Polar Vortex: What it is and how it affects cold weather in the United States | Sciences

Polar Vortex: What it is and how it affects cold weather in the United States |  Sciences

As the United States experiences extremely cold temperatures, some weather commentators are mentioning the polar vortex, an area of ​​rotating winds in the Arctic. They say a possible malfunction in its system may be responsible for the cold winds in the northern states of the country.

What is a polar vortex?

The Arctic polar vortex is a band of winds that forms in the stratosphere between “about 10 and 30 miles above the North Pole each winter,” according to the National Oceanic and Atmospheric Administration. These winds contain a large amount of very cold air, which becomes even colder if the winds intensify, as inland air is isolated from warmer latitudes. While it weakens during the summer, it becomes stronger in the winter. The National Weather Service says it’s called a vortex because of “counterclockwise airflow that helps keep cool air near the poles.” Not all cold weather comes from the polar vortex, as cold air is typically kept in the polar regions and it takes “unusual conditions” for the flow to migrate this far south.

Often during the winter, as the polar vortex expands, it sends cold air south with the polar jet stream, which is associated with large flows of cold Arctic air in the United States. The jet stream occurs in the troposphere, 5 to 9 miles above the Earth’s surface. While some credit the polar vortex for the weather, “it is the polar jet stream that plays a large role in our daily winter weather,” according to NOAA.

Cold air from the jet stream is causing not only a surge in cold air in the United States, but also in Canada (obviously) and parts of Europe and Asia. When the vortex is strong, it keeps the jet stream balanced around the Earth, making the weather work “normally.” However, when the vortex disrupts and weakens, the system can break, pushing cold air southward, causing colder weather in northern regions.

Some scientists have highlighted that recent climate change in the Arctic is disrupting the polar vortex, causing more cold air to enter the United States. Christina Dahl, a scientist at the Union of Concerned Scientists, said: American Scientific The fact that 2023 was the hottest year on record could be linked to an increase in cold temperatures: “Climate change is causing all kinds of different impacts and some of them are counterintuitive.” Some studies have shown this type of association with cold North American winters. However, other experts have questioned this theory, saying there is not enough evidence to confirm it. However, other studies have indicated that the loss of ice caused by global warming could lead to a stronger polar vortex.

Polar vortex in 2024

The United States is currently experiencing a severe cold snap due to the first large Arctic air mass of 2024. According to meteorologist Laura Siasto and meteorologist Amy Butler of the National Oceanic and Atmospheric Administration (NOAA), the stratospheric polar vortex has exhibited unusual behavior, with little disturbance Closer to the North Pole. The stratosphere borders the troposphere, causing the vortex to split into two lobes. Disturbances in the lower stratosphere have already contributed to the outbreak of cold air over North America. While the complete collapse of the polar vortex is expected to be short, impacts on the tropospheric jet stream and weather patterns could persist, increasing the possibility of cold air outbreaks in the coming weeks. Experts highlight that the polar vortex is one of many factors that influence the weather, and other elements such as the El Niño phenomenon also play a role.

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