Deep Freeze Grips the Great White North as America Sees Most Unseasonably Mild Christmas Ever.
An intense cold spell has seized a severe and lengthy Arctic outbreak, 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 in half a century.
Consecutive Nights in the Deep Minus Forties
Similarly, the communities of Mayo and Dawson experienced 16 consecutive nights colder than minus 40 degrees, with the temperature in Mayo bottoming out at -50.4 degrees Celsius on Monday. The capital, Whitehorse, likewise saw ten separate nights when readings fell to minus 30 degrees or lower.
This Arctic air mass pushed further southward over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
December 26th was anticipated to usher in minimum temperatures of at least minus 20C in numerous areas, encompassing cities from Edmonton to Quebec.
Expected to Continue into the New Year
The severe cold is forecast to persist through the start of January. Officials have warned that the Yukon could face electricity outages in the coming days, as the system endures record-high pressure from peak power usage levels.
The lengthy cold snap originates from a stationary polar vortex above Canadian territory through December, which funnels frigid northern air southward. 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
In stark contrast, parts of the US experienced their warmest Christmas Day on record as temperatures soared about 15-30C above the seasonal average. Across wide regions, the atmosphere was more akin to late spring than late December.
A number of states broke historical records for December 25th warmth. 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 similarly saw thermometers rise past the 25C mark.
High-Pressure System Sustains High Temperatures
Unseasonable heat is predicted to persist on December 26th and into the weekend, with atypical high temperatures expected to spread across the southeastern US in the coming days.
The warmth has been fuelled by a powerful high-altitude ridge stretching from the southwestern deserts northward and eastward, creating a heat-dome effect. Such a configuration results in a widespread high-pressure system blanketing a significant part of the landmass, which holds warm air close to the ground. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.