


Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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728 FXUS66 KMTR 140938 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 238 AM PDT Tue Oct 14 2025 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 236 AM PDT Tue Oct 14 2025 - Post-frontal rain showers and up to a 15% chance for thunderstorms today - Warming and drying trend Wednesday through Saturday - Unsettled weather returns Sunday && .SHORT TERM... Issued at 236 AM PDT Tue Oct 14 2025 (Today and tonight) All signs point to rain shower/thunderstorm activity declining through the day as the surface low pressure system and it`s attendant cold front (as well as it`s mid-to-upper level support) will weaken and exit the region through the day. There will still be chances for rain showers and thunderstorms until the features exit around midnight. Let`s take a deep dive into the thunderstorm potential for today by addressing the critical ingredients of lift, instability, and moisture. In addition to what has already been discussed lift wise, a 95 knot jet streak from a dive in the Polar Jet Stream will shift into our region today, which could allow for more ascent. Instability will be characterized by low CAPE (500 Joules/kilogram) and conditionally unstable lapse rates (7 degrees Celsius/kilometer). Moisture will ebb and flow throughout the day and will be highly dependent upon the placement of the surface low pressure system. A solution over the water will be more moist than a solution inland which will be capable of entraining drier air into the system. With similar ingredients on tap for today as what was present yesterday, I would be very surprised if today outperformed yesterday given the very limited amount of lightning that was observed. The best chances for thunderstorms (up to 15%) are for Southern Monterey and San Benito Counties and the adjacent waters. Thunderstorm or not, cells will still be capable of producing locally heavy rainfall resulting in nuisance/urban flooding, erratic/gusty winds, small hail, and waterspouts. Caution should continue to be exercised through the day when driving. Roads will still be wet for this morning`s commute so please allow extra patience, space, and time when driving, especially for super commuters who will undoubtedly be driving in the dark. Remember: turn around, don`t drown! This system is also a cold one. Calm, clear, and cold conditions tonight will yield near-freezing temperatures for far interior Monterey and San Benito Counties east of Highway 101. In addition to the aforementioned near-freezing temperatures, patchy frost will be possible in sheltered locations east of Highway 101 in Monterey and San Benito Counties. While there`s not great consensus amongst guidance/models, the potential will be there for fog to develop tonight. The limiting factor will likely be cloud cover as it would allow for less efficient radiative cooling. && .LONG TERM... Issued at 236 AM PDT Tue Oct 14 2025 (Wednesday through Monday) Global ensemble clusters are in agreement that upper-level shortwave ridging will nose in from the Eastern Pacific Ocean by Wednesday. At the surface, high pressure will also nose in from the Eastern Pacific Ocean and build into the Pacific Northwest through Thursday. This will translate to a northerly (drying) gradient developing across California. By Friday and into Saturday, the high pressure builds into the Great Basin while a coastal trough develops off the coast of California. This will result in light offshore flow for these two days. Fortunately, just coming off the heels of a widespread wetting rain event, this warming and drying trend will not be a fire weather concern. Global ensemble clusters are in agreement that heights will fall Sunday with an approaching upper- level longwave trough. Confidence quickly plummets by Monday as there is near split percentages on if troughing will continue to dig into the region or if high pressure will rebuild. Nonetheless, at least expect an increase in cloud cover and wind towards the end of the forecast. While the current forecast is dry, there is potential for rain returning to the forecast with ECMWF and GFS total precipitation ensemble spread showing a three inch disparity. && .AVIATION... (06Z TAFS) Issued at 955 PM PDT Mon Oct 13 2025 The main frontal band of rain, and its attendant reduced visibilities and gusty winds, has moved into the interior portions of the Bay Area but is still making its way through the Central Coast. Overnight, winds will generally be light and mostly driven by local effects, with generally VFR conditions with mid-level ceilings possible. A chance for scattered showers and isolated thunderstorms continues across the region through Tuesday with reduced visibilities and gusty winds expected within and near the thunderstorm cells. In addition, the North Bay could see steadier light rain from the backside of the frontal system through Tuesday morning. Otherwise, afternoon winds will be muted on Tuesday with hints of a weak onshore flow within the models. In the post-frontal environment, ceilings are tricky to forecast, but indications point to generally VFR conditions with mid-level ceilings outside of the strongest storms, barring the North Bay where MVFR ceilings could accompany the steady rain. Vicinity of SFO... Moderate confidence of VFR with mid-level ceilings through the TAF period. Chance for scattered showers with isolated thunderstorms continues through Tuesday morning, with the main impacts being reduced visibilities and gusty winds if one develops over the terminal. Otherwise winds will be weakly onshore with gusts reaching 8 kt. Some divergence in the model outputs towards the end of the TAF period with some high resolution models pointing to southerly winds Tuesday night. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals... The main rain band is expected to push out of the terminal areas within the next couple of hours. VFR with mid- level ceilings persists through the TAF period with light drainage winds overnight followed by breezy west winds Tuesday afternoon. Isolated showers and thunderstorms are possible through Tuesday morning with the main impacts being reduced visibilities and gusty winds if one forms or moves over a terminal. && .MARINE... (Tonight through next Sunday) Issued at 845 PM PDT Mon Oct 13 2025 The strongest winds and heaviest rains have moved inland, but a chance for showers and isolated thunderstorms persists through Tuesday morning. The showers will become more isolated while the winds decrease overall. Rough seas to 10 feet will persist into Wednesday, then becoming moderate through late Thursday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Sarment LONG TERM....Sarment AVIATION...DialH 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