Overview
- National Weather Service dense fog advisories on Wednesday morning covered much of the San Joaquin Valley, warning of visibility a quarter mile or less through late morning.
- A roughly 400-mile fog bank from Bakersfield past Sacramento has re-formed nightly and has extended into some Bay Area valleys.
- Forecasters expect conditions to rebuild overnight to Level 3 on the five-tier index, indicating moderate risk and visibility around half a mile.
- Officials urged drivers to avoid travel on I-5, SR-99, SR-152 and SR-198, use low-beam headlights, leave extra distance, and watch for CHP pace vehicles.
- The stagnant layer has degraded air quality, prompting Spare the Air alerts, even as orchards gain valuable winter chill hours.