Polar vortex patterns explain shifting US winter cold despite warming climate

Despite a warming climate, bone-chilling winter cold can grip parts of the U.S. In a study appearing in Science Advances, researchers found that two specific patterns in the polar vortex, a swirling mass of cold air high in the stratosphere, steer extreme cold to different regions of the country. One pattern drives Arctic air into the Northwest U.S., the other into the Central and Eastern areas.