Dense fog will that developed overnight will be widespread by daybreak, the weather service reported.
Counties affected by the advisory include Lucas, Wood, Ottawa, Sandusky, Erie (OH), Lorain, Cuyahoga, Hancock, Seneca, Huron, Medina, Wyandot, Crawford, Richland, Ashland, Wayne, Marion, Morrow, Holmes and Knox.
This includes the cities of Toledo, Bowling Green, Port Clinton, Fremont, Sandusky, Lorain, Cleveland, Findlay, Tiffin, Norwalk, Medina, Upper Sandusky, Carey, Bucyrus, Mansfield, Ashland, Wooster, Marion, Mount Gilead, Millersburg, and Mount Vernon.
Visibility may be limited to a quarter mile or less with conditions improving after daybreak. Motorists are advised to use caution and slow down as objects will be seen only at close range.
Several area schools are operating on a delayed schedule this morning. CLICK HERE for a full list.