131 FXUS66 KMTR 282141 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 141 PM PST Sat Feb 28 2026 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 135 PM PST Sat Feb 28 2026 - Cooler Sunday with very light rain across the North Bay and Pacific Coast - Above normal temperatures with elevated winds and offshore flow next week - Potentially hazardous marine conditions next week && .SHORT TERM 135 PM PST Sat Feb 28 2026 (This evening through Sunday) Another pleasant day is in progress across the Bay Area and Central Coast. Mostly sunny skies, outside of some building mid/upper level clouds, has translated to temperatures largely in the 60s to near 80 degrees. While weaker offshore flow has resulted in 24 hour temperature departures are running 5 to 10 degrees lower at the coast. Cloud cover has hampered some warming across the North Bay. Mostly sunny skies across East Bay, South Bay, and Salinas Valley regions have allowed +7 to +10 degree 24 hour temperature departures. By mid to late afternoon, the sea- breeze should kick in and knock temperatures down a a few degrees. Winds may elevate briefly as well, with gusts in the 15 to 25 mph range for 1 to maybe 2 hours. Thereafter, winds will abate with gusts below 15 mph. Our initial wave that resulted in thunderstorm activity across our outer marine zones will continue to lift northward. In its' wake, a secondary upper trough/low will swing eastward. Mid-level height falls and large scale ascent should promote largely shower type activity Sunday afternoon and evening. && .LONG TERM... Issued at 135 PM PST Sat Feb 28 2026 (Sunday night through next Friday) MUCAPE needed for lightning appears that it'll remain confined to extreme northern parts of the East Bay and a 20% chance for thunderstorms seems reasonable. While PoPs average between 40%-60%, rain amounts are anticipated to remain largely under one- tenth of an inch. Higher end amounts suggest that areas that would approach one-tenth of an inch (or greater) are most probable across the North Bay terrain (namely Coastal Ranges/Hills). PoPs, while probably a little broad-brushed, extend as far south as the Big Sur Coastline where RRFS output suggest the potential for a few showers. Onshore flow should encourage orographic ascent across the coastal ranges and there will be a potential for drizzle along the Pacific Coast (and across some of the higher terrain in the East Bay). Rain chances fall down to near zero Monday afternoon with a predominately rain-free forecast (outside of the mid-week time frame). On Wednesday, an amplifying trough with an attendant front will slice through the area. The latest guidance does paint a 20-30 PoP across the North Bay, however, there does remain some spread in this portion of the forecast. Taking a look at the multi-model ensemble clusters reveals that 75% of the guidance offers a more northern track to this upper trough which would mean a lower chance for rain across the North Bay. However, the remaining quarter of the multi-model ensemble (including the deterministic ECMWF) does offer a more southern trek for the mid- week system. This would equate to a larger PoP footprint as far south as the Golden Gate strait. For now, NBM PoPs seem reasonable and I didn't make any deviations here and rain chances are limited to the North Bay during this time. QPF during the mid- week system is also anticipated to be predominately a few hundredths of an inch. The primary weather headline in the long term will be the potential for increased northerly winds, particularly across the higher terrain as well as across the marine environment. Overall, the blended guidance seems to offer a reasonable wind gusts forecast given where it is (over 72 hours out). As surface pressures rise in the wake of the aforementioned trough/front, the MSLP gradient between building high pressure and the surface coastal trough will tighten. This is a common pattern that result in winds overachieving, particularly across the complex terrain. As a result, wind gusts across the mountain zones have been adjusted upward closer to the higher end of the NBM envelope. It should be noted, the position of the trough as discussed earlier, will modulate just exactly how the winds manifest themselves across the higher terrain. As noted before, any fire ignitions may pose some growth potential in dead/dormant vegetation. The marine environment, however, seems more likely to experience wind gusts in excess of 30-35 knots. Similar to PoPs, the blended guidance may have a broader than reality wind field, but hazardous marine conditions do appear that they'll transpire. For more details, see the marine section below. && .AVIATION... (18Z TAFS) Issued at 1024 AM PST Sat Feb 28 2026 Our first upper trough continues to lift northward and a secondary upper air disturbance will encourage stronger onshore flow as well as an increase in moisture. VFR ceilings will become MVFR and even a window for IFR, especially at North Bay Terminals. The onset time is tricky and current thinking is that MVFR/IFR will be more probable closer to 12Z Sunday. However, if the secondary upper low moves more quickly to the east, sub-VFR cigs as early as 06Z are more likely. IFR/LIFR is most likely at KSTS and KHAF through the end of the valid TAF cycle, though if the marine layer deepens, cigs may lift quickly, with a non-zero chance that VFR returns prior to 18Z Sunday. Confidence in the cig forecast is greatest in the North Bay, with lesser confidence farther south, where terrain may hinder the advancement of stratus at some locales (e.g., LVK and SJC). Largely terrain driven flow this afternoon and tonight will become more westerly with the approach of the upper low. Vicinity of SFO...Currently VFR with NE'ly winds. The delayed sea-breeze push is expected closer to 21Z. While confidence has diminished in IFR, forecast soundings/cross-sections do indicate that the initial push of moisture may be low enough such that cigs are below FL010, at least for a few hours around 12Z Sunday. The Sunday AM push is likely to be impacted due to IFR/MVFR. As onshore flow continues, cigs will lift, becoming VFR during the afternoon. If moisture is deeper than anticipated, MVFR may persist longer than advertised. At this time, the potential for SHRA INVOF appears that it'll be after 00Z Monday, but if the upper trough accelerates faster, adjustments to include precip in the 24-30 hour window of the TAF will be needed. SFO Bridge Approach...Cigs are likely to arrive up to 2 hours after the initial arrival at the terminal. Monterey Bay Terminals...VFR conditions with a persistent push of onshore flow is expected through tonight. Moderate confidence that our stratus deck will push through around 10-11Z Sunday resulting in IFR conditions. Once it comes through, it is expected to remain IFR through 18Z Sunday at KMRY and potentially closer to 16Z at KSNS. The onshore winds are forecast to be light, largely within the 6 to 8 knot range, with gusts up to 10 knots. && .MARINE... (Today through Thursday) Issued at 856 AM PST Sat Feb 28 2026 Average to long northwesterly swell will continue through the weekend before wave heights and swell periods both decrease. Rougher seas should be anticipated in and around shower or thunderstorm activity. The risk for this activity will continue through Sunday. Seas continue to abate until about mid-week. Thereafter, conditions will deteriorate as a series of stout strong systems usher in Gale Force wind gusts and steep seas over 12 feet. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...Bain LONG TERM....Bain AVIATION...Bain/AN MARINE...Bain 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