Prolonged Chill Grips Canada as America Sees Most Unseasonably Mild Christmas Ever.
A prolonged deep freeze has enveloped a severe and lengthy Arctic outbreak, with temperatures hovering between -20C and -40C for an extended duration. On Tuesday, Braeburn in the Yukon recorded -55.7C, representing its most frigid December day since 1975.
Enduring Chill Below -40C
Meanwhile, Mayo and Dawson endured 16 consecutive nights below -40C, with Mayo plunging to -50.4C at the start of the week. Whitehorse similarly reported a series of ten nights when temperatures dropped below -30C.
The bitter chill extended its reach south through Christmas week. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.
The day after Christmas was forecast to deliver minimum temperatures of at least minus 20C in numerous areas, including Edmonton, Montreal, Ottawa and Quebec.
Likely to Linger For Days to Come
The frigid conditions are predicted to linger into the new year. There are warnings of possible electrical grid strain in Yukon territory over the next several days, as its energy infrastructure faces unprecedented demand from record-high energy demand.
The prolonged chill has been caused by the polar vortex remaining anchored over Canada for much of December, which funnels frigid northern air southward. In the coming week, forecasts indicate this cold air will pull back northward allowing more temperate air from the Pacific to sweep across the US and into parts of southern Canada.
Dramatic Difference to American Heat
Conversely, sections of America recorded their warmest Christmas Day on record as temperatures soared about 15-30C above the seasonal average. Across wide regions, the atmosphere was more akin to late spring instead of the heart of winter.
Several states set Christmas Day temperature records. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, surpassing the previous peak of 22C set in 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.
High-Pressure System Drives the Heat
Above-average warmth is expected to continue through Boxing Day and the days ahead, with abnormal warmth projected to move across the southeastern US in the coming days.
The unseasonable temperatures are powered by a powerful high-altitude 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, allowing unusually warm temperatures to build.
