Most of the country has enjoyed a relatively mild winter so far, but those cozy temperatures won’t last long. AccuWeather reports that the polar vortex could cause a “major shift in the weather pattern” during the second half of the season. In other words, it’s about to get very chilly.
While the phrase “polar vortex” sounds dramatic, it’s actually nothing out of the ordinary. This meteorological term describes the big mass of cold air that constantly hovers around the Arctic, spinning counterclockwise like a hurricane. The polar vortex usually remains above the North Pole, but occasionally it weakens. When that happens, it moves south and circulates above the United States—bringing a whole lot of Arctic air with it.