Technical NOAA Weather Discussion

FXUS66 KMTR 271208
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
408 AM PST Tue Jan 27 2026

...New AVIATION, MARINE, BEACHES...

.KEY MESSAGES...
Updated at 319 AM PST Tue Jan 27 2026

 - Mild with increasing cloud cover through the day

 - Increasing rain chances tonight through Wednesday morning for
   the North Bay into Bay Area, with light amounts between
   0.1"-0.2" expected where it does rain

 - Drier conditions and weak offshore flow return quickly by
   Wednesday afternoon

 - Beach Hazards Statement for increased risk of sneaker waves 
   and riptides Wednesday night through Friday Morning

&&

.SHORT TERM...
Issued at 319 AM PST Tue Jan 27 2026
(Today and tonight)

The 00z KOAK sounding recorded 0.43" PWAT last night with HiRes 
short-term soundings indicating similar or lower values until after 
sunrise this morning in the North Bay, with the boundary layer not 
beginning to saturate until later this morning into the afternoon 
that far north. Prefrontal drizzle or light rain is possible along 
the North Bay coastal ranges later this morning into the afternoon 
with the added lift. Otherwise, the bulk of the rainfall is expected 
to move inland after sunset tonight, and shift east by sunrise 
Wednesday morning. Slight chance PoPs extend as far south as the 
Santa Cruz mountains later today and tonight, however rain totals 
south of the North Bay are expected to be less than 0.1" where it 
does rain. Inland areas of the North Bay like Santa Rosa are likely 
to see around 0.20" (mean hi-res ensemble %) with higher end 
reasonable amounts near 0.30" (hi-res 75th%), thus little impacts
beyond wetting rainfall are expected. Lesser amounts are expected
farther east as the progressive shortwave trough moves out of our
area to the east.

&&

.LONG TERM...
Issued at 319 AM PST Tue Jan 27 2026
(Wednesday through Monday)

The progressive upper level trough moving across the North Bay will 
shift east Wednesday morning with a ridging pattern developing 
quickly in its wake. Weak offshore flow will return as a result with 
another dry airmass filling in for the remainder of the work week 
into the beginning of weekend. Long period westerly swell and 
increasing wave heights will result in an increased risk of sneaker 
waves and riptides along with breaking waves up to 19ft Wednesday 
night through Friday morning, with a Beach Hazards statement issued 
for that time period, see the Beach Hazards discussion for more 
details. Slight chance PoPs return as soon as late Saturday night 
into Sunday for the North Bay once again, however a lack in 
consensus of the location, depth and timing of the developing trough 
leaves far more questions than answers at this point.

&&

.AVIATION...
(12Z TAFS)
Issued at 359 AM PST Tue Jan 27 2026

Pockets of fog are affecting the North Bay as will as LVK and HAF, 
while the rest of the TAF sites remain VFR. High clouds continue to 
build into the region through much of the the day as the next front 
nears with mid-level clouds arriving into the afternoon. Expect 
light rain and MVFR clouds along the front as it passes through the 
area tonight. The front will also offer moderate southerly winds 
with weaker, shifting winds behind it. Cloud cover will be slow to 
erode in the post-frontal environment into Wednesday morning, with 
trapped moisture in the North Bay causing IFR CIGs. 

Vicinity of SFO...VFR lasts into the night. Expect mostly light and 
variable winds through the late morning before turning southwest for 
the afternoon and the evening. MVFR CIGs and light rain arrives with 
the front into the night, while winds turn southerly. CIGs linger 
into the late night as rain chances exit and winds turn westerly. 
VFR returns in the mid to late morning on Wednesday as winds turn 
northerly and CIGs lift and scatter.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Light and 
affect MRY through the forecast. Winds stay east to southeast 
through the morning and into the mid afternoon, with more moderate 
winds possible at SNS. Winds turn southwest at MRY for the 
afternoon, while SNS goes northwest. Light rain moves through the 
area into the night, but does not look to be impactful. These rains 
will be accompanied by mid-level clouds.

&&

.MARINE...
(Today through Sunday)
Issued at 359 AM PST Tue Jan 27 2026

Light to moderate southerly flow will prevail over most of the
waters as a weak cold front approaches from the west through
Tuesday. Winds will be moderate to breezy north of Point Reyes
with locally hazardous conditions for small craft. Winds diminish
on Wednesday and switch to northerly that night. Moderate seas
will prevail through Tuesday, but  build rough to very rough
Wednesday night. The passing cold front will bring light rain to
the coastal waters early Tuesday morning through Wednesday
morning.

&&

.BEACHES...
Issued at 359 AM PST Tue Jan 27 2026

Long period swells with low wave  heights begin to arrive on 
Wednesday, but wave heights begin to increase that night while 
periods stay long leading to hazardous conditions. A Beach 
Hazards Statement has been issued from 09 PM Wednesday through 09 
AM Friday. Significant wave heights look to range from 14 to 19 
feet. The main threat will be from sneaker waves and rip currents.
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.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from Wednesday evening through Friday 
     morning for CAZ006-505-509-529-530.

PZ...Small Craft Advisory until 9 PM PST this evening for Pt Arena to 
     Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 9 AM Thursday to 3 AM PST Friday for 
     Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 AM Thursday to 3 AM PST Friday for 
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Murdock
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Tue Jan 27 06:30:03 PST 2026
From the National Weather Service