Winter 'heat dome' builds in the West, but you wouldn’t know it

Winter 'heat dome' builds in the West, but you wouldn’t know it
Winter 'heat dome' builds in the West, but you wouldn’t know it

A historic ridge is peaking over the West Coast of North America, but you wouldn't know it. The late-fall impacts are more muted, as the amount of solar energy available is a fraction of what is obtainable in June.

The satellite imagery is eerie from June 2021. It was anything but calm on the surface. The heat increased day after day, and that vicious feedback effect produced deadly consequences.

SEE ALSO: Nearly all of Canada will face an icy chill due to building high pressure

june2021
june2021

This November and June 2021 share a similar anomaly in the upper atmosphere. If you compare both ridges using a standardized anomaly, the heat dome peaked at over four standard deviations from normal.

2021
2021

November 2022, the height of the ridge -- an elongated region of high pressure in the upper atmosphere -- peaks at over four standard deviations across the Yukon this week.

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2022

The impacts are far from extreme because we're working with around six hours of daylight under the northern ridge, but the surface temperature anomalies are still troubling. Northern Alaska and the Arctic Ocean surge above the freezing mark, touching 20°C above normal.

comparechart
comparechart

Farther down the coast, the anomalies were above the ground. It's called an inversion, and 1500 metres above sea level, temperatures spilled into the low teens while the lower elevations faced low clouds and fog.

Low clouds are locked in like cement in these setups for interior valleys, blocking the sun from warming up the valley bottoms. It's one of those unusual paradoxes you get in the fall and winter. As the strength of the ridge increases and temperatures aloft warm, the result is chilly and even below-seasonal temperatures at the surface.

nov2022
nov2022