The National Weather Service said the fog could lead to black ice and limited visibility, and urged drivers to exercise caution.

North Georgians woke up to thick fog Sunday morning. That fog also caused more than 1,000 delays at the Atlanta airport.

The advisory had been issued for Madison, Marshall, Jackson and DeKalb counties. "Temperatures have warmed above freezing and most of the dense fog has lifted. Therefore the threat for freezing fog has ended," says the National Weather Service.

NWS meteorologist Matthew Day told Newsweek that freezing fog is an "unusual" occurrence for the Norman, Oklahoma, NWS office, which issues forecasts for north Texas as well. Although dense fog is normal for the region this time of year, temperatures aren't always cold enough to cause the fog to freeze.

Despite the morning fog, it is expected to get clearer through the day with temperatures reaching a high near 57.

Keep both hands on the wheel and go slow in north Alabama this morning. The National Weather Service in Huntsville has issued a freezing fog advisory for part of the region, and it will be in effect until 9 a.m. Sunday. The Alabama counties affected are Madison, Marshall, DeKalb and Jackson.

A thick sheet of fog settled in around metro Atlanta on Sunday. FOX LOCAL's Judayah Murray breaks down what's at stake, including your flight, with FOX 5 Storm Team meteorologist Joanne Feldman.

Rhapsody, Enchantment, and Grandeur of the Seas are all delayed due to fog in Tampa Bay. The delays are at least 8 hours long for the fog to clear and the ships to reach their terminals. Guests will be notified if there is any need for itinerary changes due to the delays.