FXUS66 KMTR 311139
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
339 AM PST Sat Jan 31 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1245 AM PST Sat Jan 31 2026
- Pleasant, warm, and dry conditions persist through the next
week
- Minor coastal flooding directly along the bayshore along the
San Francisco, San Pablo, and Monterey Bays through Sunday
- Hazardous beach conditions due to an increased risk of sneaker
waves and rip currents for Pacific Coast beaches through Monday
&&
.SHORT TERM...
Issued at 1245 AM PST Sat Jan 31 2026
(Today and tonight)
Thin high level clouds blanket the satellite imagery, making it hard
to evaluate the evolution of fog and low stratus across the region.
Surface observations suggest that patchy fog and mist have
developed, mainly in the North and East Bay valleys. The thin high
clouds are lowering confidence in the amount of radiational cooling
and thus any further expansion of the stratus layer, but expect the
stratus impacts to persist through the morning.
The weather pattern continues to center around an upper level ridge
that is slowly progressing into the Great Basin, giving us another
day of seasonably warm temperatures. In particular, San Jose
continues to flirt with a daily record high today; the current
forecast high of 69 is just two degrees cooler than the record of 71
set in 1962 and tied in 2015. Elsewhere across the region, high
temperatures range from the middle 60s in the interior valleys of
the North and East Bay, the lower 70s in the Monterey Bay region,
the middle to upper 70s in the South Bay and the interior Central
Coast valleys, and the lower 60s across the North Bay Pacific coast,
into the Bayside areas of the North Bay and the far interior
portions of Contra Costa County. Winds will be light with a
generally offshore component across the inland regions, while a
light onshore breeze develops along the coast in the afternoon.
Minor coastal flooding is possible for low-lying areas directly
along the bayshore of the San Francisco, San Pablo, and Monterey
Bays near high tide today and Sunday, the result of a combination of
elevated astronomical tides and storm surge from the system off the
coast of British Columbia. Note that we are not anticipating major
coastal flooding impacts like those seen at the beginning of the
month, and will be limited to those locations that typically see
impacts from the King Tides. At the San Francisco tidal gauge, the
maximum inundation is expected to be around 1.3 feet above normally
dry ground, or 7.20 ft MLLW, at around 9:30 AM today; this figure
includes impacts from both astronomical tides and storm surge. High
tide timing varies up to 90 minutes earlier or later along the
Pacific Coast and through the San Francisco Bay, respectively.
&&
.LONG TERM...
Issued at 1245 AM PST Sat Jan 31 2026
(Sunday through Friday)
A shortwave trough will brush past the region on Sunday as the ridge
continues to move off to the east, leading to a more zonal upper
level pattern across the region. With any rain chances now far to
the north of our area of responsibility, the most prominent impact
to the sensible weather will be increased cloudiness, brisker winds,
and a slight cooling trend across the South Bay into the Central
Coast. High temperatures for Sunday and Monday will dip into the
middle 60s to near 70 across the Santa Clara Valley and the Monterey
Bay region, while the Salinas Valley dips into the lower to middle
70s.
Upper level ridging redevelops over the West Coast by Tuesday and
persists into the end of the 7-day outlook, and temperatures should
rebound to the middle 60s to middle 70s in the interior valleys. The
very tail end of the outlook does show the ridge beginning to break
down with an associated slight cooling beginning next Friday, but
the weather should remain dry. The CPC 6-10 day outlook, covering
February 5 to 9, continues to show a high likelihood (80-90%
probability) of temperatures above seasonal averages, and a lean (40-
50% probability) of rainfall totals below seasonal averages for the
stated period. For context, downtown San Francisco's long term
averages for this period are for a high of 60 degrees and a rainfall
total around three quarters of an inch. Beyond that, ensemble model
means are starting to depict some chances of rain around the 10th,
but as the previous forecaster noted, the models have consistently
shown rain at the very end of their runs before backing off as the
day gets closer, so any increase in forecaster confidence will
depend on whether the trend for rain around the 10th persists as it
gets closer.
&&
.AVIATION...
(12Z TAFS)
Issued at 339 AM PST Sat Jan 31 2026
Currently a mixed bag of LIFR-VFR at the terminals. High confidence
in VFR by this afternoon. A decaying cold front will encroach the
region tonight, leading to cooler and moister conditions and the
return of onshore flow which will bring renewed chances for sub-VFR
conditions to all terminals. The TAFs are pessimistic with a
reasonable earliest arrival of reduced visibilities/cloud decks.
Vicinity of SFO...Currently MVFR with light easterly winds and mist
being observed. Aside from the mist this morning, VFR is expected to
prevail at least through this afternoon. Reasonable worst case
scenario of sub-VFR conditions returning as early as 06Z tonight.
Light northerly/northeasterly winds will prevail.
SFO Bridge Approach...MVFR visibilities are being observed along the
San Mateo Bridge Approach. There's a low probability (less than 35%
chance) that radiative stratus below FL040 will develop through this
morning. High confidence in VFR by this afternoon.
Monterey Bay Terminals...Currently VFR and calm at MRY and VFR with
drainage flow at SNS. Diurnal winds will prevail. Low probability
(25%) for sub-VFR conditions (likely IFR) to return tonight.
&&
.MARINE...
(Today through Thursday)
Issued at 339 AM PST Sat Jan 31 2026
Moderate seas and a gentle northerly/offshore breeze will prevail
today. Hazardous marine conditions return tomorrow morning and
persist through Monday as seas build to become rough for the
inner waters and outer waters and northerly breezes increase to
become fresh to strong. Conditions improve Tuesday with moderate
seas and a gentle northerly breeze prevailing through Wednesday.
&&
.BEACHES...
Issued at 333 AM PST Fri Jan 30 2026
Hazardous beach conditions will continue through Monday at all
Pacific Coast beaches. Long period westerly swell will bring an
increased risk for sneaker waves and strong rip currents with
breaking waves of 14 to 19 feet. Remember: stay off of jetties,
piers, rocks, and other waterside infrastructure, remain out of
the water, and never turn your back on the ocean!
&&
.CLIMATE...
Issued at 647 PM PST Fri Jan 30 2026
The following are the record high temperatures at the long term
sites for January 31st.
Location Jan 31st Record High
Santa Rosa 73 in 1953
San Rafael 78 in 2015
Kentfield 75 in 2015
Napa 77 in 2015
Richmond 75 in 2015
Livermore 79 in 2022
San Francisco 74 in 2015
SFO Airport 74 in 2015
Redwood City 75 in 2015
Half Moon Bay 72 in 2015, 1976, 1962
Oakland Museum 78 in 2015
San Jose 71 in 2015, 1962
Salinas Airport 79 in 1976
King City 85 in 1976
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Monday morning for CAZ006-505-
509-529-530.
Coastal Flood Advisory until noon PST Sunday for CAZ006-506-508-
529-530.
PZ...Small Craft Advisory from 9 AM to 3 PM PST Sunday for Pt Arena
to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Sarment
MARINE...Sarment
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Prepared by Boulder-Creek.com Weather at: Sat Jan 31 04:30:02 PST 2026
From the National Weather Service
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