FXUS66 KMTR 090943 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 143 AM PST Tue Dec 9 2025 ...New SHORT TERM, LONG TERM, BEACHES... .KEY MESSAGES... Updated at 132 AM PST Tue Dec 9 2025 - Tule fog and stratus will clear this afternoon - Quiet weather with warmer temperatures through Friday - Light rain possible next week && .SHORT TERM... Issued at 132 AM PST Tue Dec 9 2025 (Today and tonight) Another round of morning clouds and patchy fog across the Bay Area. The coverage is less than yesterday and these clouds will clear in the afternoon as temperature climbs a few degrees warmer than recent days. The prolonged ridging pattern continues with the amplitude notching up over the next few days. The Eastern Pacific high now extends a ridge across northern California, and there is even a somewhat uncommon cut off high way up at 250 mb directly over the Bay Area. This is the jet stream altitude where the average wind speed this time of year is around 60 knots. We'll be lucky to break 10 knots on the 12Z sounding. This vertically stacked dome of high pressure is leading to widespread subsidence, calm winds, stagnant surface air, and warmer than normal temperatures. && .LONG TERM... Issued at 132 AM PST Tue Dec 9 2025 (Wednesday through Monday) While the ridge has been the main scapegoat for the ongoing Tule Fog, the increasing ridge intensity will compress this cool moist layer closer to the surface and limit it's horizontal spread to the Central Valley and colder interior valleys across the Bay Area. Air quality may also suffer as a result. The 850 mb temperature will climb to around 17C by Wednesday, and park there until Friday. That's around 10C warmer than normal, close to the average for June. Surface temperatures will respond and warm up to 10F above normal, pushing some clear areas of the Bay Area and Central Coast to the mid 70s. This heat will peak on Thursday with noticeable cooling by the weekend. Despite the warm afternoons, the dry atmosphere (PW 0.3- 0.5") and long December nights will still bring morning temperatures into the 40s. The ridge axis will finally move through this weekend, allowing the pattern to become more zonal. This opens the door for some rain next week. While zonal flow doesn't support strong storms or atmospheric rivers, it looks likely that we'll at least end the dry streak sometime next week, possibly as early as Monday. && .AVIATION... (06Z TAFS) Issued at 948 PM PST Mon Dec 8 2025 Low clouds and fog have reformed in the North Bay and interior East Bay. SFO and SJC see CIGs arrive in the late night with some slight reductions in visibilities. Winds stay mostly light to moderate through the TAF period, with wind directions determined by more localized affects. Cloud cover and fog will be slow to erode into Wednesday afternoon, but conditions look to improve into the late afternoon. However, the North and East Bay will continue to struggle with low clouds and fog, causing some doubt for clearing at APC. As cloud cover erodes, pockets of haze will affect much of the region. Winds reduce again into Wednesday evening with fog and low cloud looking again to reform in the North Bay and interior East Bay. Vicinity of SFO...VFR lasts into the late night. Winds become lighter into the night with scattered low clouds building into the area, along with some slight reduction in visibilities. IFR level CIGs fill into the late night with some weak easterly winds. Cloud cover thins into the afternoon, but winds stay light and turn slightly more northerly. These wind look to become light and variable into the late evening. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Winds stay light for MRY through the TAF period, while SNS sees moderate westnorthwest rebuild into Wednesday afternoon. These winds become light and variable into that night. && .MARINE... (Tonight through next Sunday) Issued at 948 PM PST Mon Dec 8 2025 North and northwest flow continues with moderate to fresh winds continuing south of Point Sur. Winds increase to a strong breeze Tuesday into mid week across the outer waters. A new, long period northwesterly swell is expected by midday Wednesday,lasting into the early weekend. && .BEACHES... Issued at 132 AM PST Tue Dec 9 2025 Long period swell will impact the coast Wednesday - Friday. This energy brings strong rip currents, an increased risk for sneaker waves, and large breaking waves. NW swell around 8 feet with a 15 second period will translate to breaking waves up to 15-20 feet. These conditions may warrant a Beach Hazards Statement, particularly with the warm weather likely luring more people to the Beach. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PST this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...Flynn LONG TERM....Flynn 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