Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

852 pm PDT Sat Jun 20 2026

Short Term

, Issued at 109 PM PDT Sat Jun 20 2026 (This evening through Sunday)

What a difference 24 hr makes, warmer conditions and increased sunshine. Afternoon visible satellite shows a well defined circulation spinning off the Central Coast. The nearby circulation, weaker marine layer inversion, and departing upper level trough led to increased sunshine along the coast and earlier clearing of AM clouds.

The rest of the weekend will feature rather nice sensible weather. Not a bad Father's Day weather wise. A weak shortwave upper level ridge will nose in late tonight and Sunday. The marine layer won't completely go away tonight, but it will be slightly more compressed due to building 500mb heights. Even with it being more compressed we will still a solid inland intrusion with clouds covering much of the inland valleys. Morning marine layer will roll back to the coast mid-morning, but coastal areas may struggle to get any clearing tomorrow. Away from the coast temps will climb a few more degrees with highs in the 70s to mid 80s.

Long Term

..issued at 109 PM PDT Sat Jun 20 2026 (Sunday night through next Friday)

Long range forecast remains on track with the evolution of the longwave pattern. The large upper level area of high pressure over the Desert SW/N Mexico will strengthen and nudge northward. The building high will continue to compress the marine layer and continue the warming and drying trend. At this point the two warmest days appear to be Tuesday/Wednesday with highs 60s/70s coast/bays and 80s/upper 90s interior. The warming trend will also cause an uptick in HeatRisk back into Moderate category. Coverage of Moderate HeatRisk does not seem widespread enough to warrant a Heat Advisory at this point, but we'll be messaging heat impacts regardless. To round out the rest of the work week temperatures begin to moderate and then cool.

Previous discussions mentioned low chance high impact thunderstorm scenario next week, but latest model trends show this being less likely. Longer range guidance still shows a surge of higher PWATs moving north along Baja, but instead of continuing north they drift more NE. We'll still monitor, but chance for thunder is looking less.

Aviation

(06z TAFS) Issued at 852 PM PDT Sat Jun 20 2026

VFR conditions prevail due to carryover mixing within the boundary layer from earlier in the day. A shallow cool front will move southeastward along the CA coast, combining with post sunset radiative cooling this will bring a return of stratus /MVFR-IFR/ tonight and Sunday morning. Thermal ridging will persist aloft during the period. Patchy light coastal drizzle is possible tonight and Sunday morning. Coastal stratus mixes out to MVFR-VFR late Sunday morning and afternoon. Coastal stratus redevelops Sunday night and Monday morning.

Vicinity of SFO, Stratus /MVFR/ is forecast to return to the terminal. Stratus /MVFR/ and tempo light drizzle tonight and Sunday morning. Conditions improve to VFR by 18z Sunday. Stratus /MVFR/ returns by mid Sunday evening. West wind 11 to 18 knots due to the incoming cool front tonight. West wind 15 to 25 knots redeveloping by 21z Sunday afternoon, easing to near 10 knots mid Sunday evening.

SFO Bridge Approach, Similar to SFO.

Vicinity of SJC and OAK, For SJC Airport VFR for the evening, stratus /MVFR/ returns by 10z then mixes out to VFR by 18z Sunday. Northwest wind 10 knots tonight becoming light southeasterly Sunday morning. Northwest wind redeveloping Sunday afternoon. For OAK Airport stratus /MVFR/ prevails tonight and Sunday morning, mixing out to VFR by 18z. Also, tempo light drizzle 11z-15z Sunday. West wind 5 to 15 knots.

Monterey Bay Terminals, Stratus /MVFR/ returns this evening, stratus prevails with tempo light drizzle tonight and Sunday morning. Conditions improving to VFR late Sunday morning and afternoon. Stratus /MVFR-IFR/ returns Sunday evening and night. Onshore winds 5 to 15 knots.

Marine

(tonight through next Friday) Issued at 843 PM PDT Sat Jun 20 2026

Fresh to strong winds in the northern outer waters now through early Monday morning, leading to hazardous conditions for small craft. Otherwise, across the inner and outer waters winds will remain light to moderate. Long period southwest swell continues through the forecast period.

Beaches

Issued at 308 AM PDT Sat Jun 20 2026

Long period southerly swell at around 15 to 17 seconds will persist for the remainder of the weekend, and increase to 17 to 19 seconds by the middle of the upcoming work week as energetic storms in the Southern Hemisphere continue to affect the California coast, especially for south and southwest facing beaches. Hazardous beach conditions are advertised, specifically for moderate to steeply sloped beaches along the Pacific Coast of the North Bay, San Mateo, Santa Cruz counties. A Beach Hazards Statement for Pacific Coast beaches continues through Wednesday afternoon. Be sure to check beach conditions before you head out. Sneaker waves will run up the beach much farther than other waves, potentially catching beachgoers by surprise and resulting in people being swept into the water. Rip currents are strong enough to pull the strongest swimmers away from shore. Swim near a lifeguard if possible. Stay back from the beach, and away from jetties, piers, beachside rocks, and other infrastructure near the water. Never turn your back to the ocean!

Watches, Warnings, Advisories

Ca, Beach Hazards Statement through Wednesday afternoon for CAZ006- 505-509-529-530.

PZ, Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.

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