, Issued at 1057 PM PDT Thu Sep 17 2026 (Today and Tonight)
Friday will be a transition day as the upper low from the last 24-36 hrs exits to the NE. During this transition we'll see some clouds again Friday morning, but not in the classic marine layer environment. More of a synoptically enhanced strato-cu set up with lingering lift from the departing low. Regardless of the reason, cloudy to start off the day with some patchy drizzle possible again. For what it's worth looking way north toward the OR coast a more marine layer stratus deck is solidifying as the subsidence inversion returns with building high pressure. I digress, the low exits today and shortwave ridging is to follow for Friday into Saturday. Shortwave ridging will kick off a brief warming and drying trend for the Bay Area and Central Coast. Max temps today will see a 5 to 15 degree jump from Thursday's readings. Not a bad way to begin the weekend with highs in the 60s and 70s coast and 70s to upper 80s inland. As high pressure builds in from the N and W and interior heats up we'll see an uptick in winds this afternoon. Strongest winds for the inland valleys and gaps/passes with gusts of 25-35 mph.
Friday will be interesting as the marine layer tries to reform with building high pressure, but a burst of offshore flow also develops over the higher terrain. Not strong by any means, but drying nonetheless. As such, think some stratus will develop along the coast and move inland. The real battle ground will be along the N Bay coast and N Bay Valleys where the offshore flow may win out.
..issued at 1145 PM PDT Thu Sep 17 2026 (Saturday through next Thursday)
The warm up from Friday continues into Saturday with another few degrees or warming. Warmest inland locations will reach the low 90s. Elsewhere lots of 70s and 80s - immediate coast 60s.
The rest of the long term is a little bit of a roller coast - sensible weather changes, but thankfully not major impactful changes. The shortwave ridge quickly gets replaced by a small fast moving upper level low. The biggest change from the passing upper low will be dropping daytime temps by up to 10 degrees. Monday will be another transition day as the upper low exits initiating a subtle warm up.
For the rest of next week had been rather uncertain with a variety of model solution. A slight trend in the longwave pattern was developing last night and tonight that trend continues. A very notable upper level trough/low develops near the Gulf of Alaska. Downstream of the feature a ridiculous ridge blankets the eastern half of the CONUS with very impressive heights nosing E Canada. This large area of high pressure also oozes westward, including some of CA. As a result, a warming trend kicks in just in time for the fall equinox. The peak of heat appears to happen Wednesday and Thursday. Current forecast has far interior locations reaching the mid to upper 90s with HeatRisk values reaching moderate. Stay tuned,
(12z TAFS) Issued at 429 AM PDT Fri Sep 18 2026
MVFR-IFR ceilings are coming into the region and forming along topographically favored hillsides, with further expansion expected through the next few hours. The cloud deck should retreat back to the coast through the post-sunrise hours, with gentle to moderate onshore winds expected in the afternoon and evening. The marine layer should redevelop through the day and allow for a more typical stratus pattern to develop overnight, although the ceilings and timing are low confidence. Opted to not take the most aggressive high resolution model output as gospel and kept most terminals in IFR conditions.
Vicinity of SFO, MVFR-IFR ceilings persist through around 18Z with a moderate west-northwest wind developing in the afternoon and evening hours. Stratus will return to the terminal region late tonight into Saturday morning, but confidence in the exact timing is low.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Confidence has decreased in widespread ceilings at the terminals as the leading edge of the cloud deck remains offshore, but patchy radiationally-driven clouds may cause IFR-LIFR ceilings at the terminals through the morning. Gentle to moderate northwest winds will develop in the afternoon and evening, with more widespread stratus coverage expected to develop in the early evening to the overnight hours.
(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.
