700 FXUS66 KMTR 091130 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 430 AM PDT Wed Jul 9 2025 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 101 AM PDT Wed Jul 9 2025 - Warming trend begins today through the weekend, with patchy Moderate HeatRisk across the Bay Area and Central Coast Thursday and Friday. - Localized elevated fire weather threat starting today through the weekend across the higher elevations. && .SHORT TERM... Issued at 101 AM PDT Wed Jul 9 2025 (Today and tonight) Satellite imagery shows widespread marine layer stratus across the valleys of the Bay Area and Central Coast, as data from the Fort Ord profiler shows the top of the marine layer becoming more diffuse while rising to at least 3000 feet over the last evening. Low temperatures this morning will hover in the lower to middle 50s in the lower elevations, and as high as the lower 60s in the highest peaks. Today marks a pattern change from the cooler regime of the last few days to a warming pattern that (spoiler alert) looks to set up for the rest of the week. The upper level low that brought us the robust marine layer and the cool temperatures is dissipating while it meanders towards landfall in the North Coast. This will allow an ridge that`s set up over the desert Southwest to edge into the state while a synoptic high pressure system develops in the east Pacific, causing temperatures to warm. Temperatures will range from the upper 70s to the middle 80s inland, with the warmest spots in southern Monterey and San Benito Counties reaching the upper 90s, while locations on the Bays reach highs in the upper 60s and the 70s. The marine layer will compress, but the coastal areas should remain rather cool with highs in the upper 50s to the lower 60s. Some elevated fire weather threat is forecast to develop today across areas above and inland of the marine layer`s influence. The combination of dry daytime humidities of around 15-30% and localized gusts to 30 mp will be the main factors behind the elevated threat. However, the winds will remain onshore, leading to the fire weather threat being diurnally driven, especially in the foothills where lighter winds and good overnight recoveries are expected each night. && .LONG TERM... Issued at 101 AM PDT Wed Jul 9 2025 (Thursday through Tuesday) Temperatures continue to rise on Thursday and Friday as the high pressure systems become more established, with the inland valleys seeing highs in the middle 80s to middle 90s on both days, while the warmest interior locations see temperatures rising up to a few degrees above 100. Patches of Moderate HeatRisk are expected on Thursday and Friday across the interior North Bay, East Bay, and South Bay, in addition to the Santa Lucia mountains and the southern tip of San Benito County. Remember to take frequent cooling breaks and drink plenty of water if participating in outdoor activities on both days. As a very weak upper level disturbance passes through the state this weekend, temperatures will cool slightly to the lower 80s to lower 90s in the interior Bay Area with an shortwave trough coming through the West Coast, while the interior Central Coast remains rather warm with temperatures in the 90s. The pattern will otherwise remain rather stable through the early part of next week, with warm inland temperatures, cool coastal temperatures, light onshore winds, and localized elevated fire weather threat in the interior developing each afternoon. && .AVIATION... (12Z TAFS) Issued at 419 AM PDT Wed Jul 9 2025 MVFR to LIFR ceilings early this morning with a robust marine layer in place. Conditions will persist through most of the morning into the early afternoon for some spots. Expect some breezy periods of onshore flow this afternoon with a return of low stratus ceilings around sunset for most, after midnight for the North Bay locations. Vicinity of SFO...MVFR/IFR stratus ceilings will persist through the late morning, clear out for much of the afternoon and early evening, then returning around sunset with a 2500` marine layer in place. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR/LIFR persisting through most of the morning with clearing expected around noon. HiRes guidance is anticipating a later clearing this morning than yesterday and earlier return this evening with the marine layer topping out at 2500`. Onshore flow may breezy at times this afternoon. && .MARINE... (Today through Monday) Issued at 419 AM PDT Wed Jul 9 2025 Winds will begin to increase out of the north this afternoon and continue to strengthen through Wednesday night becoming fresh to strong for Thursday into the weekend. Rough to very rough significant wave heights will also persist into the weekend for the outer waters. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Thursday for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...DialH LONG TERM....DialH 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