With Thanksgiving holiday travel well underway, many have reached their destinations — but for everyone else, a storm tracking from the Rockies to the Midwest and Northeast into tomorrow will bring rain and snow,

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.

Millions of drivers and air travelers may face severe weather and long lines over the next few days. More than 50,000 flights are expected to take off on Tuesday, one of the busiest travel days.