Canada braces for a polar vortex as winter weather intensifies

Your Morning meteorologist Kelsey McEwen has an update on heavy snow and winds in the Prairies, and a drop in temperatures in northern Ontario.

The arctic cold air, due to a “disrupted” polar vortex, is making an unwelcome return to some parts of Canada, bringing frigid temperatures and severe weather alerts across the country.

The low-pressure system will bring minus-double-digit temperatures across the Prairies on the weekend, according to CTV Your Morning’s meteorologist Kelsey McEwen.

Major urban cities like Toronto, Ottawa and Montreal are gearing up for a significant temperature drop by Friday as well, McEwen said.

What is a polar vortex?

A polar vortex is a large area of low pressure and cold air surrounding each of the Earth’s poles, according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

Typically, during the northern hemisphere’s winter, the polar vortex will expand, sending cold air southward and often resulting in outbreaks of Arctic air across Canada and into the United States.

The NOAA notes that it’s the current of winds at the edge of the polar vortex, known as the polar jet stream, that plays a big role in our day-to-day winter weather in the mid-latitudes, not the vortex itself.

When the polar vortex picks up in strength, the polar jet stream stays further north, and at the surface, this “stable stratospheric state” is linked to an even colder than usual arctic. When that stable state is disrupted, and the cold air spreads south, much more of the country is impacted.

Here are the weather conditions across Canada:

A mixed bag for the Prairies

An Alberta Clipper – a fast-moving low-pressure system – is plaguing north of the Yellowhead, where snow squall warnings are in effect. According to Environment Canada, intense snowfall and gusty winds up to 80 km/h are forecast. Visibility may be reduced to near-zero.

All over Alberta, a mixture of wind, freezing rain and snowfall are expected with up to 25 centimetres of snow expected in Edmonton from Thursday afternoon into Friday. Snow will taper off Friday overnight.

Strong northwest winds with gusts of up to 90 km/h are expected in northern Alberta, with winds due to weaken by the Thursday evening.

In Manitoba, communities like Berens River, Cross Lake, Island Lake and others are in for snowfall of up to 20 centimetres, possibly reaching 25 centimetres by Friday.

Residents in Winnipeg are poised to brave the Alberta clipper including those in Red River Valley on Friday morning with snowfall and blowing snow.

The weather system will move through central Manitoba Thursday night, bringing heavy snow to northern regions.

Environment Canada said southern Manitoba has seen milder temperatures, but the cold frontal passage of this clipper will see temperatures drop quickly, with wind gusts of 90 km/h.

Areas in Saskatchewan are also in for snow of up to 25 centimetres, before tapering off Friday morning. A blowing snow advisory is also issued, warning of poor visibility. Above-zero temperatures may delay the onset of blowing snow until later Thursday evening or night, the weather agency said.

Ontario faces snow advisories

Ontario is also under weather advisories with snowfall rates of two to four centimetres per hour from Thursday morning through late afternoon and totals ranging from five to 10 centimetres.

In areas like Ear Falls, Red Lake and Pikangikum, snowfall will be heavier, with total accumulations of 15 to 20 centimetres starting Thursday night through early Friday afternoon.

Wintry weather for northern Canada

In Nunavut, Baker Lake is under a blizzard warning forecast to start Thursday evening. Strong north winds of 50 to 70 km/h will bring near-zero visibility in blowing snow.

The strong winds and dropping temperature will cause very cold wind chill values between -50 and -55 Thursday night and Friday.

In Yukon, Cassiar Mountains and Watson Lake residents will experience between 20 to 25 centimetres starting Thursday morning.

With files from CTVNewsToronto.ca