075 FXUS66 KMTR 041103 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 303 AM PST Tue Nov 4 2025 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 257 AM PST Tue Nov 4 2025 - Wind gusts of 45 to 65 mph are forecast for portions of the North Bay, East Bay, SF Bay, and Santa Cruz Mountains. - Low potential for nuisance flooding in the North Bay, but moderate rainfall will be largely beneficial. - Thunderstorm chances remain around 10 to 20 percent with the main hazards being pockets of heavier rainfall and enhanced outflow winds. && .SHORT TERM... Issued at 257 AM PST Tue Nov 4 2025 (Today and Tonight) Quiet weather to start the day today will transition to more turbulent conditions tonight and into the day on Wednesday. High clouds continue to filter in overhead across the North Bay and this should curtail the threat for widespread dense fog (and perhaps fog in general). Farther south, the lack of mid and upper level clouds has facilitated more in the way of radiative cooling and we're starting to see some sites dip down to 1/2 mile. Trends will be monitored this morning for a short-fused Dense Fog Advisory (would be the SC Mountains and Salinas Valley). Fog should mix out rapidly by mid to late morning. Our well advertised upper low will inch toward Northern California through the day. As it does, it'll induce pressure falls and tighten the surface pressure/height gradient. In response, southerly winds will ramp up, especially after 00Z across marine zones and adjacent coastal regions. Across the southern Big Sur Coast, there will likely be sufficient ascent for some WAA convection and after discussion with LOX, opted to add in some showers. The largest impact with this system is anticipated to be the wind. The general timeline for winds will be from roughly 10pm tonight through 4pm Wednesday. Over the last few days, model guidance has come into greater agreement with regard to placement of the greatest corridor of winds will reside. Just about all deterministic guidance indicates that a belt of 50 to 60 knot flow will nose in from the southwest across the Sonoma and Marin Coastline. At the surface, our trusty MTRWRF and PG&E/SJSU WRFs support surface wind gusts in excess of 60 mph for the Pacific Coast north of the Golden Gate strait and I've upgraded this region to a High Wind Warning for wind gusts of 60 to 65 mph which aligns with the corridor of high 925mb winds. Taking an examination at some the Extreme Forecast Index tools, there's a very strong signal that the EPS ensemble forecast distribution is substantially higher than the model's climatology. In fact there's some indication that a few of the EPS ensemble members are quite anomalous/extreme. What this translates to is a potential for 65-70mph wind gusts in spots. Areas south of the Golden Gate are on the fringes of the aforementioned 925mb jet max, but wind gusts in the 45 to 55 mph (and thus a Wind Advisory) are advertised for SF, the San Mateo Peninsula, East Bay, and Santa Cruz Mountains, though it's not out of the realm of possibility that some of these areas may need to be added to the High Wind Warning, especially if the corridor of strongest winds shifts southward. Regardless of High Wind Warning or Wind Advisory, individuals should secure any loose outdoor articles/decor and anticipate driving difficulty for high-profile and lightweight vehicles (especially on east-west oriented roadways). In addition, there will be the potential for sporadic power outages, particularly across the Pacific Coast near/north of the Golden Gate. && .LONG TERM... Issued at 257 AM PST Tue Nov 4 2025 (Wednesday through Monday) Potentially enhancing winds via precipitation loading will be pockets of moderate to at times heavy rainfall. This will be most probable across the North Bay where instability is forecast to be the greatest. In fact, forecast soundings and hi-res NWP indicate meager, but sufficient amounts of MUCAPE of around 100-250 J/kg across the North Bay and the thunder potential is largely confined to this region and adjacent waters. The main hazard with storms will be bursts of stronger winds and heavier precipitation. While heavy rainfall is possible, the potential for widespread flooding appears to be on the low side for a couple of reasons. 1) Near surface soil moistures are running near or below normal per NASA SPoRT output, and 2) the progressive nature of this system should minimize the potential for training thunderstorms. Examination of experimental flood mapping as well as the Hydrologic Forecast Ensemble System indicates little to no responses across the main stem rivers. That said, some of the more heftier precipitation rates will transpire during the Wednesday morning commute and this may result in traffic impacts as water mixes with oils in roadways and ponding/nuisance flooding takes place in urban/poor drainage areas. Again, the system appears that it'll remain progressive and we don't anticipate a high potential for stalling/training of precipitation bands. Overall rainfall amounts remain somewhat consistent with previous forecast iterations, though there have been some adjustments upward in the higher terrain/favored coastal regions. North Bay rain amounts appear that they'll still average anywhere between 0.50" in the 'rain shadowed' areas to the 1-2.5" range across the higher terrain. Some of the more prominent North Bay Mountains may be the recipients of more optimal upslope flow with values just under 3". We'll need to potentially make some last minute refinements to QPF as there are some meaningful probabilities of over 3" amounts across coastal Sonoma County between Sea Ranch and Bodega Bay. Farther south, rain amounts average between 0.25" to 0.75" across the Bay Area and Central Coast, with amounts over 1" across the Santa Cruz Mountains, Santa Lucia Range, and Big Sur Coast. Precipitation is anticipated to taper off through Wednesday night. Rapid clearing in the wake of the precipitation and diminishing winds may set the stage for a decent radiation fog event, especially across the North Bay where the heaviest rainfall is anticipated. However, this may be modulated by lingering cloud cover, wind speeds and/or the amount of dry air that filters in behind a front. The weather pattern appears that it'll remain progressive with largely zonal flow anticipated as we round out the first full week of November. There are some hints at a few perturbations rippling through the flow that may give the North Bay a few opportunities for additional light rainfall. && .AVIATION... (06Z TAFS) Issued at 921 PM PST Mon Nov 3 2025 IFR-LIFR stratus developing across the Monterey Bay region and lingering along the coast south of Point Sur, with mid-to high level clouds streaming in through the Bay Area and points north. The interaction between the coastal stratus and the higher prefrontal clouds is a complex interaction as the high clouds could interfere with the radiational cooling that would contribute to fog or low stratus, decreasing the confidence in the forecast for stratus formation tonight and dissipation on Tuesday morning. Current best forecast is for the stratus to expand into the coastal valleys through the night and retreat to the coastal regions through the morning. Southerly winds will increase through Tuesday with the strongest winds developing near or slightly beyond the end of the 24- hour TAF period. Scattered showers will develop in the North Bay Tuesday night but the main rain band likewise arrives after the end of the TAF period. Vicinity of SFO... VFR at present. Coastal stratus and prefrontal clouds combine to give the terminal a moderate confidence for MVFR ceilings in the early part of Tuesday morning, dissipating after sunrise. The winds will shift to a more south-southwest flow on Tuesday in advance of the front, which continue to increase through and beyond the end of the TAF period. Some high resolution models depict chances for MVFR ceilings during the Tuesday evening timeframe, but confidence is too low to include in the TAF. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals... IFR-LIFR stratus is developing, currently impacting SNS and will come over MRY sometime tonight. Local effects will influence the time of stratus development so the TAF ceiling forecast is a moderate confidence forecast. Strong southwest winds will develop at MRY Tuesday afternoon, while confidence is moderate that winds at SNS develop from the northwest. Winds diminish Tuesday evening with moderate confidence of radiative fog at MRY that night. && .MARINE... (Tonight through next Sunday) Issued at 921 PM PST Mon Nov 3 2025 Moderate breezes across the waters will continue through the night before increasing on Tuesday, with winds across the waters to the north of Point Pinos already coming from the south and those to the south gradually shifting to the south through the night. By late Tuesday and into Wednesday, near- gale force to gale force sustained winds are expected. Widespread gale force gusts are expected during this time with isolated storm force gusts possible for the northern most waters. Seas will build to become very rough for the inner waters and outer waters Wednesday and Thursday. Rain showers Tuesday will turn into widespread rainfall and a slight chance for thunderstorms Wednesday. && .BEACHES... Issued at 402 AM PST Mon Nov 3 2025 A long period northwesterly swell will continue to bring an increased risk for sneaker waves, rip currents, and breaking waves of up to 20 feet to Pacific Coast beaches today. High surf conditions are possible, especially at the west and northwest facing beaches. Remember, sneaker waves can unexpectedly run significantly farther up the beach than normal, including over rocks and jetties. Rip currents are typically more frequent and stronger in the vicinity of jetties, inlets, and piers. Swimmers should always swim near a lifeguard. Stay off the rocks, remain out of the water to avoid hazardous swimming conditions, and never turn your back on the ocean! && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement until 3 AM PST early this morning for CAZ006-505-509-529-530. Coastal Flood Advisory from 8 AM this morning to 2 PM PST Saturday for CAZ006-506-508-529-530. Wind Advisory from 10 PM this evening to 4 PM PST Wednesday for CAZ006-503-504-506-508>510-512-515. High Wind Warning from 10 PM this evening to 4 PM PST Wednesday for CAZ502-505. PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PST this evening for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge. Gale Watch from this evening through Wednesday afternoon for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge. Small Craft Advisory from 9 PM this evening to 3 PM PST Wednesday for Mry Bay. Small Craft Advisory from 9 AM this morning to 9 PM PST this evening for Pt Arena to Pt Reyes 0-10 nm. Gale Watch from this evening through Wednesday morning 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 until 9 PM PST this evening for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Bain LONG TERM....Bain AVIATION...DialH MARINE...DialH Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea