682 FXUS66 KMTR 041910 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1210 PM PDT Fri Jul 4 2025 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 1209 PM PDT Fri Jul 4 2025 - Elevated fire weather threat continues through Friday evening for the East Bay and Santa Cruz Mountains. - Northwest winds of 30 to 50 mph Friday afternoon and evening across gaps, passes, and some valleys. - Temperatures remain below seasonal averages into early next week, with a gradual warming trend towards the later part of next week. && .SHORT TERM... Issued at 1209 PM PDT Fri Jul 4 2025 (This evening through Saturday) Satellite imagery reveals generally clear skies across the region with the immediate coast south of Big Sur the last refuge of the coastal stratus. Broad upper level troughing continues to dominate the weather with temperatures near or below seasonal averages. Highs will reach the middle 70s to the lower 80s in the inland valleys, to the lower 90s in the southern reaches of Monterey and San Benito County, the middle 60s to lower 70s near the Bays, and the upper 50s to the middle 60s at the Pacific coast. Breezy and gusty afternoon winds will develop across the region, with gusts reaching 30 to 50 mph through the gaps and passes, along the coast, and through the Salinas Valley. As the evening goes on, patchy low clouds could develop along the coast and on the west side of the Berkeley-San Leandro Hills, but most regions should remain clear through early Saturday morning. The City, in particular, could very well remain clear throughout its July 4th celebration tonight. By 9 PM, the temperatures should cool to the middle 50s to lower 60s for most of the region, with the higher elevations remaining significantly warmer (up to the middle 70s). As a reminder, be careful when celebrating the holiday, especially if your plans involve fireworks or open flames (including grilling). With the gusty winds and dry conditions inland, particularly the higher elevations of the East Bay and the Santa Cruz range, elevated fire weather threats continue into the evening. One less spark, one less fire! Low temperatures on Saturday morning drop into the upper 40s to the middle 50s for the lower elevations and up to the lower 60s for the highest peaks. A few degrees of warming are possible on Saturday as the upper level trough erodes, but the overall pattern remains similar. && .LONG TERM... Issued at 1209 PM PDT Fri Jul 4 2025 (Saturday night through next Thursday) Sunday should see a cutoff low splitting from the remnants of the trough and setting up just off our coastline, leaving temperatures cooler than the seasonal averages into the early part of next week. The marine layer will also expand, allowing for further inland stratus intrusions, while breezy onshore flow continues with a southerly component, although the wind gusts are not expected to be as strong as those seen yesterday and today. The low pressure system weakens and meanders northward late Monday into Tuesday, allowing an upper level ridge over the Desert Southwest to build and a warming trend to start. This event looks to be similar to the previous warm periods we`ve had, where the coastal regions remain relatively cool while the interior regions heat up. By the end of the upcoming work week, temperatures near 100 are possible in the warmest spots, leading to areas of Moderate HeatRisk, corresponding to a moderate risk for heat-related illnesses for populations sensitive to heat. Some uncertainty still remains regarding the evolution of the upper level low and the evolution of the ridge, so stay tuned as the long range heat potential is refined through the next few days. && .AVIATION... (18Z TAFS) Issued at 1036 AM PDT Fri Jul 4 2025 VFR conditions at all sites expect for HAF where MVFR persists, yet should scatter out here by early afternoon. High confidence for onshore winds to increase this afternoon before easing after sunset. Moderate confidence for IFR/MVFR ceilings to return around the Monterey Bay terminals either late this evening or early Saturday morning. Low confidence for a return of MVFR (potentially as low as IFR) around the Bay Area terminals around sunrise Saturday morning. If any low ceilings do develop, the greatest potential will be at OAK and will scatter out by around 16Z Saturday. Onshore winds increase once again by Saturday afternoon with most sites returning to VFR. Vicinity of SFO...VFR. Onshore winds increase this afternoon with gusts up to 30kt. Winds ease slightly after sunset and then moreso into Saturday morning. Low confidence for MVFR ceilings to return over the SFO, yet greater potential at OAK early Saturday morning. Any low clouds that do develop with scatter out and/or dissipate around 16Z Saturday with increasing onshore winds by Saturday afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. Onshore winds increase this afternoon and gradually diminish after sunset. Moderate confidence for MVFR ceilings to return late this evening or early Saturday morning at MRY, slightly lower confidence for ceilings to return at SNS. Any low clouds that do develop will lower to IFR by sunrise before lifting and scattering out by late Saturday morning. && .MARINE... (Today through Wednesday) Issued at 818 AM PDT Fri Jul 4 2025 Fresh to strong northwest breezes and moderate seas continue through the weekend before winds ease early next week. Low- amplitude long period south swell will continue through the end of next week. Winds look to increase and significant wave heights look to build beginning late next week. && .FIRE WEATHER... Issued at 3 AM PDT Thu Jul 4 2025 Breezy onshore flow persist overnight with gusts 30-50 mph. Thankfully, most areas are seeing some marine influence with at least moderate humidity recovery. Winds may ease slightly before sunrise. Onshore flow will ramp back up this afternoon as the Central Valleys heats up. RH values will drop, but be tempered by onshore flow keeping them from really bottoming out. That being said, strong winds for inland gaps/passes and moderate RH will lead to elevated or near critical fire weather concerns. Grasses and finer fuels remain cured and available, and given the potential for new ignitions due to the holiday weekend, an increase in initial attack type activity should be expected by local fire personnel. Less favorable burn conditions are anticipated this weekend as the marine layer deepens and invades parts of the area. However, far interior portions of the Bay Area and Central Coast, as well as regions above 1500-2000 feet may still remain within an airmass characterized by near-critical humidity and winds where there may remain some potential for fire spread/growth. MM/Bain && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF Bay N of Bay Bridge. Small Craft Advisory from 3 PM to 9 PM PDT Saturday for SF Bay N of Bay Bridge. Small Craft Advisory from 9 AM to 9 PM PDT Saturday for Mry Bay. Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 AM PDT Saturday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory from 9 AM Saturday to 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm. Gale Warning until 3 AM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...RGass MARINE...DialH 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