Polar vortex 2019 usa5/18/2023 ![]() The warm air in the lower atmosphere, as well as cooler air, block the straight-flowing winds of the jet stream, like atmospheric bumper cars. ![]() He found that it’s typically over Siberia or the North Atlantic that “zones” of warm air funnel up into the stratosphere. in 2018, he began researching the origin of these Arctic disruptions to make better long-term predictions earlier in the season. After a cold snap sent demand for heat skyrocketing and caused a natural gas shortage in the U.K. Stratospheric warming events themselves still aren’t that well understood, says Michael Ventrice, a meteorologist for The Weather Company, a forecasting firm. ![]() Such stratospheric warming events are common, but major disruptions like that one typically only happen about every other year, says Judah Cohen, the director of seasonal forecasting at Atmospheric and Environmental Research, a company that advises government agencies and the private sector on weather risks. On January 4, scientists detected the sudden stratospheric warming over Siberia. If the temperatures become too close-and a sharp warming will do that-it starts to wander off its path and head south, pushing the lower vortex ahead of it. That polar vortex requires a stable temperature difference with the one below it to keep it in its lane above the North Pole. While both systems can influence our weather, it’s a disruption to the vortex in the stratosphere that may now send winter weather our way. It’s much smaller than the vortex below it, and typically spins west to east above the North Pole. In the atmospheric layer above it, about 10 to 30 miles up, is the stratospheric polar vortex, where every winter a sunlight-starved Arctic spins up a mass of cold air that, ultimately, dissipates in the spring. It’s large, often dipping into the mid-latitudes, the region above the tropics and below the Arctic-in North America, think central Mexico to northern Canada-and moving west to east. In the lowest layer of the atmosphere, the troposphere-where weather occurs-there spins a polar vortex that circles the globe year round, a jet stream that’s also sometimes referred to as the circumpolar vortex. When “polar vortex” appears in the news, it can refer to one of two different, but related, weather patterns. What is a polar vortex and how does it work? It’s expected to arrive in the next week or two and could last, in fits and spurts, into February. Midwest and Northeast and the mid-latitude regions of Europe. ![]() The result of this disruption could mean frigid winter weather pummelling the U.S. The mass of extremely warm air threw the freezing polar vortex out of balance, shoving it off its North Pole axis so forcefully that it in effect split in two, as if growing a pair of legs: one over North America and one over Europe. While these “sudden stratospheric warming” events happen to some extent every year, this one is categorized as a major event and is less common. In the first week of January, they increased from about minus 92 degrees Fahrenheit to 8 degrees Fahrenheit. Specifically, temperatures high in the stratosphere above Siberia. Their wait might soon be over-and if you’re not a meteorologist, you may be surprised to learn that it’s because of a recent spike in Arctic temperatures. Every year, weather enthusiasts eagerly watch and wait for signs that the polar vortex, a mass of cold air spinning around the Arctic, might meander south, sending cold and snow into the lower latitudes.
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