A dense fog advisory will be in effect for northwest Iowa until 6am Monday. Areas of dense fog will persist through the overnight hours. Visibilities will drop below one quarter mile at times. This fog may begin to expand further north and west overnight, but is expected to improve by daybreak.
A dense fog advisory means visibilities will frequently be reduced to less than one quarter mile. If driving, slow down, use your headlights, and leave plenty of distance ahead of you.