The polar vortex is a large area of cold, spinning air that sits near the North Pole and exists year-round. When it weakens or shifts, Arctic air can spill south, increasing the risk of snow and ...

Polar vortexes are a year-round phenomenon. But Chicago-area residents only notice them when they collapse, experts say. That’s what’s happening starting Thursday when dangerously frigid air from ...

The Great Lakes and Northeast are bracing for another cold shot later this month — down to single digits in places. How cold will it get in NY?