We Escaped the Vortex This Time

(Baron/Lynx/Chronicle)

Some family members will be heading east to the Sierra mountains today, and we're lucky that California is out of the path of the polar vortex that is hitting much of the country.

The majority of the country will wake to bone-chilling temperatures Thursday, with dozens of temperature records at risk of being broken.

The massive outbreak of cold air is connected to the polar vortex, a lobe of frigid air that has broken away from the North Pole and settled over the middle of the country.

The shot of cold air won’t impact California or the West Coast. In the wake of a weak cold front that passed through Wednesday, a high-pressure ridge has developed near California, shielding the state from the cold air and from a powerful storm system set to drench the Pacific Northwest this weekend.

According to the National Oceanic and Atmospheric Administration (NOAA) the Arctic polar vortex

is a band of strong westerly winds that forms in the stratosphere between about 10 and 30 miles above the North Pole every winter. The winds enclose a large pool of extremely cold air. (There is an even stronger polar vortex in the Southern Hemisphere stratosphere in its winter.) The stronger the winds, the more the air inside is isolated from warmer latitudes, and the colder it gets.

A normal, stable polar vortex stays in the stratosphere above the Arctic, which gets extremely cold in the winter while we in the mid-latitudes experience warmer air and moderate winters. The polar vortex isn't always stable, however.

“We did have a sudden stratospheric warming in January,” explained [NOAA's Dr. Amy] Butler. “The polar vortex weakened. It got stretched out of shape and slid southward off the pole. Most of the time when this happens—and it happens on average about every other year in the Arctic—some part of the mid-latitudes will ultimately experience a cold air outbreak."

What causes the polar vortex to get "stretched out of shape" is the $64,000 question, and while some blame their favorite culprit, global warming, Dr. Butler refuses to take the bait: [bold added]

“I don’t think there is any convincing evidence of a long-term trend in the polar vortex. What we see in the record is this very interesting period in the 1990s, when there were no sudden stratospheric warming events observed in the Arctic. In other words, the vortex was strong and stable. But then they started back up again in the late 1990s, and over the next decade there was one almost every year. So there was a window of time in the early 2010s where it seemed like there might be a trend toward weaker, more disrupted or shifted states of the Arctic polar vortex. But it hasn’t continued, and more and more, it’s looking like what seemed to be the beginning of a trend was just natural variability, or maybe just a rebound from the quiet of the 1990s.”

Not only does the data not yet support the global-warming-causes-colder-winter hypothesis, the NOAA goes on to describe how leading climate models give conflicting results:

Some climate model experiments do predict that continued warming will lead to a weakening of the polar vortex...At the same time, other model simulations predict that warming and sea ice loss will lead to a stronger polar vortex.

I've decided to hold onto my internal-combustion-engine vehicles for a few more years; there's always a gas station nearby so I won't freeze to death in my car when another vortex hits, and I can't say the same for EV charging stations.