Issued at 658 PM PDT Fri May 22 2026
Coastal stratus is beginning to flow into the inland regions this evening, particularly through the Petaluma Gap, Golden Gate, and across the Monterey Bay region. The latest readings from the Bodega Bay profiler suggest that the marine layer has further thickened to around 2000 feet. If this holds overnight, the higher elevations and perhaps the very eastern sections of Contra Costa County will be the only regions to escape stratus cover tonight.
DialH
, Issued at 1250 PM PDT Fri May 22 2026 (This evening through Saturday)
The marine layer deepen to ~1500 ft this morning and resulted in cooler conditions along the coast and adjacent valleys. May not have lowered temperature in these areas enough, however they are on a warming trend now the Sun is out. Thus, expecting afternoon temperatures to warm into the upper 70s to middle 80s across the interior, lower 60s to lower 70s around the San Francisco bayshore, and upper 50s to middle 60s near the coast. Dry conditions persist this afternoon with elevations above 1500 ft are seeing 10%-30% humidity values.
As the marine layer is forecast to remain steady, low clouds near the coast will spread further inland this evening and spread deeper into the valleys early Saturday morning. There is also the potential for coastal drizzle, yet the probability is not great enough to include in the official forecast grids.
For Saturday afternoon, we are expecting slightly cooler temperatures than today as stratus will be slower to clear. This is also in response to more zonal for developing over the region.
..issued at 1250 PM PDT Fri May 22 2026 (Saturday night through next Thursday)
Zonal flow will persist on Sunday, thus temperatures will be similar to those on Saturday as far as afternoon maximum temperatures go. During the late evening and overnight hours, cannot rule out coastal drizzle again Saturday night into Sunday morning.
By late Monday and early Tuesday, a cold front associated with a deep upper level through is forecast to sweep across the region. This would result in drizzle and/or light rain as the front moves from north to south across the Bay Area and Central Coast. However, widespread rainfall is not expected and will be very light not amounting to much more than a few hundredths of an inch. In wake of the frontal passage, the marine layer may mix out and allow for coastal locations slightly warmer compared to this weekend. Winds are also forecast to strengthen over the coastal waters on Tuesday and Wednesday.
From the previous forecaster: "Towards the later part of the week, the ensemble model runs begin to diverge as the evolution of the upper level low and incoming ridging becomes uncertain. Most runs lean towards a warming trend for that period, which is reflected in the current forecast, with a significant minority (around 30-40% of the runs) suggesting that some form of trough lingers through the period."
(06z TAFS) Issued at 901 PM PDT Fri May 22 2026
The stratus deck has begun its push onshore and is set to impact all terminals at some point (except for SJC and LVK) during the TAF period as the marine layer continues to deepen. Winds reduce through the night, thus allowing MVFR-IFR ceilings to develop. By Saturday late morning, winds will locally increase which will help to mix out the remaining low stratus in the area, confining the deck right off the coastline while still impacting HAF.
Vicinity of SFO, MVFR ceilings will develop around 09Z Saturday (though they may arrive a couple hours early) as the stratus intrusion continues onshore and marine layer deepens. The low ceilings begin to mix out late Saturday morning as moderate winds develop through the afternoon, shifting back to VFR through the TAF period with the potential for another round of MVFR ceilings Saturday night.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, As winds diminish overnight, MVFR-IFR ceilings will prevail into late Saturday morning with slight impacts to visibility. Winds will increase Saturday morning which will mix out the stratus deck and push it offshore, shifting to VFR conditions for a short period. The marine layer is expected to push back onshore Saturday evening for another round of MVFR-IFR ceilings.
(tonight through next Thursday) Issued at 901 PM PDT Fri May 22 2026
Moderate to strong northerly breezes prevail in the northern outer waters allowing rough seas to build in the surrounding area. Conditions remain hazardous for small crafts in the aforementioned area through Saturday morning. Elsewhere, west to southwesterly winds will remain light to gentle with moderate wave heights. Seas begin to gradually abate to moderate heights by midday Saturday through early Tuesday morning. An incoming trough is set to approach our waters late Monday night, bringing strong northwesterly winds and building rough seas.
Ca, None. PZ, Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM.
