As mostly calm and quiet early December weather spans the Prairies this week, a blast of frigid arctic air will plunge south later in the weekend. This is expected to be some of the coldest air of the season so far for the central and eastern Prairies, with daytime highs near or even below -20°C by next Monday.
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TIMING THE BLAST OF ARCTIC AIR
Just as things were feeling rather comfortable for December, a change in the current pattern will send temperatures tumbling, and quick.
Cold air streaming across the pole from Siberia -- cross-polar flow -- will be moving into the Prairies by the weekend, and that will send temperatures several degrees below seasonal.
"Temperatures will feel like some of the coldest January days that we get, especially across parts of Saskatchewan and Manitoba," says Weather Network meteorologist Jaclyn Whittal.
Though the coldest air will funnel in farther east, when you count the wind chill it could still feel closer to -20 for central Alberta by early next week, too.
A swath of light snow is also expected on Saturday with a clipper system moving through ahead of the arctic air. Upslope flow will bring several centimetres of snow to southern Alberta -- including the city of Calgary -- on Saturday night as the arctic air surges further to the south. Around 5 cm of snow is possible from Edmonton to Red Deer, while parts of the Elbow region could see as much as 20 cm.
Temperatures next week will be the coldest air of the season so far across the eastern Prairies as daytime highs hover around -20°C, with dangerous wind chills into the -30s.
"Only fairly light winds are expected, which is a good thing because wind chills into the -30's for several days could have been much worse with stronger winds," Whittal says. "This air mass will also be on the move as it pushes east into Ontario by the end of next week."