The National Weather Service reports patchy dense fog has developed across central Illinois Thursday morning. Abundant low level moisture from the rain that fell in the past 24 hours has allowed fog to develop across central Illinois. The fog is locally dense, reducing the visibility to 1/4 mile or less in spots. While widespread dense fog is not anticipated at this time, motorists should still be prepared for reduced visibilities in fog. Slow down and allow extra travel time Thursday morning.