Dense fog has formed over portions of southeast Iowa and western Illinois as of this afternoon. These locations can expect visibilities to remain very low through the night, though some temporary improvement may occur at times as a few rain showers pass by this evening. A strong cold front will end the fog before the morning commute hours Tuesday.
A dense fog advisory will be in effect through 5am CST. Visibilities will be under 1/4 of a mile. Fog will become more widespread through this evening and continue until a cold front sweeps through the area early Tuesday morning.