Think Dallas-Fort Worth has had enough Arctic blasts? Wait for the wrath of polar vortex

Dallas-Fort Worth has endured wild swings in the weather in January — from frigid temperatures, a dusting of snow then a warming trend and a bit of rain. But winter may not be done with us yet. An unpredictable polar vortex may still have a say in how miserable our winter can become.

As swaths of the U.S. Midwest and Northeast had to dig out from massive snowstorms, North Texas felt the sting of Arctic blasts that chilled the region down to the low teens for a few days. The cold air sucked up condensation from warmer area lake waters resulting in a thin dusting of snow across Dallas-Fort Worth — a phenomenon called “lake effect snow” normally associated with areas along the Great Lakes.

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Thirty states were included in alerts for dangerously low temperatures and wind chills in the past week with readings dropping to minus-16 in Kansas City, 1 degree in Oklahoma City, minus-10 in Chicago and minus-27 in Bismarck, N.D. Snow cover reached its greatest mid-January extent over the contiguous United States in the last 20 years.

The disruption of the polar vortex early in January is partly to blame for the cold spell we experienced.

“A disrupted polar vortex increases the odds that the tropospheric jet stream will stay shifted farther south, which increases the risk for cold air outbreaks,” according to the Polar Vortex Blog by Laura Ciasto and Amy Butler on the website Climate.gov.

So, what exactly is the polar vortex?

The polar vortex is extensive coverage of low pressure and cold air surrounding Earth’s poles. When the vortex is strong and stable, the polar jet stream shifts northward, keeping the cold air in the Arctic. But when the vortex weakens or is disrupted, the jet stream often becomes extremely wavy, allowing warm air to flood into the Arctic and polar air to sink down into the mid-latitudes.

We’ve seen this phenomenon in action. The polar vortex played a role in the extreme winter weather outbreak that struck Texas in February 2021, UN weather experts said.

“We did have a sudden stratospheric warming in January,” explained Butler, a NOAA stratosphere expert. “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. The disruption of the vortex encouraged the polar jet stream to become wavier for several weeks, and in combination with other weather patterns, created favorable conditions for a severe cold air outbreak in the central U.S.”

Here’s what Texas can expect from a capricious polar vortex

It does seem like we are seeing the effects of the polar vortex more regularly. The last time Texas was in the grip of the weather event was in December 2022.

Global warming has increased the number of polar vortex outbreaks, a study found. While they used to only happen once every other year or so, the research shows they are now close to happening yearly, if not more, said study lead author Judah Cohen, a winter storm expert for Atmospheric Environmental Research. The number of times the polar vortex has weakened per year has more than doubled since the early 1980s.

And lately, the polar vortex has been acting erratic, climate experts say.

“If we had to characterize the behavior of the stratospheric polar vortex over the last week, we’d say it’s acting … squirrely,” according to the Polar Vortex Blog. “Living up to the celebrity status we bestowed upon it, the stratosphere seems to know everyone is watching and has decided to do something unexpected.”

This could mean more winter snow and ice for Texas as the jet stream is pushed farther south than normal.

“This ‘loading of the dice’ for cold air can persist for up to 6 weeks after the vortex is disrupted, making these events relevant for weather timescales, but also for longer sub-seasonal forecasts,” Climate.gov says.