FXUS66 KMTR 101124
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
324 AM PST Tue Feb 10 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 211 AM PST Tue Feb 10 2026
- Widespread rain arrives to the region later today with showers
persisting through Thursday morning.
- Strong south winds this afternoon into Wednesday morning with
gusts of 40-50 mph along the Big Sur coast and higher terrain
in Monterey and San Benito Counties.
- General risk of thunderstorms this afternoon through Wednesday
with chances for lightning, localized gusty winds, small hail,
and locally heavy rain.
- Break in rain chances late Thursday into Friday before a wetter
pattern returns Saturday into the early part of next week.
&&
.SHORT TERM...
Issued at 211 AM PST Tue Feb 10 2026
(Today through Thursday)
Satellite imagery shows mid- to high-level clouds across the region.
Low temperatures this morning will drop into the upper 30s to middle
40s in the inland valleys, with lows in the middle 40s to upper 50s
along the coast and the bays. High temperatures today range from the
upper 50s to lower 60s across the coast and the valleys, and the
upper 40s to middle 50s in the higher elevations. Light winds will
continue for the rest of the overnight period, with the winds
increasing through the morning in advance of an incoming low
pressure system.
As of 1 AM today, a low pressure system was centered around 34N
130W, or around 500 miles to the west-southwest of San Francisco.
This low pressure system is expected to approach the central
California coast through the day, bringing the first substantial
chances for rain in over a month, strong winds, and chances for
thunderstorms. That part is certain. What makes the forecast
challenging is the fact that with the low coming so close to the Bay
Area and Central Coast, where exactly the low tracks later today,
and whatever upper level support the low can generate, can greatly
impact the magnitude of the impacts from the system. To give an
example of the challenges involved, the HRRR model brings the low
rather close to Point Reyes by 4 AM Wednesday morning, with an
lower level jet supporting strong gusts across the SF Bay Area and
parts of Monterey Bay, while the NAM model brings the low a fair
distance away from Pigeon Point in southern San Mateo County by 4
AM Wednesday morning, cutting out the upper level support and
producing less intense gusts across the Bay Area. Needless to say,
this makes for a lower confidence forecast than typical for
something arriving within the day or so, and a complex situation
not only for the actual forecast, but in messaging the potential
impacts. What follows is a element-by-element treatment of the
impactful weather across the region, arranged in a roughly
decreasing order of confidence.
As previously mentioned, the low pressure system will bring the
first substantial rainfall to the region in over a month, with the
rainfall starting sometime this afternoon or evening across the
region. The southerly flow associated with the incoming system will
bring in a long, thin plume of moisture that does come in from the
subtropical waters near Hawaii, but is expected to quickly push
through the area and progress down the coast into southern
California. The setup of the low will favor the Santa Cruz and Santa
Lucia ranges, where rain totals of 2 to 4 inches are expected
through Thursday morning. This setup also tends to enhance the rain
shadow impacts commonly seen in the Livermore, San Jose, and Salinas
Valley regions, and will also occur in the valleys of Sonoma County
courtesy of the orientation of the incoming flow. Those areas could
see around half an inch of rain, give or take a tenth, for the same
time period. For the rest of the Bay Area and the immediate Monterey
Bay region, rain totals will hover around an inch, maybe up to an
inch and a half in the higher elevations. For context to all of
this, Downtown San Francisco reported 2.65 inches of rain in the
first 7 days of 2026, but has since recorded 0.15 inches since
January 8.
The low pressure system is also expected to bring strong winds to
the region, although how impactful those will be is a little
uncertain due to the aforementioned differences in how the models
are treating the track of the low and any upper level support. The
default National Blend of Models is running closer to the lower end
of the model envelope, so I have blended in the HRRR to bump up the
expected wind speeds and gusts across the region. A Wind Advisory
has been issued across Monterey and San Benito counties for 4 PM
today through 4 AM Wednesday morning, due to southerly wind gusts up
to 40-50 mph, with the highest gusts expected along the Big Sur
Coast and the ridgelines across the Santa Lucias and the interior
mountains, but even within the northern Salinas Valley wind gusts up
to 40-45 mph are in the current forecast. The SF Bay Area and Santa
Cruz County are the areas with the most uncertainty as of this time.
The current forecast brings widespread wind gusts of 20 to 30 mph
across the region with stronger gusts up to 40 mph along the coast
and at the ridgelines. This is very much subject to change depending
on the track of the low and the evolution of any upper level support
that accompanies it.
Finally, there is a slight chance of thunderstorm development across
the region this afternoon into Wednesday associated with the low
pressure system. This is possibly the most uncertain part of the
forecast. On one hand, lapse rates are steep across the region, and
K Index values of 30-32 degrees C support the idea of scattered
thunderstorms being possible. On the other hand, widespread cloud
cover will tend to limit solar heating, limiting the chances for
lift, which is one of the ingredients that are necessary for
thunderstorms to form. If thunderstorms do form, lightning,
localized strong gusts, locally heavy rainfall, and small hail are
the main risks.
By Wednesday, the low will weaken and meander somewhere off the Bay
Area coastline, with cold core showers continuing through the day.
Showers linger into Thursday morning, and begin to diminish
around midday into the afternoon.
&&
.LONG TERM...
Issued at 211 AM PST Tue Feb 10 2026
(Thursday night through Monday)
Behind the low pressure system, upper level ridging will develop
late Thursday into Friday, bringing us a drier spell and slightly
warmer temperatures to end the work week. An upper level trough
returns to the West Coast beginning on Saturday, marking the return
of a wetter pattern to the region. As the previous forecaster noted,
weaker surface features will result in less impactful weather and a
greater chance of beneficial light to moderate rainfall across the
region. The upper level trough continues to deepen for the early
part of next week, causing the cool and wet pattern to persist for
the Bay Area and Central Coast.
&&
.AVIATION...
(12Z TAFS)
Issued at 323 AM PST Tue Feb 10 2026
Mid- to high level clouds across the region through the morning
hours. Southerly winds will build through the afternoon hours in
advance of a low pressure system coming close to the California
coast before weakening and meandering overnight into Wednesday,
bringing rain across the region. Showers will arrive to the region
around 20-22Z, with steadier rain expected this evening through the
end of the TAF period. LLWS is possible across the region, although
the forecast magnitudes and confidence in those are not high enough
to include in the TAFs at this time. A slight chance of
thunderstorms will arrive this afternoon lasting through Wednesday,
but confidence is too low to include in the TAFs at this time.
Confidence in wind direction and speeds across the SF Bay Area
terminals is moderate, and can vary based on the strength and
location of the incoming low; pilots should monitor future TAF
amendments for updated information.
Vicinity of SFO... VFR with mid- to high level clouds and light
southeast winds through the morning, with winds beginning to
increase this afternoon. Confidence in wind speeds is moderate and
can depend on how the low evolves. Showers arrive to the terminal
area around 21-22Z with steadier rainfall expected to arrive in the
evening hours.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals... VFR with mid- to high level clouds and
light winds through the morning. Winds increasing this afternoon
with the approach of the low pressure system, but confidence in the
wind speeds and directions is moderate, especially at MRY where
local effects could shield the terminal from the strongest winds. In
that case, LLWS is possible and even if the magnitude does not reach
the threshold to include in the TAF, bumpy takeoffs and landings are
expected. Showers are expected to come into the region sometime
today, but confidence in timing is low to moderate as high
resolution models disagree.
&&
.MARINE...
(Today through Sunday)
Issued at 323 AM PST Tue Feb 10 2026
A low pressure system currently about 500 nm west of San
Francisco continues to move eastward into the afternoon. Southerly
winds will increase ahead of the incoming storm with gale force
gusts possible south of Pigeon Point this afternoon through
Wednesday morning, with the highest confidence between Point Sur
and Point Piedras Blancas, along with periods of rain and isolated
thunderstorms that will last through Wednesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 4 PM this afternoon to 4 AM PST Wednesday for
CAZ516>518-528-530.
PZ...Small Craft Advisory from 9 AM this morning to 9 PM PST
Wednesday for Mry Bay.
Small Craft Advisory from 9 PM this evening to 9 AM PST
Wednesday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
Reyes 10-60 NM.
Small Craft Advisory from 3 PM this afternoon to 3 PM PST
Wednesday for Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory from 9 AM this morning to 3 PM PST this
afternoon for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Gale Warning from 3 PM this afternoon to 9 AM PST Wednesday for
Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
Blancas 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 9 AM PST
Wednesday for Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...DialH
MARINE...DialH
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Prepared by Boulder-Creek.com Weather at: Tue Feb 10 04:30:04 PST 2026
From the National Weather Service
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