Ontario, Quebec may see winter storms later this week: Environment Canada

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Canadians across several provinces are bracing for a fast-shifting stretch of winter weather this week, as a series of systems sweep across regions.

The upcoming winter patterns may also signal the start of a much colder phase of winter driven by changes high in the atmosphere, CTV’s Your Morning meteorologist Kelsey McEwen said in an interview.

Here’s a look at the weather for this week.

Snow in the Prairies

A fast-moving system will deliver a burst of winter to parts of Alberta and Saskatchewan on Monday, bringing in heavy snow and reduced visibility.

McEwen said areas around the Cypress Hills – stretching from southeast Alberta into southwest Saskatchewan – will see up to 20 centimetres of snow, while other areas in the provinces will see between 10 and 15 centimetres.

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Blowing snow from strong, northwest winds will put visibility at less than 500 metres at some points.

According to McEwen and Environment Canada, it’s going to be a brief weather event and will taper off towards the evening. As the snow reduces, the “gusty” winds will develop, and temperatures will drop.

“Prepare for quickly changing and deteriorating travel conditions,” Environment Canada warned.

Winter storm brewing in Ontario, Quebec

A much more powerful system is taking shape and is set to impact Ontario and Quebec through the week.

McEwen said it will start in northeastern Ontario, with rain beginning Tuesday and changing to snow, west to east by Tuesday night.

Communities around Lake Superior could see up to 35 centimetres of snow, along with reduced visibility by the time the system pulls away on Friday.

Strong northerly winds will accompany the snow, McEwen said. This has prompted a winter storm watch in Ontario, issued by Environment Canada, rather than the standard snowfall warning.

Further south, cities including Toronto, Windsor and Ottawa will begin the week with rain and easterly winds.

McEwen said sometime overnight Wednesday to Thursday, colder air will move in across all regions, with snow expected in southern Ontario.

“This isn’t just going to be northern Ontario, this will be a province-wide Ontario-Quebec event,” McEwen said.

Temperatures will be location dependent, McEwen explained. In Timmins, Ont., conditions will hover near freezing early in the week but by Friday, the daytime high will plunge to -8 C with Saturday potentially as cold as -10 C.

Toronto could reach 11 C on Wednesday but by Thursday, daytime temperatures will fall to 1 C triggering the rain-to-snow transition.

“Avoid non-essential travel and outdoor activities. Be very careful if walking or driving,” the weather agency warned. “Prepare for disruptions to transportation, services and utilities.”

Meanwhile, parts of Quebec are under a special weather advisory, warning residents of snow accumulating up to two centimetres per hour, with “significant” snowfall expected mid-week between Wednesday afternoon to Thursday evening.

Cold air

McEwen said the cold snap arriving this week may only be the beginning.

A strengthening upper trough over Canada is pushing the jet stream southward, allowing arctic air to spill across the country.

McEwen said we are seeing signs of a “stratospheric warming event,” a high-altitude phenomenon that allows colder air to “flood in.”

The pattern is reminiscent of the 2014 polar vortex event, according to McEwen, with cold temperatures like that into next week.

“What we are getting this week is a preview of what we could see more of throughout this winter as colder air has a better availability of moving across Canada through this winter,” she added.