Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

951 pm PDT Tue Jun 30 2026

Short Term

, Issued at 1217 PM PDT Tue Jun 30 2026 (This evening through Wednesday night)

GOES-West visible imagery reveals the marine stratus blanketing much of the Pacific Coast from Sonoma south all the way through Monterey Counties. Communities inland, away from the influence of the stratus, are enjoying the abundance of June solar this afternoon with overall pleasant weather conditions. Temperatures this afternoon will max-out in the upper 50s to near 70 along the immediate Pacific coast, and warming to the 70s to 80s inland. Far interior locations in Contra Costa and Monterey Counties will flirt with the 90-degree mark. With these forecast highs generally running a few to several degrees below late June climatology, the HeatRisk today is solidly low to minor (green to yellow).

The main synoptic driver for the West Coast over the last several days has been a persistent long-wave trough that has sagged over the Rocky Mountains. This trough has brought unseasonably un- summerlike weather to parts of western North America. For us locally, the trough has helped reinforce the marine layer along the coast and as allowed for inland areas of California to remain comfortably cool for this time of year. The trough will hang around on Wednesday with similar temperatures for the coast while inland locations cool by a few more degrees.

Long Term

..issued at 1217 PM PDT Tue Jun 30 2026 (Thursday through next Monday)

The longwave trough will gradually weaken through second half of the week as zonal flow develops over the North Pacific. Temperatures will eventually respond to the rising heights with a gradual warming trend for central and northern California around Friday/Saturday. For those looking ahead to the holiday weekend, HeatRisk for the Bay Area and Central California Coast is forecast to remain low (green) along the immediate coast and minor (yellow) inland. Traveling for the holiday weekend? Even the typical heat-prone areas of California such as the Central Valley and deserts are only forecast to have minor (yellow) to moderate (Orange) HeatRisk.

Cluster analysis of the ensembles for next week are trying to pick-up on a West Coast ridge, but still observing many possible outcomes of varying strength and location. While the Climate Prediction Center does favor the likelihood of above- normal temperatures of us in the 8-14 day outlook (valid July 7-13), they do keep the slight risk of extreme heat to the east of the Bay Area, focusing on the Great Basin and Desert Southwest.

Aviation

(06z TAFS) Issued at 950 PM PDT Tue Jun 30 2026

MVFR CIGs last along the coast and around the Monterey Bay. The breezy winds across the area will reduce into the night, becoming light to moderate. CIGs fall to IFR levels in the late night at MRY and along portions of the immediate coast, with some IFR CIGs forming at APC. Cloud cover erodes at APC in the mid morning with other sites seeing clearing in the late morning and early afternoon, leading to widespread VFR. Winds build again into Wednesday afternoon, but only to moderate to breezy levels.

Vicinity of SFO, VFR through the TAF period. Breezy west winds reduce into the night, and become light by the early morning as scattered low clouds move through the area. Cloud cover thins into the mid morning as winds become more moderate. Expect winds to increase further in the mid afternoon, peaking around 16 kts before become light again into the night. Wednesday night stratus is expected to get close to SFO once again.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, MVFR CIGs continue to affect the terminals this evening. MRY CIGS looks to fall to IFR levels in the early morning as winds continue to reduce. CIGs erodes in the late morning and early afternoon around the Monterey Bay as moderate winds build. There is still some uncertainity on the clearing at the immediate coast, a repeat of Tuesday is still possible.

Marine

(tonight through next Monday) Issued at 950 PM PDT Tue Jun 30 2026

Strong northerly winds continue for the northern outer waters while weaker, yet still gusty winds affect the rest of the waters. Frequent gale force gusts are expected across the northern outer waters through Wednesday, a bit weaker winds for Thursday and Friday. Moderate northerly to westerly breezes will prevail elsewhere. Rough to very rough seas will continue through Wednesday before abating to become moderate to rough Thursday into Friday.

Watches, Warnings, Advisories

Ca, None. PZ, Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 9 AM PDT Wednesday for Pt Reyes to Pigeon Pt 0-10 nm.

Gale Warning until 3 AM PDT Thursday for Pt Arena to Pt Reyes 10- 60 NM.

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