Issued at 643 PM PDT Thu May 21 2026
Stratus continues to impact the immediate coast with some inland expansion across the Monterey Bay region, and a finger of stratus coming through the Golden Gate into the Berkeley area. The Bodega Bay profiler is reporting a marine layer depth of around 1000 to 1500 ft, which is conducive to expanded stratus development into the inland valleys through the early hours of Friday morning.
DialH
, Issued at 1234 PM PDT Thu May 21 2026 (This evening through Friday)
Today we continue to see dry conditions across the interior and with afternoon maximum temperatures reaching the lower 80s to lower 90s under sunny skies. Meanwhile, the coast will stay cooler thanks the ~1000 ft marine layer where we are expecting the upper 50s to middle 60s. With the large scale pattern aloft is defined by a through over the northern Rocky Mountains and a building ridge over the northeastern Pacific. This pattern largely supports onshore winds at the surface with coastal breezes developing each afternoon and evening.
Tonight, expect the marine layer to remain steady, yet the inland extent is likely to increase into the coastal adjacent valleys early Friday morning. However, similar to today, these low clouds will quickly retreat to the coastline by late morning.
Friday we are expecting a slight cool down in afternoon temperatures as the trough shifts eastward allowing for a deeper marine layer to return. Coastal areas are likely to remain in the upper 50s to middle 60s with the interior warming into the upper 70s to middle 80s. The only far interior areas like Pinnacles National Park, King City, San Lucas, and San Ardo have the potential to reach 90 deg F.
..issued at 1234 PM PDT Thu May 21 2026 (Friday night through next Wednesday)
The cooling trend will continue into this upcoming weekend with temperatures returning to near seasonal averages. This is as the marine layer is forecast to deepen to ~1500 ft. Cannot rule out late evening and early morning coastal drizzle during this timeframe as the boundary layer remains very moist.
By late Monday and early Tuesday, a frontal boundary is forecast to sweep across the region. This would bring the potential for drizzle and/or light rain as the front moves from north to south across the Bay Area and Central Coast. In wake of the frontal passage, the marine layer may mix out and allow for coastal locations slightly warmer compared to this weekend.
(06z TAFS) Issued at 938 PM PDT Thu May 21 2026
Currently a mixed bag of LIFR-VFR at the terminals. Moderate to high confidence on IFR-LIFR conditions returning to all the terminals tonight with the exception of the interior terminals of LVK and SJC. Diurnal winds will prevail.
Vicinity of SFO, Currently VFR with northwesterly flow. Stratus is currently being held off just to the northwest of the terminal. Moderate confidence on this reaching the terminal, likely around 09Z. Diurnal winds will prevail.
SFO Bridge Approach, Low clouds coming in through the Golden Gate Gap will continue to spread south along the East Bay Shoreline tonight with the San Mateo Bridge Approach likely to be impacted through late morning.
Monterey Bay Terminals, Currently IFR with southwesterly flow at MRY and IFR with northwesterly flow at SNS. High confidence on conditions deteriorating to LIFR with fog possible. VFR is expected by late morning with IFR stratus sticking close to the coast during the day. Another early return of stratus is expected tomorrow night.
(tonight through next Wednesday) Issued at 938 PM PDT Thu May 21 2026
Hazardous conditions for small craft continue tonight for the northern outer waters due to strong northerly breezes and rough seas. Moderate northwesterly breezes will back to become southwesterly tomorrow and prevail through the weekend. Rough waters are expected across the northern outer waters Friday with widespread moderate seas prevailing Saturday through Monday.
Ca, None. PZ, Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt Reyes 10-60 NM.
