OKLAHOMA CITY — Heavy fog has closed Will Rogers World Airport to arriving aircraft.

Airport spokesman Mark Kranenburg said fog moved in about noon Thursday at the Oklahoma City airport and reduced visibility below the minimum for aircraft to land.

Departing flights have also been disrupted.

Kranenburg said airport officials were taken by surprise when the fog proved so heavy that visibility was reduced to less than a thousand feet.

The National Weather Service issued a dense fog advisory for the central portion of Oklahoma.

Foggy conditions were being caused by warm and humid air surging north from the Gulf of Mexico as a storm system approached the state.

The weather service said a cold front will move in this evening, putting an end to the foggy conditions.