, 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.
(18z TAFS) Issued at 1100 AM PDT Fri Sep 18 2026
Lingering low clouds and fog has dissipated from most of the interior valleys and Central Coast but NW winds still feeding a fresh batch of stratus over SF Bay. Most terminals VFR the rest of today into early evening except for SFO/OAK and HAF. Marine layer compressing with onshore winds so stratus should push inland early this evening.
Vicinity of SFO, Stubborn broken deck still occurring over SFO and satellite trends indicate upstream stratus still spreading inland. For now tafs will keep 21z for clearing time. Confidence low overall given atypical synoptic pattern. Once clearing occurs expect low clouds to spread back over the terminal around 08-09z tonight.
SFO Bridge Approach, Clear skies reported over bridge approach and that should last through at least 03-05z this evening.
Monterey Bay Terminals, Low clouds have cleared for this morning. Expect an early return for KMRY, around 02z forecast at this time with low cigs spreading down the Salinas valley overnight. Shallow marine layer depth on Saturday suggests clearing by around 18z.
(today through Wednesday) Issued at 429 AM PDT Fri Sep 18 2026
Gentle west to northwest breezes become moderate to fresh by the afternoon into 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 this morning through Saturday. Winds gradually diminish across the southern coastal waters by Saturday evening, but remain elevated across the north. Slight to moderate wind driven seas persist through the weekend and steadily build to rough by early next week.
Ca, None. PZ, Small Craft Advisory from 3 PM this afternoon to 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 from 3 PM this afternoon to 3 AM PDT Sunday for Pt Arena to Pt Reyes 0-10 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.
Small Craft Advisory from 9 PM this evening to 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10- 60 NM.
