916 FXUS66 KMTR 102111 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 211 PM PDT Tue Jun 10 2025 ...New SYNOPSIS, SHORT TERM, LONG TERM... .SYNOPSIS... Issued at 207 PM PDT Tue Jun 10 2025 Daily pattern of the return of marine layer clouds overnight through the morning hours, some coastal drizzle, and breezy afternoon onshore winds continues for much of this week. Temperatures remain in the upper 70s to 80s across the interior for much of this week as the pattern remains fairly quiet. && .SHORT TERM... (This evening through Wednesday) Issued at 207 PM PDT Tue Jun 10 2025 "June Gloom" continues to be the predominant theme of the short term forecast with stratus set to return across much of the CWA tonight into Wednesday morning. The 12Z OAK sounding shows the marine layer at a depth of approximately 2000 ft which allowed stratus to filter into much of the interior Bay Area and Central Coast. A look at the current temperatures (as of 1 PM) show most sites are mostly on track with the observed temperatures coming within 1-2 degrees of the hourly forecast temperature. High temperatures today will generally be in the mid 70s to 80s across the Bay Area and portions of the Central Coast. The two caveats to this will be temperatures for coastal areas will stay in the 60s and temperatures across the far interior Central Coast will reach the 90s to low 100s. Forecast guidance from the WRF keeps the marine layer closer to 1000 ft tonight, however, guidance has consistently been underestimating marine layer depth for much of this week. Both the ECMWF and GFS models show a weak upper level shortwave trough moving through Tuesday night into Wednesday. In terms of forecasting the marine layer, an upper level low (or in this case a shortwave trough) would allow the marine layer to deepen while building upper level ridging or high pressure would serve to compress the marine layer. The passage of this weak shortwave trough would then support our marine layer either maintaining a depth around 2000 ft or potentially deepening slightly and result in stratus spreading across much of the interior. Given that the marine layer depth is expected to be around 2000 ft again tonight, confidence is low that fog will develop but patchy drizzle is possible along the coastline. Stratus coverage is expected dissipate mid to late morning across the interior while it looks to stick around through the late morning for coastal areas. High temperatures on Wednesday will be similar to today if a few degrees cooler. High temperatures across the interior Bay Area will be in the 70s to low 80s will high temperatures across the interior Central Coast will be in the 80s to 90s. && .LONG TERM... (Wednesday night through next Monday) Issued at 207 PM PDT Tue Jun 10 2025 Temperatures remain fairly similar Wednesday through the weekend with highs in the 70s to low 80s across the interior Bay Area and 80s to low 90s across the interior Central Coast as zonal upper level flow persists. As zonal flow continues, we can expect to see similar stratus trends for much of this week with stratus returning during the evening and persisting into the next morning. Confidence is fairly high for coastal locations but slightly lower for locations across the interior where a deeper vs shallower marine layer will dictate how far inland stratus is able to extend. If the marine layer maintains a depth of around 2000 ft, stratus will extend farther across the interior. If the marine layer compresses to a depth of 1000-1500 ft, as guidance suggests is possible, stratus coverage may not extend across as much of the interior as it has over the past few days. Upper level ridging looks to briefly build late week, compressing the marine layer and warming temperatures by a few degrees, before a weak upper level trough moves through the Bay Area Sunday into Monday. This will help to decrease temperatures by 2-3 degrees across the interior from Sunday to Monday. The real question occurs just beyond the end of our forecast period with guidance split on if ridging will build over the West Coast next week or if zonal to weak upper level troughing will continue. The continuation of zonal flow to weak upper level troughing would not result in major changes to our current temperature forecast. However, if upper level ridging is able to setup temperatures are likely to see a warming trend next week. The 6 to 10 and 8 to 14 day outlooks from the CPC do support temperatures leaning above normal across the Bay Area and Central Coast from the middle to end of June. && .AVIATION... (18Z TAFS) Issued at 1146 AM PDT Tue Jun 10 2025 .AVIATION...The forecast will be the timing of the status of the stratus as the forecast has been and will be on repeat. Tended to trend with observations from today and yesterday for timing of arrival and departure respectively, assuming we have a similar marine layer depth. Expect IFR to MVFR cigs at most sites, with interior locations like KSJC and KLVK clearing the fastest, followed by North Bay terminals. IFR cigs may get low enough to drop vis MVFR at times. Vicinity of SFO...Medium to high confidence in the SFO forecast as the stratus pattern looks similar to what we saw yesterday, perhaps slightly stronger for stratus remaining socked in to the east at KOAK. Expect to have MVFR conditions hold through the period, with the chance for clouds becoming BKN for a period this afternoon. This will be short lived as the westerly feed of stratus is strong. Models generally struggle to capture this, with the HRRR, GLAMP, and NBM supporting this. Guidance seems supportive of potential clearing to some degree tomorrow afternoon between 18Z and 0Z. Though stratus looks to make yet another return after that. SFO Bridge Approach...The approach should fair better than the vicinity of SFO as we can see the stratus mixing out over the southern portion of the bay. The stratus line appears to be holding right around the vicinity given the continuous westerly flow. Expect similar conditions to yesterday where visuals will be short lived. Monterey Bay Terminals...Stratus will continue to hug the coast with clearing expected around Santa Cruz and the north part of the Bay. KSNS should see some clearing as well this afternoon based on persistence forecasting and satellite imagery. Unsure if MTR will be so lucky, opted to try and trend towards some VFR conditions with a TEMPO this afternoon. Otherwise expect MVFR to IFR cigs, and reduced vis with the low cigs. && .MARINE... (Today through Sunday) Issued at 238 AM PDT Tue Jun 10 2025 Fresh to strong northwesterly breezes will prevail through the forecast period with gale force gusts possible beginning Wednesday afternoon along the coastal jet regions of Point Reyes and Point Sur. Significant wave heights will be moderate today, building to become rough tomorrow. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 PM PDT Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm-SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PDT this evening for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory from 9 AM to 3 PM PDT Wednesday for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 3 PM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...KR 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