Arctic Blast Grips the Great White North as United States Experiences Warmest Christmas Ever.
Northern Canada has been gripped by a severe and lengthy Arctic outbreak, with thermometers lingering between -20C and -40C for weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, its coldest December temperature in nearly five decades.
Consecutive Nights of Extreme Cold
Meanwhile, Mayo and Dawson endured 16 consecutive nights colder than minus 40 degrees, with Mayo plunging to -50.4C earlier this week. Whitehorse also recorded ten separate nights when the cold dipped under -30 Celsius.
This Arctic air mass pushed further southward 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, encompassing cities from Edmonton to Quebec.
Forecast to Persist into the New Year
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 record-high energy demand.
This extended freeze is the result of the polar vortex remaining anchored over Canada for much of December, allowing bitter Arctic air to spill south. Next week, the cold air mass is expected to retreat north allowing more temperate air from the Pacific to sweep across the US and into parts of southern Canada.
Pronounced Disparity with US Warmth
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.
A number of states broke historical records for December 25th warmth. In Oklahoma, Oklahoma City hit 25C on Tuesday, topping the prior high mark of 22 degrees established over forty years ago. Metropolitan areas such as Austin, Dallas, and Charlotte also logged readings above 25 degrees Celsius.
High-Pressure System Drives the Heat
Above-average warmth is expected to continue on December 26th and into the weekend, with atypical high temperatures expected to spread across the southeastern US in the coming days.
The unseasonable temperatures are powered by a powerful high-altitude ridge reaching from the arid southwest across the continent, creating a heat-dome effect. Such a configuration results in a widespread high-pressure system blanketing a significant part of the landmass, trapping warm air near the surface. Descending air compresses and adiabatically warms, enabling abnormally high temperatures to develop.