FXUS66 KMTR 300418
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
918 PM PDT Sat Aug 29 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1240 PM PDT Sat Aug 29 2026

 - Cooling trend continues through at least midweek

&&

.SHORT TERM...
Issued at 1240 PM PDT Sat Aug 29 2026
(This evening through Sunday night)

Mostly sunny sky conditions have return to the region this 
afternoon. This will lead to warmer conditions today over the North 
Bay with the lack of mid/upper level high clouds. However, 
temperatures across the region with be a few to several degrees 
below normal as an mid/upper level low pressure system moves into 
the Pacific Northwest and British Columbia. 

The marine layer is forecast to deepen through the weekend. However, 
with clearing skies off of the North Bay coast this afternoon, less 
confidence for a return of stratus/fog overnight and into Sunday 
morning. Still anticipate at least a patchwork of stratus/fog to 
develop late this evening and moreso into Sunday morning along the 
coast and into the adjacent valleys. For Sunday, expecting more of 
the same as troughing persist along the West Coast. 

&&

.LONG TERM...
Issued at 1240 PM PDT Sat Aug 29 2026
(Monday through next Friday)

A reinforcing trough develops and begins to deepen off of the 
Pacific Northwest coast through the middle of the upcoming week. As 
a result, afternoon temperatures will be some 5 to 15 degrees below 
normal for this time of year. This will system will likely bring 
rainfall to the Pacific Northwest. By late week, the NBM is 
suggesting a better chance of rain/rain showers as the trough off of 
the West Coast continues to deepen and potential drags a weak 
frontal boundary across the region. There is still low to 
moderate confidence of this occuring. 

&&

.AVIATION...
(06Z TAFS)
Issued at 918 PM PDT Sat Aug 29 2026

VFR prevails across the forecast area except for a newly 
developing patch of stratus /MVFR-IFR/ vicinity KHAF Airport and 
wildfire smoke reducing slant range and surface visibilities in 
southern Monterey County. A well established deep layered mid-
latitude wind flow returned last night and today which thoroughly 
dried out the atmosphere at and above the lower level subsidence 
inversion (temperature inversion based at 1600 feet per latest 00z
Oakland upper air sounding). Earlier today this drying combined 
with surface heating and fully mixed out even lingering coastal 
stratus and fog. Independent of the 500 mb pattern, thermal ridging
remains between 925 mb and 700 mb tonight and Sunday. Model forecasts
show stratus and fog returning tonight and Sunday morning, though
it'll take time for redevelopment. A dry atmosphere above the 
lower level temperature inversion will result in radiative cooling
tonight to daybreak Sunday. This and any near surface cool air 
advection and gentle upslope cooling will help coastal stratus 
and fog redevelopment. Most inland locations likely stay VFR 
tonight and Sunday.

Vicinity of SFO...VFR except tempo stratus /IFR/ 11z-15z Sunday.
Stratus /IFR/ then returns early Monday morning. West wind 16 to 
25 knots until 07z this evening, then west wind 10 knots tonight 
and Sunday morning. West wind 15 to 22 knots Sunday afternoon to 
mid evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Radiative cooling combining with 
gentle upslope cooling will result in stratus and fog/mist /IFR-
LIFR/ redevelopment tonight to daybreak Sunday. Tempo stratus and
fog/mist /LIFR/ forecast 09z-14z, prevailing LIFR until late 
Sunday morning. Stratus, fog/mist mix out to VFR 17z Sunday. Stratus
/IFR/ redevelops Sunday night. Winds mainly west to northwest 5 to
15 knots.

&&

.MARINE...
(Tonight through next Friday)
Issued at 909 PM PDT Sat Aug 29 2026

Fresh northwest breezes with strong to near gale force gusts
steadily diminish to gentle by Monday. A long period southerly
swell around 17 to 18 seconds persists into Sunday. Wind driven
rough seas gradually subside back to moderate by the beginning of
the work week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Sunday for Mry Bay-Pigeon Pt 
     to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt 
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

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

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Canepa
MARINE...Canepa

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Prepared by Boulder-Creek.com Weather at: Sat Aug 29 22:30:03 PDT 2026