Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

431 pm PDT Fri aug 7 2026

Short Term

, Issued at 1211 PM PDT Fri Aug 7 2026 (This evening through Sunday night)

The warming trend will begin today and persist through the weekend as high pressure over the Desert Southwest builds westward. Thus, Heat Advisories remain in effect for all of the Interior Bay Area and Central Coast from 10 AM Saturday through 10 PM Sunday. The exception is the North Bay Valleys where we have temperatures forecast to be in the mid 80s to mid 90s. However, places such as Cloverdale is forecast to be the hottest and are expected to exceed 100 deg F. Temperatures under the Heat Advisory are forecast to warm into the mid 90s and up to 105 deg F in the warmest interior locations where the most widespread moderate to isolated major HeatRisk are present. Overnight lows are also forecast to be warm in the mid 60s in the hills just above the marine influences to low 80s (especially in the higher elevations). Maximum temperatures closer to the coast are forecast to be in the 60s to mid 70s thanks to the continued onshore flow and marine influences. Overnight lows near the coast are largely forecast to be in the 50s over the weekend.

During this weekends heat event, remember:

* Stay hydrated and drink plenty of fluids. * Wear lightweight and light-colored clothing. * Reduce time spent outdoors or stay in the shade. * Never leave people or pets unattended in vehicles. * Use sunscreen if going to the coast or the pool.

Minor coastal flooding is also expected at the time of peak high tide (evening/overnight) for bayshore locations along the San Francisco, San Pablo, and Monterey Bays this evening through next Thursday morning. Please see the CFW product we have out for additional details.

Long Term

..issued at 1211 PM PDT Fri Aug 7 2026 (Monday through next Thursday)

Temperatures begin a cooling trend on Monday as the ridge starts to flatten, yet the interior will still be quite warm. Northerly winds are forecast to increase and will result in hazardous conditions to small craft early next week as well, especially across the northern waters. Temperatures are then forecast to cool to below seasonal averages late next week as troughing develops off of the West Coast.

Aviation

(00z TAFS) Issued at 431 PM PDT Fri Aug 7 2026

Patchy MVFR-IFR stratus lingers at the immediate coast with high clouds over portions of the North Bay and the San Mateo Peninsula. Breezy and gusty onshore pattern winds continue into the evening hours. Overnight, stratus will gradually expand inland, with moderate to high confidence that the marine layer will compress as an upper level ridge builds over the region. If this compression does not occur, SJC could receive an MVFR ceiling early Saturday morning. Stratus will retreat to the immediate coast through Saturday morning with breezy onshore winds resuming in the afternoon.

Vicinity of SFO, VFR through the evening hours with moderate and gusty northwest winds. Moderate confidence that a ceiling will develop over the terminal early Saturday morning, with some high resolution model output depicting the stratus deck deflected to the north of the terminal. Stratus dissipates over the post-sunrise hours and breezy west-northwest winds develop Saturday afternoon.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, VFR conditions continue for a couple of hours before IFR-LIFR stratus moves over the terminals early this evening, dissipating through the course of Saturday afternoon. Breezy northwest winds will diminish this evening and resume Saturday afternoon.

Marine

(tonight through next Wednesday) Issued at 431 PM PDT Fri Aug 7 2026

Moderate northwest seas gradually build to rough (9-12 feet) as northwest winds increase to fresh to strong by Saturday. Seas and winds remain elevated through the middle of next week. Embedded near gale force gusts are possible across the outer northern coastal waters. A long period southerly swell (15 to 17 seconds) persists through the weekend.

Watches, Warnings, Advisories

Ca, Coastal Flood Advisory until 2 AM PDT Thursday for CAZ006-506- 508-529-530.

Heat Advisory from 10 AM Saturday to 10 PM PDT Sunday for CAZ503- 504-510-512>518.

PZ, Small Craft Advisory from 3 PM Saturday to 9 AM PDT Sunday for Pt Arena to Pt Reyes 10-60 NM.

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