Port Costa, CA 94569 Weather

: New SHORT TERM, LONG TERM:

Key messages

Updated at 1213 PM PDT Fri Oct 30 2026

- Minor to moderate coastal flooding at high tide for Bayshore and Pacific Coast locations through the weekend

- Seasonal to slightly below seasonal temperatures through the extended forecast

- Potential for rain Saturday and again next week

Short term

Issued at 1213 PM PDT Fri Oct 30 2026 (This evening through Sunday)

There remains a slight chance to chance for rain showers across the Central Coast (mainly across interior Monterey County and San Benito County) through this evening. There is also a 5-10% probability of thunderstorms this afternoon and early evening across the mountains of San Benito County, however probabilities remain low at this time. The primary hazards with any isolated thunderstorms that do develop will be lightning, localized moderate/heavy downpours, and gusty/erratic winds.

Tonight, mostly dry conditions are forecast to persist as the cold front pushes into northern California and weakens as at approaches the Bay Area. This feature will bring chances for rain across the Bay Area by Saturday afternoon and into early Sunday morning. Meanwhile, chances for precipitation across the Central Coast from remnant moisture aimed toward southern California.

All that said, the NBM Probabilities of reaching greater than 0.25" (15-35%) reamin highest along the highest through tonight across Monterey and San Bentio. Then by Saturday night across Sonoma County and 15-45% across Monterey and San Benito counties Saturday night into Sunday morning.

From previous forecaster: "A combination of high astronomical tides and surge from thermal expansion and low pressure effects brings the risk of minor coastal flooding along the Bayshore at the San Pablo, San Francisco, and Monterey Bays, and the Pacific coast, at high tide today. At the San Francisco tidal gauge, high tide is expected to be 1.9 ft above normal (7.7 ft MLLW) at 2:39 PM today, 1.5 ft above normal (7.3 ft MLLW) at 3:44 PM Saturday, and 1.0 feet above normal (6.8 ft MLLW) at 3:59 PM Sunday, including around 1.5 ft of surge residual." The Coastal Flood Advisory drops off after high tide on Saturday for the Pacific Coast but remains in effect through Sunday for bayshore locations along the San Pablo, San Francisco, and Monterey Bays.

Long term

Issued at 1213 PM PDT Fri Oct 30 2026 (Sunday night through next Thursday)

Weak ridging builds in from the eastern Pacific Sunday and into Monday in wake of the exiting trough. This will result clearing of clouds regionwide and dry weather conditions Sunday afternoon through Monday afternoon along with a slight warming trend. However, temperatures will generally remain a few degrees below normal.

Tuesday and beyond, there is still a great amount of uncertainty with the forecast. The current forecast indicates a slight chance of rain/rain showers on Tuesday as a trough or cut-off low approaches the Bay Area and Central Coast. That said, the Climate Prediction Center's 6-10 Day Outlook our region in the 33-40% for greater than normal precipitation.

Aviation

(18Z TAFS) Issued at 1042 AM PDT Fri Oct 30 2026

VFR through the TAF cycle with some borderline VFR-MVFR ceilings possible Saturday morning at the Monterey Bay terminals. Gentle onshore breezes prevail through the afternoon gradually becoming light and variable overnight as the low pressure system nears our coastline. Scattered light rain associated with this system are likely to occur after the current TAF period beginning Saturday night.

Vicinity of SFO: VFR with some brief borderline MVFR-VFR ceilings possible this morning. Westerly breezes increase to around 10 kt this afternoon and gradually ease post-sunset while shifting southwest. A mixture of high to mid-level clouds are possible through the overnight hours. Onshore winds increase to 10 kt tomorrow afternoon with the potential for light rain to reach the terminal Saturday evening.

SFO Bridge Approach: Similar to SFO.

Monterey Bay Terminals: Mainly VFR through the TAF period with brief periods of borderline MVFR-VFR ceilings. Onshore winds increase up to 10 kt this afternoon and become light southwest to southerly breezes overnight. There is potential for some light drizzle Saturday morning, though confidence was too low to include in the TAF. Higher confidence for light rain to impact the terminal Saturday evening.

Marine

(Today through Wednesday) Issued at 906 AM PDT Fri Oct 30 2026

Gentle to fresh northwesterly breezes prevail with moderate seas through the weekend. A long period southwesterly swell combines with a long period west-northwest swell early next week.

Watches, warnings and advisories

CA: Coastal Flood Advisory until 6 PM PDT Sunday for CAZ006-506-508- 529-530.

Coastal Flood Advisory until 6 PM PDT Saturday for CAZ505-509.

PZ: None.