881
FXUS66 KMTR 012151
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
251 PM PDT Sat Nov 1 2025

...New SHORT TERM, LONG TERM...

.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

&&

.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...
(18Z TAFS)
Issued at 1051 AM PDT Sat Nov 1 2025

Stratus and fog /IFR-LIFR/ are slowly mixing out, otherwise it`s
VFR. Expect light winds to locally onshore 10 to 15 knots during
the late morning and afternoon, for tonight and Sunday morning
light winds. Stratus and fog /IFR-LIFR/ redevelops tonight and
Sunday morning, mixing out by late morning and early afternoon.

Vicinity of SFO...VFR except tempo IFR ceiling due to stratus
Sunday morning 02z-16z. West to northwest wind 7 to 14 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus and fog /IFR-LIFR/ mostly mixing
out, it`ll be VFR during the afternoon except stratus and fog MVFR-
IFR may linger along the coastline. Stratus and fog /MVFR-IFR/
moving inland tonight and Sunday morning. Onshore winds 5 to 10
knots becoming light and variable late tonight and Sunday morning.

&&

.MARINE...
(Today through Thursday)
Issued at 1043 AM PDT Sat Nov 1 2025

Moderate to fresh northerly breezes will prevail through the
weekend with strong gusts for the inner waters and outer waters.
Moderate to rough seas for the inner waters and very rough seas
for the outer waters will prevail through the weekend. Conditions
improve Monday with winds diminishing to become moderate and seas
abating to become rough in the outer waters. Conditions
deteriorate Tuesday night into Wednesday morning with very rough
seas for the outer waters, rough seas for the inner waters, strong
to near-gale southerly breezes with widespread gale force gusts,
and rainfall.

&&

.BEACHES...
Issued at 416 AM PDT Sat Nov 1 2025

A long period northwesterly swell will bring an increased risk for
sneaker waves, rip currents, and breaking waves of 12-17 feet to
Pacific Coast beaches through Monday. 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. Remain out of
the water to avoid hazardous swimming conditions and never turn
your back on the ocean!

&&

.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...Canepa
MARINE...Canepa

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