The National Weather Service in San Francisco has issued a Dense Fog Advisory for the North Bay and East Bay Interior Valleys, which is scheduled to remain in effect until 11:00 AM today. Travelers wading through these areas are advised to reduce their speed, allocate additional arrival time, maintain increased vehicle spacing, and, crucially, refrain from using high-beam headlights in the soupy conditions. The advisory, as published on the NWS website, is designed to ensure the safety of motorists in the affected regions.
The weather forecast indicates that, following the dissipation of the morning fog, residents can expect a return to sunny skies and mild weather conditions, which are consistently 5–10 degrees above normal for interior locations. These conditions are anticipated to persist through Thursday, contributing to an ideal Thanksgiving Day ambiance. According to their Area Forecast Discussion, "A progressive, upper level disturbance well to our north takes aim at the Pacific Northwest Thursday night into Friday." However, the same disturbance is likely to bring cooler temperatures heading into the weekend.
From an aviation standpoint, the fog has led to Lower Instrument Flight Rules (LIFR) and Very Low Instrument Flight Rules (VLIFR) conditions across the North and East Bay valleys. The high cloud cover has reportedly made it challenging to determine the extent of the stratus layer, significantly impacting visibility. While gusty offshore winds have improved conditions at certain terminals, uncertainty remains regarding the development of stratus for the rest of the morning, with notable surveillance warranted at Oakland (OAK), San Jose (SJC), and Salinas (SNS) airports.
Marine activities haven't been spared, with dense fog creating treacherous conditions along the West Delta and San Pablo Bay. Mariners are advised to proceed with caution until the advisory expires late this morning. The NWS's marine forecast indicates that gentle to moderate northerly conditions will prevail through midweek. However, winds and, consequently, seas are expected to gain momentum again towards the end of the week, fostering moderately rough sea states.
