FXUS66 KMTR 030810 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1210 AM PST Sat Jan 3 2026 ...New SHORT TERM, LONG TERM, BEACHES... .KEY MESSAGES... Updated at 1201 AM PST Sat Jan 3 2026 - High astronomical tides combined with storm surge will bring substantial tidal flooding through Sunday - Strong southerly winds continue into Saturday afternoon - Chance of thunderstorms through the weekend - Hazardous beach conditions Sunday - Daily rain showers expected through Monday && .SHORT TERM... Issued at 1201 AM PST Sat Jan 3 2026 (Today and tonight) The occluded front is just off the coast, and the triple point should make landfall in the Bay Area around 4 AM. The more organized band of rain associated with this frontal passage has reached the North Bay and will push south through the early morning hours. Overall the rain has been somewhat underwhelming compared to our expectations. Outside of the mountains, nowhere has recorded more than 1" of rain, with less than 1/4" across the SF Peninsula, East Bay, and South Bay. While we haven't seen thunderstorms yet, we've just started to see 40 dBZ at the -10C level, increasing confidence that we're approaching the ice content necessary to generate lightning. After the front passes the rain will transition to scattered showers, some of which could be strong. We have a renewed chance for thunderstorms in the more unstable atmosphere through the day Saturday, particularly in the North Bay. A RAP13 point sounding at Santa Rosa shows the instability peaking around 1 PM. According to this model, the surface based CAPE reaches an impressive 676 J/kg, with steep low-level lapse rates (-7.4 C/km), decent 0-1 km shear (25 kt) in a slightly curved hodograph, and low LCL heights (394m). If we can manage to find a trigger to tap into this energy in an organized manner, a line of thunderstorms could develop across the North Bay in the afternoon and push south through the evening ahead of the next frontal passage Sunday morning. With the moderate shear, we can't rule out severe thunderstorms. There is only a marginal chance, but damaging wind gusts and short lived tornadoes are the primary hazard if any thunderstorms can manage to become severe. The Sunday front will bring similar impacts to the ongoing system, although the rain will continue past dawn, so the impact from the rain will likely be higher. Winds, on the other hand, will decrease to a moderate breeze, and the thunderstorm threat will abate through the day. While river flooding isn't a major concern, the USGS is reporting saturated soils. If any heavy showers bring high rain rates they could trigger shallow landslides. && .LONG TERM... Issued at 1201 AM PST Sat Jan 3 2026 (Sunday through Friday) Showers with a slight chance of thunderstorms will persist Sunday night into the beginning of the new work week, especially for the North Bay. The upper level low currently responsible for our windy and rainy weather overnight, will lift north during the day today and be re-absorbed by yet another disturbance off the coast of the Pacific Northwest. The trough associated with the exiting low, will be reinvigorated over the next 48hrs and bring another round of widespread rainfall Monday into early Tuesday. The coastal ranges will be favored for the highest rain totals but the spigot doesn't appear to shut off until Wednesday when we see amplified ridging begin to build over the eastern Pacific in the wake of the final upper low shifting south offshore on Tuesday. The coastal ranges may see 1-2" of rainfall Monday into Tuesday with lesser amounts for the remainder of our area, around 0.25"-0.75" where it does rain. There's a chance next weekend could be a good one, with Climate Prediction Center highlighting the possibility in the 6-10 day outlook. && .AVIATION... (06Z TAFS) Issued at 951 PM PST Fri Jan 2 2026 Stronger south to southeasterly winds and gusts continue. Widespread rains will reduce visibilities this evening and into the night as the front moves through the area. Winds remain gusty in the post- frontal environment with less-organized lines of showers and a few storms moving through the area overnight. Airspace above the marine environment will see the better chances for storms, but some will make their way over land. The current forecast shows rain chances reducing across the board in the early morning, but rebuild into the mid to late morning. Expect winds and gusts to reduce into Saturday afternoon. Shower activity increase again into Saturday night. Cloud cover mostly sticks to the mid-levels through the TAF period with exceptions being periods of IFR/MVFR-level clouds in the North Bay and at HAF. Vicinity of SFO...Southeast winds are increasing with gusts above30 kts expected into early Saturday morning. Rain chances increase through the into the night, causing reductions in visibilities from the moderate to, at times, elevated rain rates. Rain turns to spottier showers in the early morning with slight chances for storms possible. Rain chances increase slightly into the mid morning, but reduce again in the afternoon as gusts cut off. Showers increase again Saturday night and exit into Sunday morning. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Moderate showers are arriving with breezy to gusty southerly to southeasterly winds. Visibilities will lower as these showers come through the area, with. Rain chances and winds reduce into early Saturday afternoon. Shower chances rebuild again into Saturday night. && .MARINE... (Tonight through next Thursday) Issued at 846 PM PST Fri Jan 2 2026 Gale force winds continue across the waters with localized storm force winds expected across the northern outer waters and along the Big Sur Coast. Winds diminish slightly Saturday with gale force winds across the northern waters and near gale force winds elsewhere. Seas build to 12 to 16 feet this weekend before abating early next week. Moderate rain and a slight chance of thunderstorms continues through the weekend. && .BEACHES... Issued at 1201 AM PST Sat Jan 3 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 Friday, the San Francisco tidal gauge recorded 2.26 ft of inundation. Looking ahead, high tide is expected to be 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. A Beach Hazard Statement is in effect Sunday. Large swell will impact the Pacific beaches, generating large breaking waves up to 20 feet, strong rip currents, and sneaker waves. Inexperienced swimmers should avoid the water. Nobody should climb the coastal rocks. Never turn your back on the ocean. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Warning until 2 PM PST this afternoon for CAZ006- 506-508. Wind Advisory until 1 PM PST this afternoon for CAZ006-502>505- 509-512-514>518-528>530. Coastal Flood Advisory from 2 PM this afternoon to 2 PM PST Sunday for CAZ006-506-508. Beach Hazards Statement from Sunday morning through Sunday evening for CAZ006-505-509-529-530. Coastal Flood Advisory until 2 PM PST Sunday for CAZ505-509-529- 530. PZ...Small Craft Advisory until 9 PM PST this evening for SF Bay N of Bay Bridge. Gale Warning until 3 AM PST early this morning for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning until 3 PM PST this afternoon for Pt Arena to Pt Reyes 0-10 nm. Gale Warning until 9 AM PST this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 9 PM PST this evening for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Flynn LONG TERM....JM AVIATION...Murdock MARINE...Murdock 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