, Issued at 1202 AM PDT Sat Sep 19 2026 (Today and tonight)
Marine layer stratus has developed along the coast and is flowing into the SF Bay Area and Monterey Bay regions. Some patches of radiational stratus have also developed inland. Further expansion is expected across most of the valleys tonight before stratus retreats to the immediate coast after sunrise.
The weather pattern places an upper level ridge over the West Coast today, allowing for the warming trend over the last couple of days to continue. The upper level trough that brought us cool temperatures and widespread clouds is crawling over southern Idaho, and as it does, the pressure gradients will start to support some northeasterly offshore flow in the higher elevations of the North Bay and East Bay, with gusts to 20 to 30 mph possible through the morning hours. At midnight, the SFO-WMC gradient has turned negative at -1.3 mb, and will peak around -2 or -3 mb during the 6-9 AM timeframe. High temperatures in the inland valleys will reach the 80s to the lower 90s, while the Bays reach the upper 60s to the lower 80s and the Pacific coast hovers in the lower to middle 60s. Afternoon breezes should be similar to those seen yesterday with gusts of 20 to 30 miles per hour along the coast, through favored gaps and passes, and within the Salinas Valley.
..issued at 1202 AM PDT Sat Sep 19 2026 (Sunday through Friday)
On Sunday, a cutoff low heads into the state and interrupts the warming trend, cooling the inland valleys by around 5 to 10 degrees for Sunday and Monday such that highs will be in the middle 70s to the lower 80s, rising to the middle 80s up to the lower 90s in the interior parts of the North Bay and Central Coast, with the Bays see highs in the middle 60s to the middle 70s. By Monday morning, the core of the low should set up right over the Central Coast, giving us a slight chance for drizzle.
Upper level ridging returns by Tuesday, and a warming trend resumes with the current forecast showing Moderate HeatRisk returning to a fair swath of the interior by Wednesday and Thursday, most notably the interior East and South Bays and the Santa Lucia range. This would correspond to a moderate risk for heat related illnesses within sensitive populations (children, the elderly, pregnant women, people with chronic diseases, and people who work or live outdoors without adequate cooling or hydration). Inland highs for Wednesday and Thursday are expected to be in the 90s, which is supported by ensemble models continuing to show that 850 mb temperatures above 20C (or temperatures around 1500 ft above sea level above 68F) are likely to nearly certain for those two days, with an average around 21-22C, close to the 90th percentile for this time of year. This is a shade cooler than the last forecast update, so we will be watching how the situation evolves as we go through the weekend.
(12z TAFS) Issued at 418 AM PDT Sat Sep 19 2026
IFR and low-end MVFR stratus are developing across the inland valleys with some further expansion possible before sunrise. Stratus will retreat back to the coastal regions through the morning with a gentle to moderate onshore flow through the afternoon and evening hours. Stratus returns to the terminals this evening and overnight, with moderate confidence on timing and ceilings heights.
Vicinity of SFO, IFR to low-end MVFR stratus persists through around 18Z with moderate to strong northwest winds developing in the afternoon and evening hours. MVFR-IFR stratus returns in the evening as the winds turn light, with clearing not expected through late SUnday morning close to the end of the TAF period.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, IFR-LIFR ceilings persist through the late morning hours around 18Z. Gentle to moderate northwest winds develop in the afternoon and evening hours, with IFR-LIFR ceilings returning in the evening, although confidence in stratus development time is moderate.
(today through Thursday) Issued at 418 AM PDT Sat Sep 19 2026
Moderate to fresh northwest winds persist through the weekend. Strong gusts up to 30 kt are possible across the northern coastal waters, the Big Sur coastal jet region, and Monterey Bay through the day. Winds briefly diminish across the southern coastal waters this morning, but increase again to fresh by the 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 9 AM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM.
