A winter storm that brought snow, sleet and freezing rain to a large swath of the Midwest swept into the mid-Atlantic and Northeast on Thursday, causing treacherous travel conditions, prompting school delays and closures and potential power outages for millions of Americans.

Punxsutawney Phil made his annual prediction in Pennsylvania, and the groundhog saw a shadow, meaning the United States is set for six more weeks of winter.

Snow arrives between 6 and 10 a.m. Thursday and will fall for most of the morning. Given cold temperatures, National Weather Service forecasters say flakes could accumulate quickly with moderate to heavy snowfall expected.