FXUS66 KMTR 172347
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
447 PM PDT Sat Oct 17 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 139 PM PDT Sat Oct 17 2026

 - Very warm temperatures continue today

 - Hazardous beach conditions through at least this weekend

 - Much cooler weather arrives Sunday with rain chances midweek

&&

.SHORT TERM...
Issued at 139 PM PDT Sat Oct 17 2026
(This evening through Sunday night)

This afternoon is shaping up to be another very warm day with 
temperatures reaching into the upper 80s to low 90s across the 
interior, around the Santa Cruz region, and Monterey Bay region. 
Temperatures reached the low 90s around Monterey region as onshore
flow was delayed. However, the onshore flow has returned cooling 
temperatures into the upper 70s to mid 80s. The immediate 
coastline is forecast to remain in the low-to-upper 70s. That 
said, the high pressure over northern California is weakening and 
will continue to do so through the remainder of the weekend.

The cooling trend will be more robust tonight and into Sunday as 
a dry frontal boundary moves across the Bay Area and north Central
Coast. This will also allow for a slightly stronger onshore flow 
and deepening marine layer (albeit temporarily) and more 
seasonable temperatures. Thus, temperatures will be some 10-15 
degrees or more cooler than today. 

&&

.LONG TERM...
Issued at 139 PM PDT Sat Oct 17 2026
(Monday through next Friday)

A more robust cool down will occur Monday as the upper-level 
trough deepens off of the West Coast, bringing temperatures to 
below seasonal averages. The trough becomes a cut-off low by 
Tuesday with its center approximately 350 miles west of San 
Francisco. This will bring a cold front through the region Monday 
night into Tuesday morning as the center of the low pressure 
system pushes inland across the south Central Coast and/or 
southern California Wednesday evening into Thursday. This will 
result in unsettled weather conditions across the region Tuesday 
through Thursday. 

As far as precipitation and thunderstorm chances go, there is a 
20- 40% chance of rain showers across the greater Bay Area and 
30-60% chance across the Central Coast. The greatest potential for
convection is now on Wednesday when the core of the low begins to
move onshore. The greatest potential (generally 15% or less) will
be over the offshore waters and Central Coast where the greatest 
instability will be located. 

A further offshore and southern track of the low pressure system 
would result in less rainfall and lower probability for 
convection. However, if it were to move directly into the Central 
Coast (or even the Bay Area) we would have stronger winds, heavier
rain, and increased potential for thunderstorms. Thus, be sure to
check back on the forecast as the event draws nearer. 

&&

.AVIATION...
(00Z TAFS)
Issued at 442 PM PDT Sat Oct 17 2026

Lingering weak offshore flow has kept dry air in place with VFR 
conditions. Expect VFR through most of tonight. Guidance still 
gives about a 30% chc for MVFR at KSTS, but given the conf will 
keep the SCT to show some poss clouds. IFR to LIFR more likely at 
KHAF,KMRY,KSNS tomorrow with shallow moisture layer. Overall conf
remains high.

Vicinity of SFO...VFR. Gusty onshore this evening then weakening
overnight. Onshore push again tomorrow afternoon with gusts over
20kts.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through early tonight. Need stratus
to develop overnight and if it does it will be shallow leading to
IFR to LIFR conditions Sunday AM.  VFR Sunday afternoon. 

&&

.MARINE...
(Today through Thursday)
Issued at 1002 AM PDT Sat Oct 17 2026

Moderate to fresh northwesterly breezes will prevail through
Monday with strong breezes across the northern outer waters.
Widespread hazardous conditions will spread across the coastal
waters as a result Sunday afternoon, likely continuing into
Monday. Moderate seas will prevail across the inner waters with
rough seas building across the outer waters Saturday through
Monday, rebuilding again Tuesday. Light rain is expected Monday
night through Wednesday.

&&

.BEACHES...
Issued at 1002 AM PDT Sat Oct 17 2026

Hazardous beach conditions will be present at Pacific Coast beaches 
through Sunday and likely into next week. Long period 
southerly/southwesterly swell will bring an increased risk for 
sneaker waves and strong rip currents with breaking waves of 7 to 12 
feet. Remain off jetties, piers, rocks, and other waterside 
infrastructure as waves can sweep across the shoreline without 
warning, pulling people into the sea. Never turn your back on the
ocean!



&&

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

PZ...Small Craft Advisory from 3 AM to 9 PM PDT Sunday for Pt Arena 
     to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Pigeon Pt 
     to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos 
     to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 PM PDT Sunday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...MM
MARINE...Sarment

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Prepared by Boulder-Creek.com Weather at: Sat Oct 17 18:30:03 PDT 2026