Deep Freeze Tightens Hold on the Great White North as America Sees Hottest Christmas in History.
An intense cold spell has seized a bitter and extended period of frigid weather, with temperatures hovering from 20 to 40 degrees below zero for multiple weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading in nearly five decades.
Enduring Chill Below -40C
In addition, the locales of Mayo and Dawson suffered through over two straight weeks of nights below -40C, with Mayo plunging to -50.4C at the start of the week. Whitehorse also recorded 10 nights when readings fell to minus 30 degrees or lower.
The deep freeze spread farther south during the holiday season. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.
Boxing Day was expected to bring readings no higher than -20 Celsius through a wide swath, including Edmonton, Montreal, Ottawa and Quebec.
Forecast to Persist Through Early January
The frigid conditions are predicted to linger for the foreseeable future. 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 prolonged chill has been caused by a stationary polar vortex across the northern part of the continent this month, allowing bitter Arctic air to spill south. In the coming week, forecasts indicate this cold air will pull back northward allowing more temperate air from the Pacific to sweep across America and reach into portions of southern Canada.
Stark Contrast Compared to Stateside Temperatures
Conversely, sections of America recorded their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. 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, surpassing the previous peak of 22C set in 1982. Metropolitan areas such as Austin, Dallas, and Charlotte also logged readings above 25 degrees Celsius.
Atmospheric Ridge Sustains High Temperatures
Unseasonable heat is predicted to persist through Boxing Day and the days ahead, with unseasonable heat forecast to sweep across the southeastern US in the coming days.
The unseasonable temperatures are powered by a strong upper-level ridge reaching from the arid southwest across the continent, creating a heat-dome effect. This pattern establishes a broad area of high pressure across much of the continent, trapping warm air near the surface. Descending air compresses and adiabatically warms, enabling abnormally high temperatures to develop.
