North Bay Interior Valleys under Dense Fog Advisory Until Friday Morning
On Friday, the National Weather Service (NWS) in San Francisco, CA, issued a dense fog advisory in effect until 10 a.m. for the North Bay Interior Valleys.
Fog Conditions and Impact
The NWS warns of visibility of one quarter mile or less due to dense fog, which could create hazardous driving conditions.
"Low visibility could make driving conditions hazardous," says the NWS. "If driving, slow down, use your headlights, and leave plenty of distance ahead of you."
Advisory Details
The advisory remains in effect until 10 a.m. It is issued when widespread dense fog develops, causing visibility frequently to drop to one-quarter of a mile or less, making travel difficult.
Safety Recommendations for Driving in Fog
- Reduce speed to ensure safe stopping distance
- Use headlights (not high beams) to improve visibility
- Maintain extra distance from the vehicle ahead
- Avoid driving if possible until conditions improve
"A dense fog advisory is issued by your local National Weather Service office when widespread dense fog develops and visibilities frequently drop to one-quarter of a mile or less," explains the NWS.
This advisory aims to alert residents and travelers to exercise caution due to the significantly reduced visibility caused by dense fog in the area.
Source: The National Weather Service
Publication Information
This story was originally published on November 7, 2025, at 1:52 AM.
Author's summary: The North Bay Interior Valleys face hazardous driving conditions due to dense fog reducing visibility to a quarter mile or less until 10 a.m.; drivers are urged to slow down and use caution.