939 FXUS66 KMTR 011824 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1124 AM PDT Sun Jun 1 2025 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 912 AM PDT Sun Jun 1 2025 Cooling trend for inland areas today as onshore winds return to the region. A seasonal weather pattern is forecast for the upcoming week with near normal temperatures, dry conditions and breezy onshore winds, strongest during the afternoon and evening hours. && .UPDATE... Issued at 912 AM PDT Sun Jun 1 2025 Visible satellite shows morning low clouds hugging the coastline and pushing into SF bay with an inversion depth around 1500 feet. Otherwise a sunny start for much of the interior North/South and East Bay. Morning temps already running as much about 10 degrees cooler than yesterday morning for places like Livermore thanks to increasing onshore pressure gradient of 3.3 mb SFO-Sac, strong for this early in the morning. Upper level disturbance will drop down the coast later today into tonight. 12z model guidance keeps instability to a minimum with very dry atmospheric profile, thus chance of any rogue thunderstorms for our CWA looks to be less than 5%. Some breezy northerly wind work down the Sac Valley tonight and will skirt into the Napa hills late tonight into Monday morning. However fire weather concerns remain minimal as RH recovery will be moderate to good. That shortwave pushes into SoCal by Tuesday setting up a week of seasonal and dry weather with temps mainly 60s coast, 70s bayside and 80s inland. && .SHORT TERM... (Today and tonight) Issued at 305 AM PDT Sun Jun 1 2025 Key Messages -Pattern change and cool down today Upper level troughing to our northwest will continue to deepen today and enter northern CA while the cutoff low to the west of Baja California drifts north and eastward. These systems will continue to cut off our access to high pressure, leading to cooler weather spreading over the region. Interior locations for the North Bay and Central Coast will remain near normal for this time of year, where highs will span the 80s. Elsewhere near normal to below normal temperatures are expected as temperatures range from the mid 50s to low 70s, with it being warmer as you go inland. && .LONG TERM... (Monday through Saturday) Issued at 305 AM PDT Sun Jun 1 2025 Key Messages -Marine layer returns, more seasonal weather by mid to late week -Small warm up possible by next weekend The trough entering into northern CA on Sunday is forecast to become a cutoff low late Sunday night into early Monday morning. This system is expected to gradually slide down the CA coast on Monday, making it to southern CA by Tuesday. As it does this, the cutoff low from Baja gets ejected into the Desert Southwest. Cooler weather remains in the forecast during this time frame, with the marine layer making a return Sunday night into Monday morning. There is some uncertainty as to how late Monday into Tuesday looks. Some models try to spin a ribbon of moisture up into our next of the woods as the low traverses south. Additionally some models throw some instability into this mix, which support isolated thunderstorms. Confidence remains low to add thunderstorms to the forecast at this point. There`s a better chance of seeing fair weather cu develop over our area rather than thunderstorms at this time. Will need to keep an eye out on the forecast to see if any additional CAMs tap into this solution. Cooler to near seasonal weather is on tap through at least midweek. We could see a small warm up by next weekend. && .AVIATION... (18Z TAFS) Issued at 1124 AM PDT Sun Jun 1 2025 Cloud cover is eroding for all but the immediate coast, but CIGs look to clear or at least scatter for all of the TAF sites by the mid afternoon. Expect moderate to breezy winds through the afternoon and into the evening. CIGs rebuild in the early evening along the coast, the SF Bay and for the Monterey Bay, but coverage will be spotty. More consistent MVFR CIGs affect the Monterey Bay terminals into the night as winds reduce across the region, while cloud cover retreats around the SF Bay. A surface low nears the region in the late night and early morning, leading to some pronounced wind shifts and reversals for sites closer to the coast. It will also pull cloud cover away from the coast, leading a reduction in CIGs at HAF, and Mid-morning clearing for the Monterey Bay. Inconsistent IFR CIGs also look to affect APC in the late night and into the early morning before eroding. Moderate winds and Widespread VFR is expected by late Monday morning Vicinity of SFO...Expect VFR to last into the late evening. Breezy to gusty west winds last into the late evening before reducing as scattered low clouds build around the SF Bay. These clouds look to inconsistently fill over SFO and OAK into the first part of the night before retreating. Winds stay light until the mid morning before becoming more moderate and northeasterly, but then switch back to being westerly into Monday afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Cloud cover scatterers into the afternoon as winds increase. Expect winds to reduce again into the evening as cloud cover begins to rebuild. An otter eddy looks to form in the center of the Monterey Bay in the early evening, causing cloud cover to inconsistently fill over the terminals through the evening and into the night. CIGs become more consistent into the late night with winds reducing further. A surface low moves into the area and just west of the Monterey Bay into mid Monday morning. This will pull cloud cover away from the terminals before the end of the TAF period. && .MARINE... (Today through Friday) Issued at 1124 AM PDT Sun Jun 1 2025 The outer waters continue to see strong to gale force gusts continue across the outer waters and these winds look to last into early work week. The strongest winds will be over the far northern outer waters where occasional storm force gusts will be possible from Point Arena to Point Reyes. Rough seas continue over the outer waters with significant wave heights building to 10 to 15 feet across the southern outer waters and up to 22 feet across the northern outer waters Sunday evening into Monday morning. Winds gradually ease by Tuesday but significant wave heights will remain elevated through late next week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Monday for SF Bay N of Bay Bridge. Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 0-10 nm. Gale Warning from 3 PM this afternoon to 3 AM PDT Monday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 9 PM PDT this evening for Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning until 9 AM PDT Monday for Pt Arena to Pt Reyes 10- 60 NM. Small Craft Advisory until 3 PM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...KR LONG TERM....KR AVIATION...Murdock MARINE...Murdock 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