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.

The arrival of an unsettled weather pattern will bring separate rounds of rain, including a Thanksgiving storm whose potential track and strength is still being monitored by forecasters. A cold front that will move through Tuesday,