We’re at the time of year when “advection” fog becomes common. This occurs as warm, humid air well to our south travels northward over the cooler waters of the Northern Gulf. The air is cooled a bit to the dew point, resulting in fog. At night, without the heating from the sun, the fog is “advected”, or blown, over land. This results in areas of dense fog, especially for the parishes bordering the Gulf. Watch out for dense fog Wednesday morning, with the threat to return for Thursday and Friday mornings.