FXUS66 KMTR 020958 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 158 AM PST Fri Jan 2 2026 ...New SHORT TERM, LONG TERM, BEACHES... .KEY MESSAGES... Updated at 1236 AM PST Fri Jan 2 2026 - High astronomical tides combined with storm surge will bring substantial tidal flooding through Sunday - Strong southerly winds Friday night into Saturday morning - Chance of thunderstorms Friday night through the weekend - Daily rain showers expected through Monday && .SHORT TERM... Issued at 1236 AM PST Fri Jan 2 2026 (Today and tonight) There's a few scattered showers on radar, but we're mostly enjoying a break before the next round of heavy rain and strong wind arrives tonight. Southerly winds are starting to show up along the coast and in properly oriented valleys. Salinas and Half Moon Bay are both reporting a moderate southerly breeze with gusts up to 20 knots. The IR satellite image shows what we're up against later today. A mature low pressure system in the Eastern Pacific around 40N137W is supporting a very long cold-type occluded front. As this front approaches the coast overnight, the rain intensity and wind strength will both increase. Winds will steadily increase through the day, peaking around midnight. Sustained winds of 15-25 mph are expected, with occasional gusts to 50 mph along the coast and in higher terrain. That's a little weaker than last week's storms, but still enough to cause tree damage and possible power outages. On average we're expecting about 1/2" of rain overnight, with up to 3" in the coastal mountains and closer to 1/4" in the rain shadowed valleys. && .LONG TERM... Issued at 1236 AM PST Fri Jan 2 2026 (Saturday through Thursday) After the front passes Saturday morning, the precipitation mode will switch from stratiform rain to convective showers. Some of these showers will be strong, and there is a decent chance for thunderstorms throughout the day Saturday as a few post frontal short wave troughs move through. The 06Z HRRR shows one of these pulses will line up well with the warmer, more unstable conditions in the afternoon. There is a marginal chance for severe thunderstorms in the North and East Bay, with tornadoes as the most likely severe threat in the typical low CAPE, high shear environment. High resolution model point soundings in the North Bay show around 100 J/kg of CAPE, with 40-50 kts of 0-1km shear, low LCL heights, and a nicely curved low level hodograph Saturday afternoon. The severe threat is focused on the North Bay, but not confined there. Landfalling waterspouts are possible along the coast. Reinforcing wet cold fronts will move through Sunday and Monday, with a much drier FROPA midweek. This parade of cold fronts will drop the 1000-500 mb thickness from 5,530 m today to 5,340 m by Friday, bringing snow levels to around 3,000 feet. If we can get any moisture late next week we'd have a real chance for some snow flakes in the higher peaks around the Bay Area and Central Coast. Otherwise we'll see temperatures drop back into the 30s for inland areas towards the end of next week as a drier, more stable pattern moves in. && .AVIATION... (06Z TAFS) Issued at 939 PM PST Thu Jan 1 2026 MVFR/IFR cigs expected to prevail for the North Bay overnight into early afternoon Friday, before lifting to VFR when winds begin to increase with prefrontal showers out ahead of the main line expect to begin moving onshore by early afternoon. Vicinity of SFO...Expect MVFR cigs to prevail overnight that may occasional lift to VFR, along with on-and-off light rain. By late morning Friday prefrontal winds begin to increase with scattered showers out ahead of the main line set to arrive onshore by late afternoon. Strong winds, scattered showers with thunderstorms are expected to prevail through the remainder of the TAF period into late Friday night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Expect cigs to hover around MVFR/VFR overnight, then becoming VFR by mid-morning. Wind, showers and thunderstorm activity arrives later than farther north with slightly less impactful winds and thunder storm coverage this far south. KSNS winds remain elevated through the TAF period with surface flow through the Salinas Valley. && .MARINE... (Tonight through next Wednesday) Issued at 939 PM PST Thu Jan 1 2026 Small Craft Advisories in the northern outer waters will become Gale Warnings late in the overnight period tonight, with the remaining outer and inner waters becoming Gale Warning by mid morning Friday. The remaining interior bays will have Small Craft Advisories by mid- afternoon Friday, with Monterey Bay in a Gale Warning during most of the overnight period Friday into early Saturday morning. There may be brief periods with Storm Force gusts in the far northern outer waters and inner waters off Big Sur Friday evening into early Saturday, but not over a large enough area or for a long enough period of time to hoist a Storm Warning at this time. The Gale Warnings off of Big Sur will remain in place through mid-morning Saturday, and the Gale Warnings in the northern half of the outer waters will remain place through Saturday afternoon. Along with the strong southerly winds, expect rough seas, moderate to heavy rain at times and a slight chance of thunderstorms. && .BEACHES... Issued at 1236 AM PST Fri Jan 2 2026 A Coastal Flood Warning is in effect for the San Francisco Bay through Saturday. A Coastal Flood Advisory is in effect for the Pacific Coast and Monterey Bay through Sunday. Perigean spring tides (king tides) will impact the region through Sunday. This is due to the combination of the full moon on 1/3, lunar perigee on 1/1, and perihelion on 1/3. In other words the earth, sun and moon are lined up and close to each other. In addition to the high astronomical tide, the incoming low pressure system will bring strong southerly winds, generating some storm surge, particularly on Saturday morning. The combination of these factors will bring moderate coastal flooding to the low-lying areas near shorelines and tidal waterways during high tide through Sunday. On Thursday, the San Francisco tidal gauge recorded 2.1 ft of inundation. Looking ahead, high tide is expected to be 2.2 ft above normal at 9:34 AM Friday, 2.5 ft above normal at 10:26 AM Saturday, and 1.9 ft above normal at 11:18 AM Sunday. These predictions include up to 1.3 feet of storm surge that will enhance the astronomical tide and flooding threat. A reasonable worse case scenario (10% exceedance chance) is 2.7 ft of inundation on Saturday. The all time record is 2.8 ft from 1/27/1983. 2.5 ft hasn't been reached since 1998. High tide varies up to 90 minutes earlier or later along the Pacific Coast and through the San Francisco Bay, respectively. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 7 AM PST this morning for CAZ006- 506-508. Coastal Flood Advisory from 2 PM Saturday to 2 PM PST Sunday for CAZ006-506-508. Coastal Flood Warning from 7 AM this morning to 2 PM PST Saturday for CAZ006-506-508. Wind Advisory from 1 PM this afternoon to 1 PM PST Saturday for CAZ006-502>505-509-512-515>518-528>530. Coastal Flood Advisory until 2 PM PST Sunday for CAZ505-509-529- 530. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PST Saturday for SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PST this evening for Mry Bay. Gale Warning from 9 PM this evening to 3 AM PST Saturday for Mry Bay. Small Craft Advisory until 9 AM PST this morning for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning from 9 AM this morning to 3 AM PST Saturday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 AM PST early this morning for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0- 10 nm. Gale Warning until 9 AM PST Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 PM PST Saturday for Pt Arena to Pt Reyes 10- 60 NM. && $$ SHORT TERM...Flynn LONG TERM....Flynn AVIATION...JM MARINE...JM 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