544 FXUS66 KMTR 120320 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 820 PM PDT Wed Jun 11 2025 ...New UPDATE... .SYNOPSIS... Issued at 301 PM PDT Wed Jun 11 2025 Stratus returns to portions of the Bay Area and Central Coast overnight with coastal drizzle likely tomorrow. Breezy afternoon onshore winds continue through the forecast period with highs lingering in the 70s to 80s and into the 90s across the far interior regions for much of the forecast period. && .UPDATE... Issued at 814 PM PDT Wed Jun 11 2025 Minor adjustments were made to the forecast to try and account for cloud cover. It should still be on track to expand into the Central Coast and Bay Area. && .SHORT TERM... (This evening through Thursday) Issued at 301 PM PDT Wed Jun 11 2025 Stratus has mostly receded offshore except along the coastlines of Marin and San Mateo Counties where some continues to linger. This retreat will be fairly short lived with stratus returning to portions of the Central Coast and Bay Area again this evening. The marine layer looks to remain around 2000 ft again tonight which would support stratus pushing into the Central Coast and San Francisco Bay shoreline region. However, cloud cover is expected to be slightly more limited tonight than it has been over the previous days with high resolution guidance keeping the North Bay clear tonight. One reason for this is that a weak passing shortwave trough allowed the marine layer to deepen to around 2300 ft last night (as seen on the 12Z OAK sounding this morning) which allowed stratus to penetrate deep into the Bay Area. This shortwave trough has since exited the region with more zonal flow returning as high pressure builds over the Intermountain West. In terms of stratus clearing, it has been trending slightly earlier in the morning each day this week. This same trend looks to hold true tomorrow with stratus to clear by mid to late morning across the region. This earlier clearing of stratus will help to increase confidence that sites will reach their forecasted high temperatures across the region. This is unlike Monday and Tuesday where prolonged stratus coverage decreased the amount of solar radiation able to reach the surface and kept temperatures much cooler than originally forecast. High temperatures on Thursday will be slightly warmer than those observed today with highs in the upper 70s to upper 80s across the interior and in the 60s to low 70s closer to the coastline. Breezy afternoon winds between 20 to 30 mph are expected across mountain gaps/passes and across the higher terrain this afternoon/evening and again Thursday afternoon/evening. Conditions are drying out across the interior which in combination with breezy afternoon/evening winds may result in an increased risk of grass fires - see Fires Section below - through the weekend. && .LONG TERM... (Thursday night through next Tuesday) Issued at 301 PM PDT Wed Jun 11 2025 Things remain fairly quiet through the extended with zonal flow to very weak ridging persisting Friday into the weekend. This will keep the forecast across the interior fairly similar to what we have already seen this week with highs in the 70s to low 80s and mid 60s to low 70s along the coastline. The interior Central Coast will remain warm through the weekend with highs in the 80s to low 90s. The main question continues to be the progression of a weak upper level trough (low pressure) through the Bay Area Sunday evening into Monday. Model guidance has slowed down the troughs arrival slightly and pushed into later into Monday with the trough exiting the region late Monday into early Tuesday. Cluster guidance does indicate a chance for the trough to persist through Tuesday but that scenario seems unlikely. Temperatures will remain in the upper 70s to low 80s across the interior on Monday before a warm up begins Tuesday with temperatures reaching into the upper 80s to low 90s. Diurnally breezy to gusty onshore winds continue across mountain gaps/passes, elevated terrain, and portions of the coastline through the end of the forecast period. Highest confidence is in gusts between 20 to 30 mph with funneling in gaps/passes potentially resulting in isolated stronger gusts. && .LONG TERM... (Thursday night through next Tuesday) Issued at 301 PM PDT Wed Jun 11 2025 Things remain fairly quiet through the extended with zonal flow to very weak ridging persisting Friday into the weekend. This will keep the forecast across the interior fairly similar to what we have already seen this week with highs in the 70s to low 80s and mid 60s to low 70s along the coastline. The interior Central Coast will remain warm through the weekend with highs in the 80s to low 90s. The main question continues to be the progression of a weak upper level trough (low pressure) through the Bay Area Sunday evening into Monday. Model guidance has slowed down the troughs arrival slightly and pushed into later into Monday with the trough exiting the region late Monday into early Tuesday. Cluster guidance does indicate a chance for the trough to persist through Tuesday but that scenario seems unlikely. Temperatures will remain in the upper 70s to low 80s across the interior on Monday before a warm up begins Tuesday with temperatures reaching into the upper 80s to low 90s. Diurnally breezy to gusty onshore winds continue across mountain gaps/passes, elevated terrain, and portions of the coastline through the end of the forecast period. Highest confidence is in gusts between 20 to 30 mph with funneling in gaps/passes potentially resulting in isolated stronger gusts. && .AVIATION... (00Z TAFS) Issued at 426 PM PDT Wed Jun 11 2025 MVFR-IFR stratus persists along the coast from Point Reyes southward to the San Mateo Peninsula, with scattered patches of stratus near the Monterey Peninsula and clear conditions everywhere else. Gusty onshore winds will continue through the evening hours, becoming light away from the immediate coast overnight. Stratus is expected to build inland south of the Golden Gate, with moderate confidence in a transitory ceiling at SJC and LVK on Thursday morning. Stratus will clear through Thursday morning and breezy winds will resume in the afternoon. Some high resolution models are even predicting that HAF may scatter out before the end of the 24-hour TAF period, although this is a low confidence forecast for the time being. Vicinity of SFO... MVFR ceilings have arrived at the terminal and will continue through the night, dipping to IFR later in the evening. Gusty west winds continue through the evening hours, with wind gusts up to 30 knots. Wind gusts over 35 knots are not expected for the rest of the day. Stratus will mix out Thursday morning. Strong and gusty west winds resume Thursday afternoon with a low probability (around 10-20%) for wind gusts over 35 knots. SFO Bridge Approach... The approach path remains clear with lower confidence for stratus impacts to the approach path overnight than over the terminal. Otherwise similar to SFO. Monterey Bay Terminals... VFR conditions along with breezy northwest winds continue through the next couple of hours. Monitoring scattered clouds over MRY for potential ceiling development earlier than the current forecast. IFR-LIFR ceilings then continue through the night before dissipating sometime Thursday morning. Moderate confidence in timing of clearing at MRY. Breezy onshore winds resume Thursday afternoon. && .MARINE... (Tonight through next Monday) Issued at 301 PM PDT Wed Jun 11 2025 Northwesterly winds will continue over the coastal waters heading into the weekend. Winds will increase Wednesday night leading to locally hazardous conditions with occasional gale force gusts developing near Point Reyes and south of Point Sur. Moderate to rough seas will prevail through the week. && .FIRE WEATHER... Issued at 301 PM PDT Wed Jun 11 2025 While the marine layer will remain in some capacity over the next few days, what happens above the marine layer is more of a fire weather concern. The last night or two have featured moderate to poor recoveries above the marine layer and that will continue Thursday night and Friday. In fact, some locations are hitting single digit and lower teens for RH values. Hi-res models even indicate a burst of NE flow late tonight into early Thursday over the N Bay. Not overly strong, but this will further enhance any drying. There is some quote, recovery, during the daytime, but another factor comes in. The breezy onshore flow. Winds will remain breezy each afternoon/evening through the Delta, and any inland gap or pass. The combination of dry fine fuels (grasses), lower RH, breezy winds with gusts in the 20-40 mph will elevate fire weather concerns. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Thursday for SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PDT this evening for Mry Bay. Small Craft Advisory until 9 AM PDT Friday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...DialH MARINE...MM 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