Meteorologists warn that an “extraordinary and unique” atmospheric event could reshape the 2025-2026 winter outlook. A rare, possible disruption of the polar vortex—which determines how cold it gets—or strengthening La Nina conditions—which influence where cold air travels—may significantly alter typical U.S. winter weather patterns, potentially leading to colder and snowier conditions than usual. A disruption of the polar vortex could send a blast of cold, arctic air into parts of the U.S.,