Arctic Blast Grips the Great White North as America Sees Hottest Christmas in History.
A prolonged deep freeze has enveloped a severe and lengthy Arctic outbreak, with thermometers lingering between -20C and -40C for weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, its coldest December temperature since 1975.
Enduring Chill in the Deep Minus Forties
In addition, the locales of Mayo and Dawson suffered through sixteen nights in a row colder than minus 40 degrees, with the temperature in Mayo bottoming out at -50.4 degrees Celsius at the start of the week. The capital, Whitehorse, likewise saw 10 nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
December 26th was anticipated to usher in minimum temperatures of at least minus 20C across many regions, from Edmonton in the west to Quebec in the east.
Expected to Continue For Days to Come
The severe cold is forecast to persist into the new year. There are warnings of possible electrical grid strain in Yukon territory over the next several days, as the territory’s power grid comes under strain from peak power usage levels.
The prolonged chill has been caused by the Arctic vortex settling above Canadian territory through December, which funnels frigid northern air southward. The frigid dome is projected to gradually withdraw north slowly, permitting warmer Pacific winds to flow over the United States and penetrate southern Canadian regions.
Dramatic Difference to American Heat
Conversely, sections of America recorded historically high temperatures for Christmas as temperatures soared about 15-30C above the seasonal average. In many areas, conditions felt more typical of April or May rather than the end of December.
A number of states broke historical records for December 25th warmth. In Oklahoma, Oklahoma City hit 25C on Tuesday, surpassing the previous peak of 22C set in 1982. Metropolitan areas such as Austin, Dallas, and Charlotte similarly saw thermometers rise past the 25C mark.
High-Pressure System Sustains High Temperatures
Unseasonable heat is predicted to persist on December 26th and into the weekend, with unseasonable heat forecast to sweep across the southeastern US in the coming days.
The warmth has been fuelled by a strong upper-level ridge extending from the desert south-west towards the north and east, establishing a classic heat-dome pattern. Such a configuration results in a widespread high-pressure system over a large portion of North America, which holds warm air close to the ground. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.
