Marine Weather and Tide Forecast for San Francisco, CA

SHORT TERM
Issued at 1220 PM PDT Fri Apr 10 2026 (This evening through Saturday)

A mid/upper level low pressure system remains about 100 miles off of the northern California coast. This feature has resulted in widespread rain showers across our region the past 24 hours with the North Bay picking up between 0.25"-1.25". Lesser amounts have been reported south of the North Bay, but some coastal and mountain locations have received up to 0.75". Overall, this has been greater than originally forecasted. This band of rain showers continues to shift inland and the threat for rain showers and thunderstorms will persist throughout the afternoon and evening, especially as day time heating increases surface based CAPE to between 500-1000 J/kg. Any thunderstorm will be capable of producing lightning, locally heavy rainfall, erratic/gusty winds, and small hail. Weak low-level wind shear does not support a mention of rotation that would lead to tornadoes and/or waterspouts through this evening. Rain showers and a slight chance of thunderstorms will continue into the night, yet chances for both trend downward overnight.

An approaching mid/upper level low is forecast to drop out of the Gulf of Alaska on Saturday and move inland Sunday afternoon across northern California. This is when we have all three ingredients for thunderstorms: lift, instability, and moisture. Some of the higher resolution and conviction-allowing models (CAMs) such as the RRFS indicate the potential for a narrow cold-frontal rainband (NCFR) to move across the Bay Area and Central Coast Saturday afternoon and evening. This will be when we have the greatest potential for rotating cells that may produce waterspouts and/or weak tornadoes.
In coordination with the Storm Prediction Center, we have been upgraded to a Marginal Risk of severe thunderstorms on Saturday. The greatest potential being the threat of wind exceeding 40 knots.

From previous forecaster: "Anglers should take special note of the expected weather and have a plan to reach safe harbor quickly when the weather turns. Even without thunderstorms, the marine conditions will deteriorate through the day Saturday. If thunderstorms develop, the associated wind gusts are capable of capsizing small vessels.
Fishing leads to more lightning deaths in the U.S. than any other activity. When thunder roars, head indoors!"

LONG TERM
Issued at 1220 PM PDT Fri Apr 10 2026 (Saturday night through next Thursday)

The rainfall amounts continue to trend higher today through Sunday with 0.50"-0.75" in the southern Salinas Valley, 1"-2" across much of the Bay Area and Central Coast, and up locally up to 4" in the coastal ranges. However, this rainfall will be mostly beneficial with no widespread river flooding anticipated. However, we can still see ponding of water on roadways, minor urban and small stream flooding, and flooding of poorly drained areas. This will be especially so if any heavier showers and/or thunderstorms develop and train over any one given area.

Post-frontal rain showers and isolated thunderstorm will continue into Sunday as a colder air mass settles into the region. This is when we may see snow fall across the higher peaks across the region, however little to no snow accumulation is expected. Lingering rain showers and isolated thunderstorms may persist into early Monday morning before a warming and drying trend resumes by Monday afternoon. Slightly below normal temperatures are expected Monday afternoon before rebounding to near seasonal averages by Thursday and Friday.

AVIATION
(18Z TAFS)
Issued at 1230 PM PDT Fri Apr 10 2026

It's a challenging day for TAFs, as we have scattered showers moving through the region leaving mix of IFR to VFR ceilings and visibility. Expect skies to remain partly to mostly cloud for the next few hours, with perhaps some clearing this afternoon. Given the lingering moisture and the potential for some sunshine there may be a renewed push for isolated to scattered showers this afternoon and evening. The big question will be thunderstorm chances. The SPC mesoanalysis page currently shows decent surface CAPE, around 500- 1000 J/kg, low level lapse rates around 6.5-7.5 C/km, and LI's around 0 to -1. In terms of shear, aka as lift, we currently have around 20-30kt. This would support thunderstorm potential if conditions continue to hold or continue to become more favorable for development. For now, there is no mention of VCTS or TS in the TAFs, excluding LVK, but my current thinking is that timing would look to be between 20-3Z for Bay Area terminals. Here the chance of thunderstorms range from 30-50%, favoring the interior North and East Bay areas.

Vicinity of SFO...VFR to MVFR conditions are forecast this afternoon and evening due to lingering clouds and showers moving through the region. As noted above conditions are becoming favorable for thunderstorms. KSFO has the about a 30-40% chance for thunderstorms from 18-0Z this afternoon with chances falling to 15-20% until 3-4Z.
For now, there is no mention of VCTS or TS/TSRA in the TAF, but it will be something to monitor this afternoon and evening. After that, there might be some showers that pass through tonight and into tomorrow morning. Winds begin to increase tomorrow afternoon and into the evening, as the next storm system arrives. 20-25kt gusts are possible from 21-0Z on Saturday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...A mix of sun and clouds should lead to VFR conditions through the afternoon. Showers, roughly a 20-30% chance, and perhaps a rogue thunderstorm, around 15-20%, will be possible through 0Z. The forecast becomes tricky once again, with models showing additional rounds of -SHRA or VCSH this evening and into the early overnight hours. MVFR cigs would be expected with these conditions, but also have the potential to occur without rain.

MARINE
(Tonight through next Wednesday)
Issued at 1220 PM PDT Fri Apr 10 2026

Isolated to scattered showers and a chance of thunderstorms remain in the forecast today. The next round of precipitation arrives late Saturday into Sunday, as the next weather system arrives. Increasing winds are expected, with isolated gale force gusts from Pigeon Point to Point Pinos. High pressure builds behind the system with fresh northwest winds developing early next week.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory from 9 AM to 9 PM PDT Saturday for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory from 3 PM to 9 PM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM.