A storm that was pounding California's Sierra Nevada with snow Tuesday took aim at the Colorado Rockies and could roll east and slam the Appalachians on Thanksgiving Day, bringing unsettled travel weather to millions of Americans hitting the skies and roads for the holiday weekend.

A high-impact winter storm packing heavy snow and rain has moved into the Northeast, leading to last-minute travel troubles as millions of people across the U.S. gather with family and friends on Thanksgiving to celebrate the holiday.

Parts of New York, Vermont, New Hampshire and Maine are under winter storm warnings, and precipitation is expected to begin as early as 1 a.m. on Thanksgiving Day. Higher elevations, including area ski resorts, will see snowfall that could continue through 1 a.m. on Black Friday.

Affected areas will see varying precipitation and cold temperatures. Storms which hit California and Nevada in the Sierra Nevada Range on Tuesday moved into Colorado and Utah on Wednesday,

Winter weather could snarl travel plans for the millions of Americans traveling for the Thanksgiving holiday this year.

Travelers already at their holiday destinations have much to be thankful for as a Thanksgiving Day storm dumps snow and rain on the East Coast, creating travel woes for thousands still on their journeys.

Rain is falling across the northeast on Thursday morning, setting up what's bound to be a soggy Thanksgiving for dozens of states.

Besides a storm brewing over the Great Lakes, a "bomb cyclone" is also forming off the Northwest, promising widespread snow.