South Mississippi motorists will face hazardous driving conditions until 9 a.m. Monday due to dense fog.
Patchy fog will then obscure visibility in some areas until about 10 a.m., according to the National Weather Service in New Orleans.
The alert includes Harrison, Jackson, Hancock counties.
Visibility will be a quarter-mile or less, according to the Mississippi Department of Transportation.
Also included are Pearl River, Amite, Walthall and Wilkinson counties, MDOT said in a news release.
Drivers are encouraged to use their low-beam lights and to reduce speed to help prevent accidents.