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.

Weather impacts are unfolding across the U.S. as millions travel for Thanksgiving this week. In the west, snow and freezing temperatures could impact flights. By Thanksgiving morning, a low will bring heavy rain into the Northeast with possible snow in higher elevations.