Prolonged Chill Grips the Great White North as US Records Most Unseasonably Mild Christmas Ever.
Northern Canada has been gripped by a severe and lengthy Arctic outbreak, with thermometers lingering from 20 to 40 degrees below zero for multiple weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, representing its most frigid December day since 1975.
Prolonged Freeze in the Deep Minus Forties
In addition, the locales of Mayo and Dawson suffered through 16 consecutive nights colder than minus 40 degrees, with Mayo plunging to -50.4C at the start of the week. The capital, Whitehorse, likewise saw ten separate nights when readings fell to minus 30 degrees or lower.
The bitter chill extended its reach south over the festive period. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.
Boxing Day was expected to bring lows of at least -20C across many regions, encompassing cities from Edmonton to Quebec.
Forecast to Persist For Days to Come
This harsh winter weather is expected to continue through the start of January. Officials have warned that the Yukon could face electricity outages soon, as its energy infrastructure faces unprecedented demand from record-high energy demand.
This extended freeze is the result of the polar vortex remaining anchored over Canada for much of December, which funnels frigid northern air southward. Next week, the cold air mass is expected to retreat north gradually, enabling milder Pacific air to move across the United States and penetrate southern Canadian regions.
Stark Contrast to American Heat
In stark contrast, parts of the US experienced the hottest December 25th in their history as the mercury climbed roughly 15 to 30 degrees above typical averages. In many areas, conditions felt more typical of April or May rather than the end of December.
Several states set Christmas Day temperature records. 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 were also among those that recorded temperatures above 25C.
High-Pressure System Drives the Heat
Unseasonable heat is predicted to persist on December 26th and into the weekend, with atypical high temperatures expected to spread into the south-eastern states later in the week.
The unseasonable temperatures are powered by a robust atmospheric 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. Descending air compresses and adiabatically warms, enabling abnormally high temperatures to develop.
