Prolonged Chill Envelops Canada as America Sees Most Unseasonably Mild Christmas in History.
A prolonged deep freeze has enveloped an intense and prolonged cold spell, with thermometers lingering between -20C and -40C for an extended duration. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, representing its most frigid December day since 1975.
Consecutive Nights Below -40C
Meanwhile, Mayo and Dawson endured 16 consecutive nights colder than minus 40 degrees, with Mayo experiencing a low of -50.4C on Monday. Whitehorse similarly reported 10 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 lows of at least -20C through a wide swath, from Edmonton in the west to Quebec in the east.
Likely to Linger 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 record-high energy demand.
The prolonged chill has been caused by a stationary polar vortex 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 America and reach into portions of southern Canada.
Dramatic Difference Compared to Stateside Temperatures
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.
Several states set Christmas Day temperature records. In Oklahoma, Oklahoma City hit 25C on Tuesday, surpassing the previous peak of 22C set in 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina also logged readings above 25 degrees Celsius.
High-Pressure System Sustains High Temperatures
Above-average warmth is expected to continue on December 26th and into the weekend, with abnormal warmth projected to move into the south-eastern states later in the week.
The warmth has been fuelled by a powerful high-altitude ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. Such a configuration results in a widespread high-pressure system over a large portion of North America, trapping warm air near the surface. As air sinks through the atmosphere, it compresses and heats further, enabling abnormally high temperatures to develop.
