Prolonged Chill Grips Canada as US Records Hottest Christmas in History.
An intense cold spell has seized a severe and lengthy Arctic outbreak, with temperatures hovering in the minus 20 to minus 40 Celsius range for weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, representing its most frigid December day since 1975.
Consecutive Nights Below -40C
Meanwhile, Mayo and Dawson endured sixteen nights in a row dipping under the minus 40 Celsius threshold, with Mayo plunging to -50.4C on Monday. The capital, Whitehorse, likewise saw a series of ten nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south through Christmas week. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
Boxing Day was expected to bring lows of at least -20C across many regions, from Edmonton in the west to Quebec in the east.
Expected to Continue into the New Year
The severe cold is forecast to persist into the new year. There are warnings of possible electrical grid strain in Yukon territory soon, as its energy infrastructure faces unprecedented demand from historically high electricity consumption.
The lengthy cold snap originates from the polar vortex remaining anchored above Canadian territory through December, which funnels frigid northern air southward. Next week, the cold air mass is expected to retreat north slowly, permitting warmer Pacific winds to flow over the US and into parts of southern Canada.
Dramatic Difference with US Warmth
Conversely, sections of America recorded their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. Across wide regions, the atmosphere was more akin to late spring rather than the end of December.
A number of states broke historical records for December 25th warmth. The capital of Oklahoma soared to 25C on Christmas Day, exceeding the old record of 22C from 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.
High-Pressure System Drives the Heat
Warmer-than-normal conditions are forecast to last for the remainder of the week and beyond, with unseasonable heat forecast to sweep into the south-eastern states later in the week.
The warmth has been fuelled by a robust atmospheric ridge reaching from the arid southwest across the continent, establishing a classic heat-dome pattern. This setup creates an extensive zone of high atmospheric pressure over a large portion of North America, trapping warm air near the surface. Descending air compresses and adiabatically warms, allowing unusually warm temperatures to build.
