A powerful winter storm system moving across the Great Lakes and Northeast is bringing snow and ice, frigid temperatures and possible whiteout conditions.

A potent winter storm threatened blizzard-like conditions, treacherous travel and power outages in parts of the Upper Midwest as other areas of the country braced Monday for plunging temperatures, strong winds and a mix of snow, ice, and rain.

A wave of arctic air is infiltrating the United States, but forecasters say it will soon clear out in a warmup that will send temperatures soaring before Christmas. A winter storm is expected to bring light to moderate snow across much of the central and ...