643
FXUS66 KMTR 030510
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
910 PM PST Mon Nov 2 2026

...New UPDATE...

.KEY MESSAGES...
Updated at 228 PM PST Mon Nov 2 2026

 - Hazardous beach conditions through Tuesday evening and again
   Thursday through Saturday

 - Light to moderate rain across North Bay tonight through
   Tuesday; light rain across rest of Bay Area

 - Seasonal to slightly below normal temps through midweek;
   warming trend and above normal temps late week into weekend

&&

.UPDATE...
Issued at 858 PM PST Mon Nov 2 2026

KMUX radar was flipped into precip mode earlier in the evening
thanks to a few scout showers ahead of the next low pressure
system. Even surface analysis shows an occluded sfc low pressure
due west of the CA/OR border and the triple point due west of Pt
Arena. The scout showers are likely tied to some moderate
isentropic lift or upglide - warmer air riding or gliding up and
over cooler air ahead of the sfc low. Expect these showers to
increase in coverage over the coastal waters this evening as the
low moves eastward. Latest timing brings showers to the N Bay
coast by sunrise.

Highlights for tomorrow still remains the same and ontrack: wet
commute, chc thunder N coastal waters and Sonoma county, precip
impacting rest of CWA except interior Central Coast.

MM

&&

.SHORT TERM...
Issued at 228 PM PST Mon Nov 2 2026
(This evening through Tuesday night)

Widespread cloud cover is building in ahead of tonight`s rain
showers. Showers approach the coast late tonight as a surface low
pressure system moves southwards offshore of Northern California.
This is a cold-core system and will bring in a much colder airmass,
resulting in well below normal temperatures at the surface. Highs
will be in the upper 50s to mid 60s with the coolest locations
across the higher elevations. So when will you start feeling
impacts? The latest high resolution guidance shows the main rain
band approaching the coast around ~5-6AM with showers reaching the
coastal North Bay by 7-8AM and filtering into the rest of the Bay
Area through the remainder of the morning. There is a low (< 10%)
chance of thunderstorms with this first rain band moving onshore.
Rain totals are forecast to be highest across the coastal North Bay
Mountains from Sonoma to Marin with between 0.5-0.75". The rest of
the North Bay and the Santa Cruz Mountains will see 0.25-0.5" while
the remainder of the Bay Area sees less than a tenth of an inch. The
heaviest rain will impact the morning commute so remember to slow
down, allow extra time to reach your destination, and be prepared
for slick roads.

The more interesting possibility, thunderstorm wise, is a secondary
band of discrete showers that develops offshore after the initial
rainband moves inland. These showers are characterized by a more
discrete (individual) look and develop in a more unstable marine
environment. Thunderstorm chances increase to 15-20% for the coastal
North Bay and northern outer waters late Tuesday morning through
late Tuesday afternoon as the second round develops and moves
inland. The second round is interesting for a few reasons. The first
is that the more discrete nature of the storms may allow for further
strengthening and will increase the likelihood of thunderstorm
development. Cooler air aloft will filter in behind the surface low
and promote the formation ice crystals, should a storm develop,
increasing the potential for lightning. Forecast sounding data
suggests good low level shear in the lowest 0 to 1 kilometers with
decent speed and directional shear. The stronger the shear the more
likely the storm is to rotate which increases the potential for
waterspouts to develop. Current thinking is that waterspouts will be
possible offshore with this second round of storms. The caveat is
that we will likely need some sort of instability generation (i.e.
clouds clearing and warming the surface over the ocean) to instigate
offshore thunderstorm development. If we do not see that clearing
then the potential for thunderstorms drops off significantly. Either
way, it will definitely be worth keeping an eye on the forecast and
making sure you have weather alerts turned on on your phone in the

&&

.LONG TERM...
Issued at 228 PM PST Mon Nov 2 2026
(Wednesday through next Sunday)

Conditions warm up and dry out Wednesday through the weekend as the
surface low dissipates/the upper level trough progresses eastward
and ridging builds. This will see a return of more seasonal to
slightly above normal temperatures in the upper 60s to 70s with
patchy 80s across far interior locations. Overnight lows remain more
mild in the 40s to 50s. Diurnally breezy winds return along the
coast and across mountain gaps/passes but no major concerns with
regards to this. Rain chances increase sometime around the 10/11
with the CPC and ensembles highlighting a likely prolonged period of
rain across the West Coast mid-month.

&&

.AVIATION...
(00Z TAFS)
Issued at 423 PM PST Mon Nov 2 2026

VFR continues tonight then cloud ceilings will steadily lower to
MVFR Tuesday with showers developing mainly Tuesday up through
frontal passage Tuesday.

Vicinity of SFO...VFR-MVFR with steadily lowering cloud ceilings
and showers developing Tuesday. West wind 5 to 7 knots early this
evening otherwise wind shifting to southeasterly 5 to 10 knots
Tuesday morning then to southwesterly 12 to 22 knots 19z Tuesday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR-MVFR with steadily lowering cloud
ceilings and showers Tuesday. Onshore winds 5 to 10 knots becoming
light and variable to light southeasterly tonight and Tuesday. Wind
shifting to westerly near 10 knots late Tuesday afternoon and early
evening.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 239 PM PST Mon Nov 2 2026

Seas will continue to build across the outer waters tonight
through Wednesday morning, becoming rough and bringing hazardous
conditions for small craft. Gentle to moderate northwesterly
breezes will increase and back tonight to become moderate to fresh
southwesterly breezes ahead of an approaching cold front. Rain
moves in Tuesday with this system, bringing with it a 15-20%
chance of thunderstorms north of Pigeon Point. Moderate to fresh
northerly breezes and moderate to rough seas will prevail
Wednesday through Friday.

&&

.BEACHES...
Issued at 1229 AM PST Mon Nov 2 2026

Hazardous beach conditions will be present at Pacific Coast beaches
Monday and Tuesday as long period (15-19 second) northwesterly swell
will bring an increased risk for sneaker waves and strong rip
currents. Waves can sweep across the shoreline without warning,
pulling people into the sea from beaches, jetties, and rocks. Stay
off of jetties, piers, rocks, and other waterside infrastructure.
Remain out of the water to avoid hazardous surf and never turn your
back on the ocean!

Sarment

&&

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

PZ...Small Craft Advisory from 3 AM Tuesday to 9 AM PST Wednesday for
     Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Tuesday to 9 AM PST Wednesday for
     Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Canepa
MARINE...KR

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