Marine Weather and Tide Forecast for Daly City, CA

UPDATE
Issued at 910 PM PDT Tue Oct 15 2024

Not much to update from the previous discussion. Models and ensemble members continue to increase confidence in significant offshore winds in the second half of the work week. Winds are also looking to be strong over the ocean, leading to aggressive ocean hazards with gale-force to storm-force marine wind thresholds possible.

-Murdock

SHORT TERM
(This evening through Wednesday)
Issued at 114 PM PDT Tue Oct 15 2024

Mild and fairly quiet conditions continue through the middle of the week. A shortwave trough out ahead of the main upper low is progged to move across the region Wednesday morning, which will result in a slight chance of drizzle across the Bay Area, North Bay, and coastal areas. A few lucky locations in the North Bay and around San Francisco may see a passing light shower through midday Wednesday, but most places are not expected to see much in the way of beneficial wetting rain.

LONG TERM
(Wednesday night through next Monday)
Issued at 114 PM PDT Tue Oct 15 2024

Thursday is the transition day where things start to become more interesting. Following the passage of the weak shortwave Wednesday, a deep upper low is progged to move into the Great Basin from the northwest. Winds are set to increase as the surface front approaches through the day Thursday, but humidity will remain relatively high as winds will be out of the northwest initially. By Thursday evening, the rather vigorous trough axis sweeps through the state by around sunset, which is when we should see a more substantial increase in winds. Strong surface high pressure will quickly build in the wake of the front overnight Thursday, promoting a more north-northeasterly wind component.
This will be the defining moment when humidities will start to drop quickly to critical levels through Friday morning. The offshore-oriented pressure gradient from Redding to Sacramento is expected to peak Friday morning near the 99th percentile, further bolstering confidence in a potentially high impact event for the North Bay interior mountains. On a more broad scale, the pressure gradient from San Francisco to Winnemucca is forecast to be offshore-oriented from Friday morning until Saturday night, peaking around Friday afternoon. Nothing particularly notable on the extreme scale, but there is reasonable agreement among guidance...once again increasing the confidence in the large scale impact of this offshore wind event. As it stands with current guidance, the most worrisome areas are likely to be the North Bay interior mountains, the East Bay hills and Diablo Range, and the SF Peninsula. Higher terrain and ridges will be especially vulnerable, with gusts up to 65 mph possible. Otherwise, winds will be in the 25-35 mph range, with gusts to 45. The offshore gradient weakens and order is restored by late Saturday into Sunday as the upper low weakens and moves inland.

AVIATION
(06Z TAFS)
Issued at 1031 PM PDT Tue Oct 15 2024

The tail end of a cold front is approaching the North Bay tonight and may bring a few rain drops over the next 24 hours. The main effects on aviation weather will be the increased mid and high cloud coverage and a deepening marine layer in response to the lower atmospheric pressure. Despite the increasing cloud cover, the deeper marine layer should result in less ceiling and visibility issues as compared to last night. The front likely won't make it to the southern terminals before LIFR ceilings roll in overnight, however.

Vicinity of SFO...VFR expected through the TAF period, but there is an increasing chance of a sunrise surprise, with IFR ceilings possible between 12 and 18Z. Otherwise standard onshore winds are expected to pick up in the afternoon. Looking ahead, much stronger winds are expected Thursday evening, which may trigger an airport weather warning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Clear skies at the moment, but the night fog imagery is showing increasing low cloud cover building at both MRY and SNS. Expect IFR-LIFR ceilings to dominate after midnight (07Z). Otherwise mid and high cloud coverage will arrive as the low clouds clear midday.

MARINE
(Tonight through next Monday)
Issued at 910 PM PDT Tue Oct 15 2024

Rough seas continue to diminish across the outer waters with fresh to moderate NW breeze. Conditions will gradually improve through early Wednesday as the long period swell abates but this reprieve will be short lived as conditions deteriorate again by Wednesday night. Gusty winds will start to increase and will become hazardous into Friday, with the potential for gale and possible storm force winds.

FIRE WEATHER
Issued at 149 AM PDT Tue Oct 15 2024

A Fire Weather Watch is in effect from 11 AM Thursday until 8 PM Saturday. Normal temperatures, excellent relative humidity recoveries, and onshore flow will keep fire weather concerns at ease through Wednesday. Fire weather concerns will be high Thursday through the weekend as an inside slider event comes to town. While fuels are near average, they are expected to dry out as the week progresses. Northerly winds will develop Thursday as a deep upper-level low digs into the Great Basin. As this digs further south and becomes a cutoff low, winds will become northeasterly/offshore. These winds will lead to rapid drying, compressional warming, poor relative humidity recovery and retention as low as 15%, and a nonexistent marine layer. The windiest timeframes will be Thursday night into Friday morning and Friday night into Saturday morning with winds largely on the order of 20-30 mph with gusts to 40 mph, isolated gusts to 50 mph across the highest terrain and ridgetops and through gaps and passes.

BEACHES
Issued at 1050 AM PDT Tue Oct 15 2024

Long period northwesterly swell of 13-17 seconds with wave heights approaching 10 feet will result in a moderate risk of sneaker waves across all Pacific Coast beaches through at least Wednesday. Large waves can sweep across the beach without warning, pulling people into the sea from rocks, jetties, and beaches. Beachgoers should always remember to observe the ocean for 20 minutes before relaxing near the water, keep your pets on a leash and away from the water, and never turn your back on the ocean.

MTR WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement through Wednesday evening for CAZ006-505- 509-529-530.

Red Flag Warning from 11 PM Thursday to 5 PM PDT Saturday for CAZ006-502>504-506-508>510-512>518-528.

PZ...Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Mry Bay.

Small Craft Advisory from 9 AM Wednesday to 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory from 3 PM Wednesday to 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10- 60 NM-Pt Reyes to Pigeon Pt 0-10 nm.

Gale Watch from Thursday afternoon through Thursday evening for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 3 AM PDT Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.