...AREAS OF DENSE FOG AFFECTING THE FOX VALLEY AND LAKESHORE AREAS... Areas of dense fog, with visibilities of 1/4 mile or less, will affect the Fox Valley and lakeshore areas, including Interstate 41, through about 9 am. Locally very poor visibility of around 100 yards may occur in some areas.
Current Watches, Warnings and Advisories for Brown (WIC009) Wisconsin Issued by the National Weather Service
https://alerts.weather.gov/cap/wwacapget.php?x=WI12641196C648.SpecialWeatherStatement.126411970720WI.GRBSPSGRB.eca529a4772a892ee50e8da33e3e4a70