textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 107 PM PDT Thu Oct 29 2026

- Moderate coastal flooding at high tide for Bayshore and Pacific Coast locations through Friday; coastal flooding continues for Bayshore locations on Saturday

- Seasonal to slightly below normal temperatures through the extended forecast

- Potential for rain this weekend

UPDATE

Issued at 904 PM PDT Thu Oct 29 2026

Satellite imagery is showing a pretty robust stream of high clouds stemming from the remnants of a low from the Central Pacific merging into a wider trough pattern across the West Coast, with some of the embedded moisture creating some rather cool cloud tops on satellite and echoes from the KMUX radar. Several stations within the Big Sur coastal region and the Santa Lucia range have reported measurable rainfall over the last couple of hours, and chances for showers have been added to the forecast for Monterey and San Benito Counties through the rest of the night into Friday morning, although it does look like we are on the back end of the shower potential tonight. The rest of the forecast is unchanged.

DialH

LONG TERM

Issued at 107 PM PDT Thu Oct 29 2026 (Saturday through next Wednesday)

Upper level troughing will become more pronounced across the West Coast Saturday and Sunday. Guidance shows a few areas of weak low pressure developing offshore of the PNW and offshore of Northern California. A slightly stronger area of low pressure is located to the southwest of Southern California and will strengthen into a weak low pressure system as it moves towards the California-Mexico border. This system is associated with a much more impressive moisture transport that will move into Southern California with the tail edge of the moisture just tapping the Central Coast and Bay Area. The current forecast shows minimal rain across our forecast area with only a few hundredths of an inch expected. The exception would be the North Bay Coastal Mountains and the interior Central Coast where between a tenth to a quarter of an inch is expected. For the North Bay Coastal Mountains, orographic uplift is likely responsible for the slightly higher totals. The Interior Central Coast benefits both from orographic uplift along the Gabilan range and from being closer to the primary moisture plume over Southern California. The previous shift noted that precipitation values for this weekend have been flipping around which is still partially true. Up until this morning's forecast update, the values had been trending downwards. However, models are now keying in on the moisture plume spreading more northwards and ensembles show the potential for a trace of rain to a tenth of an inch. This is consistent with the current forecast and there is good consensus between the ECMWF and GFS that precipitation will be light. Showers are likely to develop early Saturday morning across the interior Central Coast and spread northwards into the Bay Area by late Saturday. Light rain/drizzle may start during prime Trick or Treating hours but the highest chances for precipitation will fall after midnight/early Sunday morning. There is a low (< 15%) chance of thunderstorms on Saturday/Sunday as this system moves through. The overall environment looks fairly marginal but the upper level low is transporting a cold enough airmass in that it may be enough to bring localized thunderstorms to the higher elevations. The best potential is over the marine environment and along the coastline with much lower chances across the interior.

Below normal temperatures continue this weekend into next week as the upper level trough brings another round of much colder air into the region. The 850 mb temperature looks to drop to between 4-6 C this weekend which is below the 25% percentile of 850 mb temperatures for late October. As a result, high temperatures will be well below average on Saturday in the upper 50s to low 60s. We can expect temperatures to gradually warm up heading into next week as the trough moves out and upper level ridging rebuilds across the region. This would see temperatures warming back into the upper 60s to low 70s across the interior while coastal areas stay in the upper 50s to 60s. The most recent forecast update has pushed our next rain episode back from mid next week to late next week. Ridging is now expected to persist through the first part of the week with the next trough not set to arrive until Wednesday/Thursday. It's too far out to talk about rain totals for this event but it will definitely be something to keep an eye on.

Coastal flooding concerns continue across Bayshore locations within the San Pablo, San Francisco, and Monterey Bays through Saturday. At the San Francisco tidal gauge, high tide is expected to be 1.1 feet above normal (6.9 ft MLLW) at 03:44 PM on Saturday 10/31.

LONG TERM

Issued at 107 PM PDT Thu Oct 29 2026 (Saturday through next Wednesday)

Upper level troughing will become more pronounced across the West Coast Saturday and Sunday. Guidance shows a few areas of weak low pressure developing offshore of the PNW and offshore of Northern California. A slightly stronger area of low pressure is located to the southwest of Southern California and will strengthen into a weak low pressure system as it moves towards the California-Mexico border. This system is associated with a much more impressive moisture transport that will move into Southern California with the tail edge of the moisture just tapping the Central Coast and Bay Area. The current forecast shows minimal rain across our forecast area with only a few hundredths of an inch expected. The exception would be the North Bay Coastal Mountains and the interior Central Coast where between a tenth to a quarter of an inch is expected. For the North Bay Coastal Mountains, orographic uplift is likely responsible for the slightly higher totals. The Interior Central Coast benefits both from orographic uplift along the Gabilan range and from being closer to the primary moisture plume over Southern California. The previous shift noted that precipitation values for this weekend have been flipping around which is still partially true. Up until this morning's forecast update, the values had been trending downwards. However, models are now keying in on the moisture plume spreading more northwards and ensembles show the potential for a trace of rain to a tenth of an inch. This is consistent with the current forecast and there is good consensus between the ECMWF and GFS that precipitation will be light. Showers are likely to develop early Saturday morning across the interior Central Coast and spread northwards into the Bay Area by late Saturday. Light rain/drizzle may start during prime Trick or Treating hours but the highest chances for precipitation will fall after midnight/early Sunday morning. There is a low (< 15%) chance of thunderstorms on Saturday/Sunday as this system moves through. The overall environment looks fairly marginal but the upper level low is transporting a cold enough airmass in that it may be enough to bring localized thunderstorms to the higher elevations. The best potential is over the marine environment and along the coastline with much lower chances across the interior.

Below normal temperatures continue this weekend into next week as the upper level trough brings another round of much colder air into the region. The 850 mb temperature looks to drop to between 4-6 C this weekend which is below the 25% percentile of 850 mb temperatures for late October. As a result, high temperatures will be well below average on Saturday in the upper 50s to low 60s. We can expect temperatures to gradually warm up heading into next week as the trough moves out and upper level ridging rebuilds across the region. This would see temperatures warming back into the upper 60s to low 70s across the interior while coastal areas stay in the upper 50s to 60s. The most recent forecast update has pushed our next rain episode back from mid next week to late next week. Ridging is now expected to persist through the first part of the week with the next trough not set to arrive until Wednesday/Thursday. It's too far out to talk about rain totals for this event but it will definitely be something to keep an eye on.

Coastal flooding concerns continue across Bayshore locations within the San Pablo, San Francisco, and Monterey Bays through Saturday. At the San Francisco tidal gauge, high tide is expected to be 1.1 feet above normal (6.9 ft MLLW) at 03:44 PM on Saturday 10/31.

AVIATION

(06Z TAFS) Issued at 938 PM PDT Thu Oct 29 2026

Not much has changed from 00Z TAFs - VFR conditions will be common place through much of Friday with mid-high level clouds. MRY and SNS may have a passing showers or two lowering cigs below 5k. Better chc for CIGs late Friday into Saturday.

Vicinity of SFO...VFR. Light and vrb near term, but do expect an onshore push by this evening.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...VFR. Brief MVFR this evening then better chc for MVFR CIGs Friday. Diurnal drainage overnight and then onshore during the day.

MARINE

(Today through Tuesday) Issued at 1044 AM PDT Thu Oct 29 2026

Conditions gradually improve through the day with strong northwest breezes becoming fresh to moderate with rough seas improving as well. Improving conditions will continue into the weekend while a long period west-northwest swell arrives this weekend and continues into next week.

MTR WATCHES/WARNINGS/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...Small Craft Advisory until 6 PM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.