FXUS66 KMTR 050537
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
937 PM PST Sun Jan 4 2026
...New AVIATION, MARINE, BEACHES...
.KEY MESSAGES...
Updated at 129 PM PST Sun Jan 4 2026
- Rain coming to an end today, mostly dry tonight.
- Another round of light-to-moderate rain expected Monday morning
with scattered showers during the afternoon.
- Light scattered showers into midweek, then high confidence in
fair weather the wrap up the week into the weekend.
&&
.UPDATE...
Issued at 758 PM PST Sun Jan 4 2026
Isolated rain showers are still ongoing across the region, but
activity continues to diminish in coverage and intensity. No new
flooding impacts are expected tonight, but ponding on roadways
and elevated creeks/streams can still be expected. Allow extra
time in the morning if you are commuting as this is when
widespread rainfall returns. Flooding of urban, low-lying, and
poor drainage areas as well as flashy creeks/streams can be
expected tomorrow. Shallow landslides will also be possible. In
addition to flooding from freshwater, we also have one more day of
coastal flooding from King Tides tomorrow afternoon along the
bayshore of the San Francisco and San Pablo Bays. If you encounter
flooded roadways: turn around, don't drown!
Sarment
&&
.SHORT TERM...
Issued at 129 PM PST Sun Jan 4 2026
(This evening through Monday)
Quite the episode of rain this morning here at NWS MTR. A few
areas from the Monterey Peninsula to Hollister reported 1-2 inches
of rain this morning with Monterey Airport coming in at 2.15"
since midnight. Elsewhere around the Bay Area reports range from
about 0.5-1" depending on where you are north to south and in
relation to rain shadowing terrain. Some lingering rain showers in
the vicinity of the SF Bay are moving out this afternoon, and most
people should see the sun at some point this afternoon/evening.
Moving on to tomorrow, we're anticipating another round of
rainfall beginning in the pre-dawn hours for the North Bay and Bay
Area, then the Monterey Bay and Central Coast around sunrise. This
does seem to be a more progressive line of showers as opposed to
the training showers that we had this morning. However, with soils
at or near saturation in some areas, flooding concerns will arise
easily. We are NOT expecting any widespread, damaging winds with
tomorrow's system, but as mentioned regarding the state of the
soil, trees will be more likely to fall under lesser magnitude
winds than would normally be required. After the main band of
morning rainfall, we'll see some scattered showers into the
afternoon with a small potential for an isolated thunderstorm over
the waters. The showers at this point should be mostly
unproblematic outside of one or two isolated strong showers that
may exacerbate already existing flooding impacts. In terms of
thunderstorms, there is some instability into the afternoon
hours which could lead to more vigorous updrafts over the waters,
but don't really see the threat really making it very far onto
land. To that point, the wind field is nearly uniform up to almost
500 mb, so there will be very little, if any, shear to support
persistent updrafts. The primary threat continues to be isolated
nuisance flooding and shallow landslides.
&&
.LONG TERM...
Issued at 129 PM PST Sun Jan 4 2026
(Monday night through next Saturday)
Conditions dry out Monday night giving way to mostly clear skies
Tuesday with just a few lingering light showers. Beyond this and
through the rest of the week the story turns to cold overnight
temperatures and absolutely gorgeous, albeit chilly, afternoons.
Ensemble cluster analysis strongly supports broad, high amplitude
ridging in the long term. For overnight lows, it looks like the
coldest period will be Thursday through Monday mornings with the
peak cold being Friday morning (Thursday night) where widespread
30s are likely inland with mid-to-lower 40s along the coast.
&&
.AVIATION...
(06Z TAFS)
Issued at 937 PM PST Sun Jan 4 2026
Generally VFR conditions with mid- to high level clouds across the
region, with isolated showers persisting early tonight. Widespread
rain returns after Monday morning with generally moderate rain
rates, particularly for the North Bay terminals, localized heavy
rain, and diminished visibilities expected. Southerly flow continues
through the TAF period, with winds remaining light overnight with
periods of gusty winds expected as the main rain band comes through.
Visibilities and ceilings will drop below the TAF forecast if a
strong shower moves over a particular terminal.
Vicinity of SFO... VFR with mid- to high level clouds through the
next few hours before light to moderate rain returns Monday morning,
when conditions hover near the MVFR-VFR threshold. Showers will
again diminish in intensity Monday evening through the end of the
TAF period as ceilings lift above MVFR thresholds. Visibilities and
ceilings will drop below the TAF forecast if a strong shower moves
over SFO.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals...Light winds overnight as generally VFR-MVFR
conditions and isolated to scattered showers continue. Southerly
winds build overnight as a frontal rain band approaches, with the
main impacts arriving Monday morning, including gusty southeast
winds and light to moderate rain. Rain intensity should diminish
Monday afternoon through and after the end of the TAF period. If
more intense showers develop over the region, expect visibilities
and ceilings to drop below the forecast within the TAF.
&&
.MARINE...
(Tonight through next Saturday)
Issued at 937 PM PST Sun Jan 4 2026
Isolated to scattered showers continue overnight with widespread
rainfall and a slight chance for thunderstorms developing on
Monday. Seas remain moderate to rough tonight under southwesterly
winds with strong to gale force gusts. Winds diminish by early
next week but are expected to build again, along with seas, during
the late week as long period northwesterly swell returns.
&&
.BEACHES...
Issued at 937 PM PST Sun Jan 4 2026
A Coastal Flood Advisory has been extended through 3 PM Monday
for the San Francisco Bay and San Pablo Bay due to Perigean
spring tides (king tides) and up to 1 foot of storm surge. The
combination of these factors will bring minor to moderate coastal
flooding to the low-lying areas near shorelines and tidal
waterways during high tide on Monday late morning and early
afternoon.
High tide is expected to be 1.2 ft above normal at 12:08 PM
Monday. These predictions include up to 1 foot of storm surge
that will enhance the astronomical tide and flooding threat. High
tide varies up to 90 minutes earlier or later along the Pacific
Coast and through the San Francisco Bay, respectively.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 10 PM PST this evening for CAZ006-
505-509-529-530.
Coastal Flood Advisory until 3 PM PST Monday for CAZ006-506-508.
PZ...Small Craft Advisory from 3 AM to 9 PM PST Monday for Mry Bay.
Small Craft Advisory until 3 PM PST Monday for Pt Arena to Pt
Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PST Monday for Pigeon Pt to Pt
Pinos 0-10 nm.
Small Craft Advisory until 9 AM PST Monday for Pt Arena to Pt
Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Gale Warning from 9 AM to 3 PM PST Monday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Small Craft Advisory from 9 AM to 9 PM PST Monday for Pigeon Pt
to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...DialH
MARINE...DialH
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Prepared by Boulder-Creek.com Weather at: Mon Jan 5 00:30:03 PST 2026
From the National Weather Service
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