Saturday, September 04, 2021

In the Arctic, Less Sea Ice and More Snow on Land Are Pushing Cold Extremes to Eastern North America


https://insideclimatenews.org/news/02092021/arctic-polar-vortex-ice-snow-extreme-freeze/?utm_source=InsideClimate+News&utm_campaign=35bc5d7cb9-&utm_medium=email&utm_term=0_29c928ffb5-35bc5d7cb9-328507972

 

By Bob Berwyn
September 2, 2021

 

New research shows that Arctic climate changes during the next few weeks may determine if and when the Eastern United States gets another extreme cold wave this coming winter.

Since the 1980s, Arctic sea ice extent has been dropping sharply, while the extent of land covered by snow in Siberia during autumn has increased. Those changes have combined to more frequently contort the “polar vortex” of high-altitude Arctic winds into a dumbbell shape that increases the potential for severe winter weather outbreaks like February’s Texas freeze, the study, published in Science Thursday, shows.

Arctic sea ice this year is once again near a record low, and medium range forecasts call for relatively cold and snowy conditions in Siberia, potentially setting the stage for renewed winter extremes at lower latitudes.

Disruptions of the polar vortex—a belt of strong, high altitude winds usually circling the central Arctic—have become more frequent in the last 40 years, the new research found. In the study, the researchers write that the lack of sea ice in the Barents-Kara Seas and heavier snowfall over Siberia combine to build a wave of high pressure in the atmosphere between Northern Europe and the Ural Mountains, along with low pressure over East Asia.


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