


Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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679 FXUS66 KMTR 152111 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 211 PM PDT Tue Jul 15 2025 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 209 PM PDT Tue Jul 15 2025 - Below seasonal temperatures continue through Thursday before a slight warming trend begins Friday into the weekend. - Localized elevated fire weather threat continues across the higher elevations. && .SHORT TERM... Issued at 209 PM PDT Tue Jul 15 2025 (This evening through Wednesday) Widespread stratus to return again tonight as the marine layer holds steady around 2000 ft in part thanks to persistent upper level troughing over the West Coast. Quite a few coastal sites (Half Moon Bay, Laguna Seca, Bodega Bay, Point Reyes) reported at least a hundredth of an inch of drizzle this morning. Coastal areas can expect to see patchy drizzle (similar to today) and fog again tomorrow morning as low level clouds move in overnight. In terms of temperatures, today marked the beginning of a slight cooling trend with seasonal to below normal temperatures to continue through the end of this week. Temperatures across the interior are forecast to be between 5 to 10 degrees below normal tomorrow with highs largely in the 70s to 80s across the interior. Far interior East Bay (Byron area) and far interior Central Coast (Fort Hunter Liggett, Bradley)continue to be the two hot spot regions with highs peaking in the upper 80s to possibly low 90s. Generally the below normal temperatures and deeper marine layer are helping to mitigate fire weather concerns for the lower elevations, but for areas above the marine layer (~2000+ ft in elevation) dry conditions continue with only minor improvements in overnight humidity recoveries/daytime humidity retention. Winds remain light and onshore through the period with the exception of mountain ridgetops, mountain gaps/passes, and areas where terrain funneling is able to occur (valleys). Diurnally breezy conditions are expected across these areas with gusts to around 25 mph anticipated. The breeziest conditions will be in the vicinity of the Altamont Pass where gusts will peak closer to 30 to 35 mph. && .LONG TERM... Issued at 209 PM PDT Tue Jul 15 2025 (Wednesday night through next Monday) Not too many changes in the Long Term forecast, weak upper level troughing will generally keep temperatures below normal through Thursday with highs in the upper 70s to mid 80s. A slight warming trend begins Friday into the weekend as our persistent upper level trough weakens and is forced northward towards the PNW by redeveloping high pressure over the Pacific Ocean. As the trough is pushed northward, high pressure located over the Four Corners region will expand and push into the Bay Area and Central Coast. This will result in our marine layer compressing (limiting the inward extent of stratus overnight) and allow temperatures to warm more across the interior. This will bring temperatures closer to normal across the interior with highs in the upper 70s to 80s. For far interior locations and locations above the marine layer (~2000 ft), temperatures will be seasonal to slightly above normal in the mid to upper 90s. HeatRisk concerns are minor through the end of the forecast period with good overnight cooling into the mid 50s to low 60s expected. Fire weather concerns remain minimal across the lower elevations but remain locally elevated across the higher elevations above the marine layer. Conditions dry out above 2000-2500 ft Friday through the weekend with overnight humidity recoveries between 20- 35% and daytime humidity retention between 15-25%. Winds remain onshore but are expected to be diurnally breezy through mountain gaps/passes, along ridgetops, and across areas where terrain funneling is likely (valleys). Anyone visiting the mountains should keep in mind the saying, one less spark, one less wildfire. Temperatures start to cool again Monday, returning to seasonal to slightly below normal temperatures, as upper level high pressure weakens and a cut-off low in the Pacific Ocean tries to strengthen and push towards the West Coast. Hopefully Bay Area/Central Coast residents are not fully opposed to the relatively mild summer that we have had so far as the CPC indicates temperatures will lean below normal through the end of July. && .AVIATION... (18Z TAFS) Issued at 1030 AM PDT Tue Jul 15 2025 Currently a mixed bag of IFR-VFR at the terminals. An upper-level shortwave trough helped deepen the marine layer to 2,200 feet and produce coastal drizzle. A second upper-level shortwave trough will approach the region towards the end of the TAF period, so all in all, a persistence forecast is on tap. Vicinity of SFO...Currently VFR with northerly flow. Westerly flow will return once the sea breeze kicks in this afternoon. High confidence (up to 80%) in an MVFR ceiling developing tonight. SFO Bridge Approach...Low stratus clouds will begin to filter in through the Golden Gate Gap late this afternoon and linger through tomorrow morning. Monterey Bay Terminals...Currently IFR with southwesterly flow at MRY and MVFR with northwesterly flow at SNS. High confidence in IFR ceilings returning to both terminals tonight. && .MARINE... (Today through Sunday) Issued at 925 AM PDT Tue Jul 15 2025 Localized hazardous marine conditions in the form of strong northerly breezes and very rough seas will continue through this afternoon for the northern outer waters. Wednesday through Saturday will bring widespread gentle to moderate breezes and moderate seas. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...Sarment MARINE...Sarment 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