Arctic Blast Grips the Great White North as United States Experiences Most Unseasonably Mild Christmas Ever.
A prolonged deep freeze has enveloped an intense and prolonged cold spell, with temperatures hovering from 20 to 40 degrees below zero for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, its coldest December temperature since 1975.
Consecutive Nights Below -40C
In addition, the locales of Mayo and Dawson suffered through over two straight weeks of nights below -40C, with the temperature in Mayo bottoming out at -50.4 degrees Celsius at the start of the week. The capital, Whitehorse, likewise saw ten separate nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south over the festive period. Christmas night saw Edmonton's temperatures plummet below minus 28C.
The day after Christmas was forecast to deliver lows of at least -20C across many regions, encompassing cities from Edmonton to Quebec.
Expected to Continue into the New Year
The frigid conditions are predicted to linger through the start of January. Officials have warned that the Yukon could face electricity outages soon, as its energy infrastructure faces unprecedented demand from peak power usage levels.
The lengthy cold snap originates from the Arctic vortex settling over Canada for much of December, which funnels frigid northern air southward. The frigid dome is projected to gradually withdraw north allowing more temperate air from the Pacific to sweep across America and reach into portions of southern Canada.
Pronounced Disparity to American Heat
Conversely, sections of America recorded the hottest December 25th in their history as the mercury climbed roughly 15 to 30 degrees above typical averages. For numerous locations, the weather resembled a spring day in April or May than late December.
Multiple states established new Christmas temperature highs. The capital of Oklahoma soared to 25C on Christmas Day, surpassing the previous peak of 22C set in 1982. Urban centers like Austin, Dallas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.
Atmospheric Ridge Sustains High Temperatures
Warmer-than-normal conditions are forecast to last for the remainder of the week and beyond, with atypical high temperatures expected to spread into the south-eastern states later in the week.
The warmth has been fuelled by a strong upper-level ridge reaching from the arid southwest across the continent, establishing a classic heat-dome pattern. Such a configuration results in a widespread high-pressure system across much of the continent, which holds warm air close to the ground. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.
