Moisture is moving up out of Missouri along with slightly warmer temperatures. Dense fog is developing as this moisture moves over the cooler ground. A cold front will push through the region later this evening though tonight. The strong winds and colder air will produce improving conditions later tonight.
A dense fog advisory will be in effect until 10pm across south central Iowa and until 5am for southeast Iowa. Visibilities will be 1/4 of a mile or less.