486 FXUS66 KMTR 210417 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 917 PM PDT Fri Jun 20 2025 ...New UPDATE, MARINE... .SYNOPSIS... Issued at 1257 PM PDT Fri Jun 20 2025 Seasonably cool temperatures through this weekend with windy conditions. Elevated fire weather concerns continue into Sunday morning as gusty winds combine with dry conditions. Return to normal temps and quiet conditions by early next week. && .UPDATE... Issued at 917 PM PDT Fri Jun 20 2025 It has been a windy day across the Bay Area with SFO notably gusting to 53 mph at 7:56 PM this evening. Winds will remain gusty overnight before peaking Saturday morning/afternoon. The overall forecast remains on track with winds set to diminish Sunday into next week as an upper level trough moves eastward. In terms of fire weather, daytime relative humidity values dropped into the teens to 20s across the North Bay Interior Mountains and interior Central Coast. Fire weather conditions will remain near critical through Saturday across the higher elevations of the North Bay Interior Mountains, Interior Central Coast, and East Bay Hills as gusty winds and dry conditions continue. && .SHORT TERM... (This evening through Saturday) Issued at 1257 PM PDT Fri Jun 20 2025 Mostly clear skies across the region today a gusty NW winds ramp up. Current winds gusting in the 25-35 mph range across some of the more wind-prone gaps and passes. Most notably up to about 40 mph at Altamont. Winds are expected to remain gusty through tonight as a deep upper low digs into the Great Basin. Due to the positioning of the low and juxtaposition of the upper level jet, winds will largely remain onshore through the event, which is a bit of a silver lining, keeping the marine layer moisture present below about 2000 feet. For areas above the marine layer, very dry afternoon RH and limited overnight recovery will present an elevated fire weather threat thanks to dry grasses and shrubbery. && .LONG TERM... (Saturday night through next Thursday) Issued at 1257 PM PDT Fri Jun 20 2025 The peak of the winds looks to be Saturday during the early morning hours, but gusty conditions will linger through into Sunday morning. Towards the end of the event Monday morning, there is a small chance that the winds make a turn towards a more offshore direction, but by the time the surface pressure gradient supports this, much of the upper level support from the system will have moved on. Therefore, we aren`t expecting any offshore wind component Monday morning to have much more than a very minor impact as of this forecast issuance. For the rest of the period, a more "normal" pattern is restore as a ridge builds over our region and subtle troughing to the north subdues any substantial warming. Thus, we return to seasonable temperatures and relatively quiet conditions next week. && .AVIATION... (00Z TAFS) Issued at 516 PM PDT Fri Jun 20 2025 VFR through the TAF period. Stronger winds last into the night before reducing. Winds along the coast will still be breezy and gusty, while surface winds in more inland areas become more moderate. However, winds aloft will remain strong, causing LLWS concerns, specifically at STS, which will have strong winds at 1000 ft AGL. Winds aloft and at the surface reduce further into Saturday morning, but stay breezy along the coast. Winds build across the region again into Saturday afternoon, but do not look to be as strong as the current winds. Vicinity of SFO...VFR through the TAF period. Strong and gusty west winds last into the night before reducing by 10 kts in both winds and gusts. Expect gusts to cut off and winds to reduce slightly into early Saturday, keeping winds moderate through the morning and into the early afternoon. Gusty winds return for Saturday afternoon with around 30 kt gusts on top of 24 kt winds. These winds and gusts reduce into the early night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Breezy and gusty winds last into the night before reducing, becoming moderate for MRY, but still seeing some southwest breezes at SNS. Cloud cover looks to form just outside of MRY in the late night and early morning to the south and east, but does not look to fill over MRY. Skies clear into the mid morning. && .MARINE... (Tonight through next Thursday) Issued at 917 PM PDT Fri Jun 20 2025 Strong gusts and rough seas are producing hazardous marine conditions continue through the first half of Sunday before winds reduce. Seas look to be slower to ease but will improve into the next work week. Breezy but less strong winds linger for the first part of the next work week as well. && .FIRE WEATHER... Issued at 323 AM PDT Fri Jun 20 2025 Elevated fire weather conditions continue today across the interior becoming more widespread on Saturday, with RH values around 30% expected across the interior of the East Bay south through the Gabilan Range, along with the Santa Lucia mountains this afternoon. Gusty winds above the marine layer and elevated interior locations will once again be around 25 to 40 mph with less coverage today than Thursday. Brief periods of critical fire weather conditions are possible with daytime relative humidities of 15 to 25% in the interior. However, continuing marine layer influence, especially during the night, and the fact that winds remain onshore, mean that widespread critical fire conditions do not develop across the district. Gusty winds begin to subside somewhat on Saturday, but the upper level pattern will lead to more northerly winds developing across the region. As with Thursday`s fire weather threat, widespread critical fire weather conditions are not expected within the district, although the fire weather threat will increase once again for areas closer to the Central Valley. The fire weather threat will continue to diminish Sunday into the early part of next week with the gusty winds further relaxing, although humidity values in the interior will be slow to rise. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Sunday for Mry Bay-SF Bay N of Bay Bridge. Gale Warning until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 10- 60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning until 3 AM PDT Saturday for Pt Reyes to Pigeon Pt 0- 10 nm. Gale Warning from 3 PM Saturday to 3 AM PDT Sunday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 AM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Gale Warning from 9 AM Saturday to 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Behringer LONG TERM....Behringer 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