A fresh blast of Arctic air is poised to spill across a wide swath of the United States, and the latest polar vortex map makes clear which regions are most exposed. Forecast models show a sharp southward dip in the jet stream that will funnel frigid air from Canada into the central and eastern states,

A monster winter storm is sweeping across much of the U.S. through this weekend, dumping up to a foot of snow onto the New York City area and unleashing havoc across the country. It’ll also be one of the biggest snowstorms for New York City in recent years.