FXUS66 KMTR 131748 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1048 AM PDT Wed May 13 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1200 AM PDT Wed May 13 2026 - Cooling trend continues today - Warming and drying trend resumes Thursday through the weekend && .UPDATE... Issued at 717 AM PDT Wed May 13 2026 Stratus continues to linger across the SF Bay Area and Central Coast as a decaying cold front moves across the region, helping to mix out the lower layers. Breezy winds continued overnight and into the morning across favored ridgelines and coastal regions, with the winds expected to pick up through the day. DialH && .SHORT TERM... Issued at 1204 AM PDT Wed May 13 2026 (Today and tonight) A disjointed marine layer is trying to reform overnight per satellite fog product. Where it is reforming it's rather deep at 1500-2000 ft. The complicating factor in development of the marine layer is the passing upper low well to the north in OR and a trailing vort max/shortwave trough passing over region. Lastest guidance continues to advertise some expansion of the marine layer through sunrise, but it never completely fills in the "standard" marine layer footprint. Morning low clouds will give way to afternoon sunshine, even the coastal locations. The coastal clearing today will be enhanced by the increasing northerly gradients and stronger winds. SFO-ACV will ramp up to over 5 mb, which is decent. Winds will be strongest over the coastal waters this afternoon and immediate coastline with gusts of 25-45 mph possible. Despite some sunshine temperatures will be close to or below normal for mid May with highs in the 60s to lower 70s coast/bays and 70s to mid 80s inland. It will be the coldest day of the next seven. For tonight, not expecting a ton of marine stratus due to lingering stronger northerly flow and a departing upper level trough. && .LONG TERM... Issued at 1204 AM PDT Wed May 13 2026 (Thursday through Tuesday) By Thursday zonal flow develops over the region as high pressure begins to build, but is tampered by a trough near the Gulf of AK. The semi-zonal flow will continue through Friday. As such, a gradual warming and drying trend will develop. A blip in the longwave pattern with a sagging upper level trough over CA on Saturday will drop temperatures back to near or below seasonal averages. The sagging trough deepens and develops a low that sweeps into the Great Basin. Why is this important for our area? Pattern recognition points to bursts of offshore flow over the higher terrain each night into morning hours beginning Sunday into next week. This will lead to marginal humidity recovery at night. Not a big fire concern at this point, but something we'll need to monitor over the next few days. ERC charts are catching on with a trend line back toward daily maxes. More uncertainty for next week is around max temps Mon/Tue. While the longwave pattern shows troughing to the east and a ridge over the EPac it doesn't scream heat. The NBM is showing some rather warm temps with interior 90s again. Call it recency bias, but 850 mb not 20C+ gives me pause on max temps from the NBM. Other ens guidance is on the colder side and did verify better during our most recent warm spell. That being said, we'll need to watch this as well and trend temps down if needed. Stay tuned... && .AVIATION... (18Z TAFS) Issued at 1047 AM PDT Wed May 13 2026 Patchy stratus is clearing across the Bay Area and Central Coast with all sites expected to be VFR this afternoon/evening. Stratus is expected to be patchy tonight with the highest confidence in a late stratus return for coastal sites and along the bay shoreline. Wind gusts pick up rapidly this afternoon and evening with gusts to around 25-35 knots along the coast and 20-25 knots across portions of the interior. Winds decrease overnight with breezy conditions expected again during the afternoon/evening tomorrow. Vicinity of SFO...Strong west to northwest winds are expected through this evening with gusts between 25-35 knots. Winds ease overnight but are expected to pick up again tomorrow morning/afternoon. There is a slight chance for stratus to reach SFO after 10Z but confidence was too low to include in TAF given a much drier airmass expected to move in. SFO Bridge Approach....Generally similar to SFO but gusts look to be closer to 25-30 knots. Monterey Bay Terminals...Stratus will continue to dissipate through late this morning with VFR expected this afternoon/evening. Moderate confidence that stratus will reach MRY late tonight but confidence is lower that it will reach SNS. Breezy west to northwest winds are expected this afternoon/evening with gusts to around 20 knots expected. Winds ease overnight with gusty winds to return tomorrow afternoon. && .MARINE... (Today through Monday) Issued at 1047 AM PDT Wed May 13 2026 Hazardous marine conditions expected late week through the weekend. Winds will continue to increase through the work week with strong winds and near gale-force gusts possible today. Persistent gale-force winds affect the outer waters beginning Thursday, with gale force to severe gale winds expected to become widespread by Friday. Occasional storm force gusts are possible across the inner waters this weekend. Very high wind driven seas between 12 to 17 feet are expected. Winds stay hazardously strong through the weekend, but ease early to mid next week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Thursday for Mry Bay. Small Craft Advisory until 9 AM PDT Thursday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Gale Warning from 9 AM Thursday to 3 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm. Gale Watch from Friday afternoon through Saturday evening for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm- Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 PM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning from 9 AM Thursday to 9 AM PDT Friday for Pt Arena to Pt Reyes 10-60 NM. Gale Watch from Friday morning through Saturday evening for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 PM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM. Gale Warning from 9 PM Thursday to 9 AM PDT Friday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...MM LONG TERM....MM AVIATION...Kennedy MARINE...Kennedy 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