Arctic Blast Grips the Great White North as United States Experiences Most Unseasonably Mild Christmas in History.
A prolonged deep freeze has enveloped a bitter and extended period of frigid weather, with thermometers lingering in the minus 20 to minus 40 Celsius range for weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading in half a century.
Prolonged Freeze of Extreme Cold
Meanwhile, Mayo and Dawson endured sixteen nights in a row below -40C, with Mayo plunging to -50.4C earlier this week. The capital, Whitehorse, likewise saw 10 nights when the cold dipped under -30 Celsius.
This Arctic air mass pushed further southward through Christmas week. Christmas night saw Edmonton's temperatures plummet below minus 28C.
December 26th was anticipated to usher in readings no higher than -20 Celsius in numerous areas, including Edmonton, Montreal, Ottawa and Quebec.
Expected to Continue into the New Year
This harsh winter weather is expected to continue into the new year. Authorities have cautioned about potential power failures in the Yukon soon, as the territory’s power grid comes under strain from peak power usage levels.
The lengthy cold snap originates from the Arctic vortex settling across the northern part of the continent this month, enabling a surge of icy Arctic winds to descend. Next week, the cold air mass is expected to retreat north allowing more temperate air from the Pacific to sweep across the United States and penetrate southern Canadian regions.
Stark Contrast with US Warmth
In stark contrast, parts of the US experienced their warmest Christmas Day on record as temperatures soared about 15-30C above the seasonal average. For numerous locations, the weather resembled a spring day in April or May rather than the end of December.
A number of states broke historical records for December 25th warmth. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, topping the prior high mark of 22 degrees established over forty years ago. Urban centers like Austin, Dallas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.
Heat-Dome Effect Fuels Warmth
Above-average warmth is expected to continue on December 26th and into the weekend, with abnormal warmth projected to move across the southeastern US in the coming days.
The warmth has been fuelled by a robust atmospheric ridge reaching from the arid southwest across the continent, creating a heat-dome effect. This setup creates an extensive zone of high atmospheric pressure over a large portion of North America, trapping warm air near the surface. Sinking atmospheric air undergoes compression and additional heating, enabling abnormally high temperatures to develop.
