606
FXUS66 KMTR 020506 AAC
AFDMTR

Area Forecast Discussion...UPDATED
National Weather Service San Francisco CA
1006 PM PDT Sat Nov 1 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 309 AM PDT Sat Nov 1 2025

 - Quiet and warm through the weekend with hazardous beach
   conditions at Pacific Coast beaches

 - Next storm system on tap for late Tuesday/Wednesday, widespread
   rainfall, highest totals North Bay

 - Potential for a brief hazardous wind threat Wednesday morning

&&

.UPDATE...
Issued at 922 PM PDT Sat Nov 1 2025

Satellite imagery shows patches of coastal stratus along the San
Mateo Peninsula, the Monterey Peninsula, and the Big Sur coast.
Profiler data from Bodega Bay amd Point Sur suggests that the marine
layer remains shallow, around 500 feet deep at most. There is still
some model guidance that suggests that a slight deepening to 1000
feet is possible overnight, but this is a low to moderate confidence
forecast.

One thing to note for the medium-term forecast: on Sunday, a
baroclinic low develops on the backside of a cold front coming
through the North Coast. This low will be sited somewhere off the
North Coast-southern Oregon region, allowing offshore downsloping
flow to come off the mountains of southwestern Oregon and then
wrapping around the low into the Bay Area. This dry slot is forecast
to arrive in the region Sunday night through Monday morning, with
the potential impacts including nocturnal drying across the region
and interference with the development of stratus clouds that night.
Will keep an eye on the development of the forecast through the
night and into the day on Sunday.

DialH

&&

.SHORT TERM...
Issued at 140 PM PDT Sat Nov 1 2025 (This evening through Sunday)

Outside of a few patches of clouds along the immediate coastline
we have wall to wall sunshine blanketing the Bay Area and Central
Coast. Not a bad way to begin November. Highs today will top out
in the 60s to lower 80s, or as much as 10 degrees above normal.
If you prefer cool and wet weather, just wait. You`ll have your
turn, see Long Term.

For tonight - shallow marine layer coupled with lighter flow will
lead to some patchy dense fog again. Probabilistic guidance gives
the North Bay Valleys and Monterey Bay coast about 30% chc of vis
less than one mile. Location wise that is very similar to this
morning. Would like higher probs before issuing Dense Fog this
far out. Will need to monitor closely tonight.

Sunday - almost a repeat of Saturday. Overall sensible weather
will be similar. Temperatures in the 60s to 80s. A few interior
spots will make a run into the mid 80s.

&&

.LONG TERM...
Issued at 240 PM PDT Sat Nov 1 2025
(Sunday night through next Friday)

To kick off another work week we can expect a quiet start weather
wise with seasonably mild temperatures. That will quickly change
Monday night into Tuesday as we see a marked change in the
longwave pattern. Let`s take a broader look at the water vapor
imagery over the Northern Hemisphere this afternoon. There is a
small ripple currently over Siberia. This ripple will get picked
up by upper level flow. A anomalously strong 150kt jet will take
the ripple, push through the Aleutians and undergo enhanced
cyclogenesis. By Tuesday, latest guidance shows a notably strong
970-980mb low spinning off the PacNW coast. The fetch zone to the
south of the deepening low will tap into a moisture plume tracking
NE from the sub-tropics. IVT (integrated vapor transport) and IWV
(integrated water vapor) values rapidly climb over OR/CA by
Tuesday before moving southward into the Bay Area by early
Wednesday. Pretty impressive values being seen on Atmospheric
River Guidance for IVT and IWV 12z Wednesday. Later in the season
this would be more of a problem with wetter soils and fuller
streams/creeks/rivers. Thankfully, guidance pushes the moisture
plume through the region rather quickly. That`s not to say we
won`t have a period of moderate to heavy precip on Wednesday, but
likelihood of stalling is less. Minor to moderate hydro concerns
will be possible during this time period on Wednesday. As with may
early season systems this system will fade in strength and
intensity as it progresses southward Wednesday afternoon into
Thursday. As such, high moisture content and resulting precip are
still focused Golden Gate northward. Steadier rainfall will
transition to move showers and taper off N to S during the day
Thursday. Rainfall amounts have trended upward slightly with WPC
placing portions of Sonoma in an Excessive Rainfall Outlook on
Wednesday. Rainfall totals Tuesday through Thursday: North Bay
1-2", Bay Area 0.5-1" (some rain shadowing possible for San Jose),
Central Coast a few 0.01-0.5".

A secondary moisture push on Thursday night into Friday will
bring a renewed chance for precip across the North Bay.

Two other impacts with this system that we`ll be fine tuning will
be thunderstorms and wind.

Latest guidance has now shown more instability and higher chances
for thunder with the front and moisture plume on Wednesday. A
15-25% chc of thunderstorms have been added to the forecast. Main
threats will be gusty winds and heavy rain.

As for wind, EC Extreme Forecast Index continues to advertise a
solid wind threat for the Bay Area (north of Monterey Bay). Not
only are there abnormally high winds being forecast there is also
a higher percentage of the ensemble members saying so, esp Mendo
county. In other words, higher confidence for stronger winds. Will
likely need some Wind Advisory or High Wind Warning for portions
of the Bay Area, coast/mts. This will be the first real wind test
of the season. For those keeping score at home, some of the CAMs
show absurd winds of 80-90 mph off the NorCal near Arcata.

&&

.AVIATION...
(06Z TAFS)
Issued at 950 PM PDT Sat Nov 1 2025

Confidence in the forecast remains low to medium, but the latest
satellite imagery does show a gradual development of marine
stratus. As a result, the latest iteration of the TAFs holds
remains largely unchanged. Conditions will deteriorate between
06-08Z Sun at KHAF and North Bay sites with ceilings and
visibilities approaching airport minimums. The window for IFR
farther south remains the same around 10Z at KOAK. Intermittent
MVFR at KSJC is still anticipated, through the probability is low
and I do anticipate that it`ll be brief/occasional. The
compressed marine layer should equate to a rapid erosion of
stratus, mist, and fog by 17-18Z, except at KHAF where poor
conditions remain through mid- afternoon.


Vicinity of SFO...MVFR and intermittent IFR are forecast with
medium confidence. At present time, cigs are anticipated to
invade just prior to 11Z with occasional IFR. Guidance continues
to remain insistent in IFR and this is the trickiest part of the
forecast, as climatologically this is out of the norm. Future
updates will likely need to alter the timing. VFR is anticipated
to return late morning with diurnal NW`ly breezes funneling
through the San Bruno Gap. There are some indications that
MVFR/IFR may return after 00Z Monday, but from a big picture,
there may be some dry air that chews up some of the moist marine
layer air on the backside of a developing surface low. Given some
of the variability in the extended portion of the TAF, I`ll
advertise VFR, but trends in model output will be monitored.

SFO Bridge Approach...VAPS currently, but loss of VAPS likely by
the Sunday AM push. Cigs should scatter near or after 18Z Sunday.

Monterey Bay Terminals...Stratus has been a little slow to
develop, but it is in progress across southern portions of the
Monterey Peninsula. LIFR to VLIFR visibility and ceilings appear
to be most likely at these terminals for a few hours on Sunday
morning with VFR not returning near or after 18Z. Confidence in
exact timing of stratus development is low, but there`s high
confidence that by the 6Z to 9Z timeframe that LIFR/VLIFR will be
in place at the terminals.

&&

.MARINE...
(Tonight through next Friday)
Issued at 922 PM PDT Sat Nov 1 2025

Fresh to near gale-force breezes will continue through Sunday
before abating early Monday, except for regions near Monterey Bay
and south of Point Sur. Gentle to moderate breezes should be
anticipated on Tuesday, before a vigorous storm system approaches.
Very hazardous boating conditions are anticipated on Wednesday as
gale force, possibly severe, wind gusts are probable. The greatest
potential will be for areas near and north of Point Reyes. Steep
seas and very rough conditions should be anticipated around mid-
week. In addition, showers and thunderstorms will also pose
lightning, higher end wind, and poor visibility risk to all
mariners.

&&

.BEACHES...
Issued at 922 PM PDT Sat Nov 1 2025

A long period northwesterly swell will bring an increased risk for
sneaker waves, rip currents, and breaking waves of up to 20 feet
to Pacific Coast beaches through Monday. The sneaker wave risk
remains low to moderate through Monday and will likely elevate
through the middle to end of next week. High surf conditions are
possible, especially at the west and northwest facing beaches.
Remember, sneaker waves can unexpectedly run significantly farther
up the beach than normal, including over rocks and jetties. Rip
currents are typically more frequent and stronger in the vicinity
of jetties, inlets, and piers. Swimmers should always swim near a
lifeguard. Stay off the rocks, remain out of the water to avoid
hazardous swimming conditions, and never turn your back on the
ocean!

Bain/Sarment

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through late Monday night for CAZ006-505-
     509-529-530.

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

     Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt
     Pinos 0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Pigeon Pt
     to Pt Pinos 0-10 nm.

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

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Bain
MARINE...Bain

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