of rain and snow is expected.
The Weather Network says temperatures could dip to 20 degrees below seasonal by the end of the week.
In the report, Hamilton said the core of the polar vortex (tropopause) is currently streaking across Nunavut.
“Much of the winter pattern in 2020 featured an intense polar vortex at high latitudes, even causing a temporary depletion of ozone, but it’s a bit of a paradox – it remained unperturbed while most of North America basked in relatively warm temperatures,” he said.
“More recently, the atmosphere has featured much more mid-latitude blocking, which are the weather patterns that disrupt the typical westerly flow. The mid-latitude blocking will be the trigger that will send this extreme temperature anomaly on a collision course with Ontario.”
While snow isn’t unheard of in May, Hamilton says it’s quite rare for southern Ontario.
According to Hamilton, this year’s snowfall threat will ramp up by Thursday for northern Ontario and by Friday for southern Ontario.
“This pattern is incredibly dynamic and bears watching over the next several days, but safe to say some hard freezes are guaranteed, and lingering threats of wintry precipitation are begrudgingly on the table,” he said.