Localized patchy dense freezing fog has formed in central Oregon, north central Oregon, the Ochoco-John Day Highlands, the southern Blue Mountains and Foothills. Dense freezing fog will be most likely over mountain passes and higher terrain where a low stratus cloud deck is meeting the higher terrain. Patchy dense freezing fog may also occur in local sheltered spots. Most areas will remain fog free. The fog may persist through the morning hours. If you need to travel, be prepared for sudden drops in visibility to a quarter mile. Slow down and use your low beam headlights. Do not use your high beam headlights.