Issued at 905 AM PDT Fri Sep 11 2026
The rapid return of the marine layer yesterday evening has resulted in a marine layer depth of around 1600 feet per 12Z OAK Upper Air Sounding. As such, widespread cloud cover across the region with ceilings between 400-1100 feet. These clouds are forecast to quickly dissipate through late morning and hug the coastline by early afternoon. There is the potential for Monterey to only see brief periods of Sun today, if any at all. Temperatures are running 5-20 deg F (upwards of 30 deg F in the mid elevations) cooler than this time yesterday with afternoon maximum temperatures forecast to be near average along the coast and slightly above in the interior. That said, no updates are anticipated at this time as the current forecast remains on track.
RGass
, Issued at 1201 AM PDT Fri Sep 11 2026 (Today and tonight)
What a difference a day makes. The continuing development of a cutoff low off the coast of British Columbia has led to a remarkable cooling through the evening and overnight hours, the return of a marine layer of around 500-1000 feet, and a stratus deck over the coastal regions and through the Petaluma Gap and the Golden Gate. As of midnight, temperatures across the Bay Area and Central Coast are running around 5 to 25 degrees below what they were 24 hours prior. Through the day, the aforementioned cutoff low will strengthen as it parallels the coast of the Pacific Northwest. Morning lows will range from the middle 50s to lower 60s in the lower elevations, and the middle 60s to the middle 70s in the higher elevations, while afternoon highs will top out in the middle 80s to the lower 90s in the inland valleys, the upper 90s to the triple digits in the warmest spots of southern Monterey County, the upper 60s to the lower 80s close to the Bays, and the lower to middle 60s along the Pacific coast.
..issued at 1201 AM PDT Fri Sep 11 2026 (Saturday through Thursday)
The cooling trend continues into the weekend as the cutoff low moves into the Pacific Northwest, allowing for further development of the onshore flow and marine layer to take place. By the weekend, highs will drop into the middle 70s to middle 80s inland and the upper 60s to upper 70s close to the Bays. Breezy onshore winds are expected through the weekend as the passing cutoff low tightens the pressure gradient over the northern half of California. Regarding the SFO-WMC gradient, model output has kept the peak gradient somewhere in the 10 to 15 mb range late on Saturday, with widespread gusts of 25 to 35 mph possible Saturday evening into Sunday morning. Favored gaps, passes, and coastal regions could see gusts to 45 mph.
The trough axis should move into the northern Rockies and the northern Plains for the early part of next week, but the general pattern should remain rather zonal for the remainder of the 7-day outlook, and temperatures should remain more or less stable with highs near or slightly below seasonal averages.
(18z TAFS) Issued at 1030 AM PDT Fri Sep 11 2026
Stratus coverage is decreasing across the Bay Area but persists directly along the coast and along the Monterey Peninsula. Cloud cover is expected to continue decreasing through the remainder of the morning with low to moderate confidence in the timing of stratus return tonight. HREF keeps stratus more confined to the coast and along the SF Bay shoreline with the marine layer ~1000 ft. The marine layer did overperform this morning (12Z OAK sounding reported it to a depth of 1500 ft) which resulted in more widespread cloud cover. If the marine layer again overperforms tonight then we may see more expansive cloud cover than currently forecast. Generally expecting IFR to LIFR CIGs with lower CIGs expected along the coast. Gusty onshore winds return this afternoon with winds decreasing overnight. There is an early signal for gusts between 25 to 30 knots on Saturday so have started including after 18Z Saturday for 30 hour TAF sites.
Vicinity of SFO, VFR persists through tonight with a low to moderate chance for stratus to impact the airport overnight. Confidence is low that stratus will reach SFO as the latest guidance keeps stratus more confined to the coast and mainly impacting OAK in the SF Bay. If stratus does reach SFO it will likely be early Saturday morning and clear by noon at the latest. Strong onshore winds are expected Saturday afternoon/evening with gusts to around 30 knots, potentially up to 35 knots, likely.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Stratus has cleared at SNS but is persisting over MRY. Guidance shows some potential for stratus to persist at MRY through the day but there may be a brief period of clearing/VFR conditions this afternoon. IFR-LIFR stratus returns overnight and persists through the end of the TAF period. Breezy onshore winds return during the day before decreasing overnight.
(today through Wednesday) Issued at 905 AM PDT Fri Sep 11 2026
A moderate to fresh NW breeze will increase over the next 24 hours, with a strong breeze to develop by early Sunday and continue into next week. Near gale force to gale force winds are expected along the inner waters from Pigeon Point to Point Piedras Blancas, the Monterey Bay, and in portions of the San Francisco and San Pablo Bays. Hazardous conditions for small craft will prevail late this weekend through mid next week. Seas are currently moderate and will build to rough by Monday in response to the stronger winds.
Ca, None. PZ, Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm- SF Bay N of Bay Bridge.
Small Craft Advisory until 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM.
