UPDATE
Issued at 850 PM PDT Sun Oct 13 2024

The forecast remains on track. A robust marine layer has seen low stratus filling in across our coastal locations, and into the normal gaps and valleys. Along with the low stratus expect some patchy fog and periods of light drizzle to continue through the overnight into mid/late morning tomorrow. Once the stratus clears, expect marginally warmer temperatures the next couple of days. A slight chance of light rain remains in the forecast across the North Bay for late Tuesday night through Wednesday morning, however forecast trends have been drier for the remainder of our area south of there. By Thursday, a strong cold front will bring gusty winds and a dry airmass with critical fire weather concerns likely later this week into the weekend.

SHORT TERM
(This evening through Monday)
Issued at 230 PM PDT Sun Oct 13 2024

Fairly seasonal temperatures continue today as a shortwave ridge moves through our area. Inland highs are expected to reach into the upper 70s to low 80s while temperatures closer to the coast remain in the 60s. Satellite shows a mix of clear to scattered to overcast cloud cover across the Bay Area. For those heading to Fleet Week, cloud cover conditions will continue to improve over San Francisco with overcast midlevel clouds and scattered low level clouds continuing through the afternoon/evening before overcast conditions return late in the evening. Overnight lows will generally stay in the 50's with mid to upper 50's inland and low to mid 50's closer to the coast. Tomorrow's high temperatures will be fairly similar to today's with inland highs mainly in the mid to upper 70s with the hottest locations reaching into the low 80s. Coastal high temperatures, comparatively, will be a few degrees cooler thanks to the return of a more well defined marine layer overnight.

LONG TERM
(Monday night through next Saturday)
Issued at 230 PM PDT Sun Oct 13 2024

Heading into the long term we continue to monitor potential for rain midweek and elevated fire weather concerns late week through next weekend. Models show the synoptic pattern remaining fairly progressive with shortwave ridging expected to last through Tuesday.
A strong upper level low pressure system remains on track to move inland over the Pacific Northwest on Wednesday and bring some light rain to portions of our CWA There still remains some uncertainty as to how much precipitation it will bring as models have backed off significantly compared to the past few days. Chances for accumulating precipitation are highest in the North Bay (particularly northern Sonoma and Napa counties) but totals will generally be well below 0.1" everywhere in the North Bay. Any precipitation that the North Bay receives on Wednesday is not likely to meet "wetting rain" criteria and will have a negligible effect on increasing local fuel moisture.

The decrease in accumulating precipitation also brings us to our second concern: elevated fire weather concerns across the Bay Area and Central Coast beginning late Thursday through the weekend. Both the European and GFS models now show the upper level low continuing to strengthen and deepen as it moves eastward through California/Nevada before eventually becoming a cut-off low over the four corners region. Confidence is increasing that a classic fire weather pattern, an "inside slider", will develop and take place next weekend bringing widespread, gusty offshore winds across the Bay Area and Central Coast. At 850 mb late Thursday/early Friday, the GFS and Euro models are both showing gusts between at least 40 to 45 mph with the GFS model showing some potential for gusts close to 50 mph to develop. What does this translate to at the surface? At the surface gusts will generally be strongest across elevated terrain and mountain gaps/passes where peak gusts look to be between 35-40 mph currently. There is potential for stronger gusts to develop in the gaps and passes of the East Bay Hills where we may see 40+ mph gusts during this event. Forecasted sustained winds and wind gusts will continue to be refined as we continue to move closer to the Thursday/Friday timeframe. We will continue to monitor and provide updates on these fire weather concerns as they evolve over the course of this week. Residents of the Bay Area and the Central Coast should take precautions to avoid all activities that may result in wildfire spread/development next weekend. Remember: "One less spark, One less wildfire."

AVIATION
(00Z TAFS)
Issued at 419 PM PDT Sun Oct 13 2024

Currently VFR at all terminals with the exception of the Monterey Bay terminals of MRY and SNS. Moderate to high confidence in all terminals experiencing a reduction in flight category overnight with LIFR for the Monterey Bay terminals of MRY and SNS, IFR for the North Bay terminals of APC and STS, and MVFR for LVK, OAK, SFO, and SJC. With the exception of MRY, VFR is expected at all terminals by tomorrow afternoon.

Vicinity of SFO...Currently VFR with westerly flow. High confidence in a low-end MVFR ceiling developing overnight. Further deterioration to IFR is possible, but highest confidence is placed in a low-end MVFR ceiling. VFR forecast of 19Z is once again optimistic as some guidance/models are showing 21Z-22Z. Winds will prevail out of the west through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently MVFR with westerly flow at both terminals. Both terminals will further deteriorate to IFR early this evening with fog developing overnight. SNS will be VFR by the afternoon with MRY remaining sub-VFR through the TAF period.

MARINE
(Tonight through next Saturday)
Issued at 903 PM PDT Sun Oct 13 2024

Seas build through the forecast period, becoming rough Monday afternoon. Long period northwesterly swell of 13-17 seconds will result in elevated surf conditions through Wednesday. A strong upper-level low will bring widespread near-gale to gale force gusts beginning Thursday.

BEACHES
Issued at 850 PM PDT Sun Oct 13 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.

PZ...Small Craft Advisory from 3 PM Monday to 9 AM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0- 10 nm.