Issued at 908 PM PDT Fri Sep 18 2026
Satellite imagery shows stratus clouds returning to the coastal regions from Bodega Bay down to Davenport and again from the Elkhorn Slough to Point Sur. There is also stratus flow into the East Bay west of the Berkeley-San Leandro Hills and through the Petaluma Gap. Latest observations suggest that the marine layer is beginning to redevelop at around 1000-1500 feet, allowing stratus to come rather far inland tonight.
DialH
, Issued at 1120 AM PDT Fri Sep 18 2026 (This afternoon through Saturday)
The marine layer compressed to around 1,700 feet this morning. That trend will continue over the next 24 hours as a short wave ridge builds over the area. While the W-E gradients are all still weakly positive (SFO-WMC +1.9mb, SFO-SAC +1.2mb) we did see some NE, offshore winds this morning. The gradients will continue to drop and become negative this afternoon, however the onshore sea breeze will overpower any offshore flow during the day.
In response to the building ridge and compressed marine layer, Inland temperatures will be roughly 5 degrees warmer today compared to yesterday, and another 5 degrees warmer Saturday. While less expansive, the marine layer will continue to keep high temps along the coast in the 60s with low clouds and possible fog in the morning. The offshore wind gradient will peak overnight, though the strength still isn't overly impressive. Still, NE winds with gusts up to 20-30 mph are possible across the interior North Bay Mountains late tonight and early Saturday morning.
..issued at 1120 AM PDT Fri Sep 18 2026 (Saturday night through next Thursday)
The pattern remains quite active in the long term forecast, although the next few features are pretty weak. Saturday's ridge is quickly replaced by a weak cut-off low approaching from the west through the day Sunday. This will reverse the warming trend and allow the marine layer to expand a bit. This low will gradually slide overhead by Monday morning, giving us a good chance for drizzle.
By Tuesday another ridge will start to build from the west, kicking off a warming trend that will last through the rest of the week. The ECMWF ensemble shows a 90% chance that the 850 mb temperature gets above 20C on Wednesday with a mean around 23C. 23C is above the the 90th percentile for this time of year and would bring inland surface temperatures back into the 90s.
(00z TAFS) Issued at 421 PM PDT Fri Sep 18 2026
Some MVFR ceilings linger at the immediate coast but most of the region enjoys VFR ceilings and a gentle to moderate onshore wind through the evening hours. A compressing marine layer should keep stratus within the inland valleys through the night with generally low-end MVFR-LIFR ceilings expected. Stratus will retreat to the immediate coast through Saturday morning with onshore winds resuming in the afternoon, expected to be weaker than today's winds.
Vicinity of SFO, VFR through the late evening and early overnight hours with strong northwest winds gradually diminishing in the evening hours. MVFR-IFR stratus comes into the terminal area around 06-08Z with the stratus deck expected to set up just to the north of the terminal before expanding southwards. Stratus mixes out Saturday morning with breezy northwest winds resuming in the afternoon, with clouds returning in the evening hours.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR conditions expected to continue for the next couple hours near MRY and into the evening at SNS, with a moderate northwest to west breeze expected into the evening hours. IFR ceilings will develop this evening and overnight as the winds become light, with some potential for LIFR ceilings at MRY. Stratus retreats to the immediate coast Saturday morning with breezy winds resuming in the afternoon.
(tonight through next Thursday) Issued at 908 PM PDT Fri Sep 18 2026
Moderate to fresh northwest winds persist through the weekend. Strong gusts up to 30 kt are possible across the northern coastal waters, Big Sur coastal jet region, and the Monterey Bay region through Saturday. Winds briefly diminish across the southern coastal waters Saturday morning, but increase again to fresh by Saturday afternoon. Slight to moderate wind driven seas prevail this weekend and steadily build to rough early next week.
Ca, None. PZ, Small Craft Advisory until 3 AM PDT Saturday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 3 PM Saturday to 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
