Marine Weather and Tide Forecast for Cupertino, CA

UPDATE
Issued at 818 AM PDT Sat Apr 11 2026

The forecast remains on track this morning with no updates currently anticipated. While rain showers and a slight chance of thunderstorms will continue throughout the morning and early afternoon, the greatest threat will be late afternoon through late evening. This is as a narrow cold-frontal rainband is expected to approach the North Bay between 2 PM - 5 PM, 4 PM - 7 PM across the Bay Area, and 6 PM - 9 PM across the Central Coast. 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 remain in a Marginal Risk of severe thunderstorms. The greatest potential being the threat of southerly wind exceeding 40 knots over the ocean. Wind gusts are also expected to reach up to 50 mph along the coast and in the higher terrain during the aforementioned timeframes. Any stronger convection will be capable of producing stronger wind gusts.

RGass

SHORT TERM
Issued at 114 AM PDT Sat Apr 11 2026 (Today and tonight)

Convection for the Bay Area and Central Coast have eased and the atmosphere continues to stabilize and cool. Passing showers will continue through the night, but rainfall and localized winds look to be much more reasonable than the afternoon cells.

Shower activity reduces slightly into the late night, but widespread off and on showers are still expected. The warming from the sunrise and the warm sector of the next low pressure will increase mixing in the morning, leading to slight increases for more convective cells.
Storm chances will continue to build into the afternoon and look to hit their peak in the late afternoon and early evening. The near- coast marine environment shows around 35% chance for storms with 20 to 30% for areas overland.

These storm chances reduce as the next cold front moves through the area, with a fairly narrow and well-organized rain band moves through the region that evening and into the night. Southerly winds become gusty just head of the front peaking around 30 mph and some gusts around 45 mph will be possible, but luckily short-lived. Winds reduce quickly in the post frontal environment, but remain moderate to breezy through that night. Post-frontal showers and light chances for spotty storms will last through Saturday night. Additionally chances for flurries and possible dustings of snow will be possible

LONG TERM
Issued at 114 AM PDT Sat Apr 11 2026 (Sunday through Friday)

Chances for scattered storms increase again into Sunday as conditions warm into the afternoon. These chances may become a bit more limited due to the increasing cloud cover in the recent forecast updates and the overall colder flow entering the region, but will still be a possibility. Highs look to peak in the 50s and 60s for most areas on Sunday, with a few higher elevations failing to break 50. Shower and storm chances ease that night with some coastal drizzle possible into early Monday.

Overall remaining rain totals look impressive for this late in the season:

-Some of the higher coastal peaks are still looking at 2 inches of additional rainfall, even 3 in a few isolated area.

-Most of the North Bay is looking around an inch to 1.5" and around 2" in the interior mountains.

-The lower elevations around the the SF Bay and Monterey Bay will range from 0.75" to 1.10". Higher interior elevations 1.25" to 1.75"

-The lowest rainfall totals look to be the Southern Salinas Valley at 0.20" to 0.50"

Keep in mind, these totals could be massively affected by locally stronger storms, and the possibility of lines of showers and storms training over certain areas.

After the low pressure, storm environment, and the last few chances for precip exit, the forecast calms significantly. Temperatures warm slowly into the next work week, but with a fair amount of onshore flow keeping things seasonable. Longer term models show chances for another trough passing through in the late week, but some place it more inland. This difference in positioning can mean the difference between some drizzle and light rain, to increased offshore flow if the trough is more inland. So something to keep an eye on after all of the excitement this weekend.

AVIATION
(12Z TAFS)
Issued at 601 AM PDT Sat Apr 11 2026

Mostly light, scattered showers continue to move through the region.
Shower activity increases after sunrise with some spotty chances for passing storms. Lower cloud cover raises and scatters into the afternoon leading to widespread VFR, but with plenty of mid-level clouds. Southerly winds increase into the afternoon, ranging from 20 to 40 kt gusts across the region. Shower and storm chances increase in the late afternoon and into the evening ahead of a stronger rain band that will move through in the evening and early night. The moderate to heavy rain and stronger winds associated with this rain band will reduce visibilities. Winds and rain rates reduce behind this band, but breezy to gusty south to southwest winds last through much of Sunday morning. Showers become spotty into the night, but remain possible beyond the forecast period along with slight chances for storms.

Vicinity of SFO...Lower clouds linger into the mid morning before thinning and lifting. Winds become breezier and more southerly in the mid morning and become gusty into the afternoon with scattered showers and slight chances for storms increasing. The strongest winds arrive along the narrow cold front this evening, with the increase rainfall and winds reducing visibilities. Winds reduce slightly behind the main rain band and shower activity becomes scattered into the night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Light southerly winds and passing showers continue. Shower activity increases into the late morning with breezier winds building through the day. Spotty storm chances will be possible amongst the scattered showers. Higher and more widespread rains arrive along a narrow cold front in the late evening. This band of rain will offer gustier winds and reduced visibilities. Showers and slight chances for storms linger behind the front, with reducing winds into the night.

MARINE
(Today through Thursday)
Issued at 818 AM PDT Sat Apr 11 2026

Shower activity and chances for storms build into the afternoon.
A strong band of rain moves through Saturday evening and into that night. Expect gustier winds and rough seas, with isolated gale force gusts ahead and along this band of rain. Shower activity lingers behind the rain band, and picks up again into Sunday afternoon with chances for storms returning. Overall rain chances exit Sunday night. High pressure builds behind the system with fresh northwest winds developing early next week, as seas abate to become moderate through mid week.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory until 3 PM PDT Sunday for Mry Bay-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

Small Craft Advisory until 9 PM PDT this evening for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory from 3 PM this afternoon to 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM.