Dense fog advisory until 9 a.m.

The National Weather Service has issued a dense fog advisory until 9 a.m. for north and west Illinois.

Officials from the weather center said the heavy fog will reduce visibility to one quarter mile or less in Kane, McHenry, and DuPage counties. The foggy conditions are expected to improve by midmorning, the National Weather Service is announcing on their website.

The low visibility could result in hazardous driving in some areas, and possible longer travel times, officials said.

People who will be driving are urged to reduce speeds, use headlights to help other drivers to see you, and leave plenty of distance in front of you.