Tonight’s updated weather story from the National Weather Service:
Patches of fog with visibilities less than 1 mile are possible
(October 6, 2015) – An update on the weather tonight: Fog is already developing in the northwest near Lake Michigan, with some locations seeing visibility below 1 mile. We expect fog to develop overnight, but are uncertain as to far eastward it will spread. Right now, we think most areas will see visibility between 1 and 3 miles. However, as is already seen in the northwest, patches of fog with visibilities less than 1 mile are possible. Stay tuned for updates. If driving, take it slow and use low-beam headlights.