FXUS66 KMTR 022020
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1220 PM PST Fri Jan 2 2026
...New SHORT TERM, LONG TERM, BEACHES...
.KEY MESSAGES...
Updated at 1218 PM PST Fri Jan 2 2026
- High astronomical tides combined with storm surge will bring
substantial tidal flooding through Sunday
- Strong southerly winds tonight into Saturday morning
- Chance of thunderstorms tonight through the weekend
- Daily rain showers expected through Monday
&&
.SHORT TERM...
Issued at 1218 PM PST Fri Jan 2 2026
(This evening through Saturday)
It has been fairly quite late this morning and is expected to
remain so through the afternoon ahead of our next approaching
system that is due to arrive late this evening and through
Saturday morning. Southerly winds are forecast to increase this
afternoon and remain gusty through at least Saturday afternoon.
Sustained southerly winds of 15-25 mph with gusts up to 50 mph
(locally stronger in the highest elevations) will remain possible
through Saturday afternoon along the coast and in the higher
terrain. Isolated thunderstorms are also possible late this
evening and into early Saturday morning as surface based CAPE
reaches up to 250 J/kg, most notability around the North Bay.
Along with this, as the main rain band moves across the region it
will be capable of producing moderate to heavy rainfall.
Isolated to scattered thunderstorms are likely Saturday a colder
airmass drops southward across the region in wake of the earlier
frontal passage. This is when forecast models suggest 250-750 J/kg
of surface based CAPE. The greatest potential looks to be over
the North Bay were we are expected the higher end of the above
mentioned values will be placed late Saturday morning and into the
evening. Thus, cannot rule out landfalling water spouts across
this region. This is also where there is a Marginal Risk for
severe weather with a general mention from the Storm Prediction
Center across the remainder of the region.
&&
.LONG TERM...
Issued at 1218 PM PST Fri Jan 2 2026
(Saturday night through next Thursday)
Thunderstorm potential will continue into Monday as reinforcing
cold fronts move through the region. The greatest potential
currently looks like early Sunday morning through the afternoon
and again Monday afternoon. Given the breaks between these
systems, we don't currently anticipate widespread flooding.
However, any heavier shower or thunderstorm will be capable of
producing heavy rain, small hail, and the potential for funnel
clouds/water spouts.
Conditions look to remain cool and unsettled through the first
half of next week, yet not nearly as wet as late this week and
into to the weekend. There remain differences in the ensemble
guidance making things difficult to pinpoint this far out.
However, there is good confidence that we will trend drier and
cooler than normal for late next week and into the following
weekend (January 10-11). This is also being captured by the 6-10
day outlook from the Climate Prediction Center.
&&
.AVIATION...
(18Z TAFS)
Issued at 952 AM PST Fri Jan 2 2026
Currently VFR but expect unsettled weather to develop throughout the
day with an atmospheric river arriving tonight. Winds strengthen
late this morning/early this afternoon with gusts peaking between 30
to 35 knots tonight. Locally higher gusts to around 40 knots are
expected along the coastline and within valleys. Rain chances
increase this evening into tomorrow morning with moderate to heavy
rain expected as the main rain band rolls through overnight. There
is some potential for low level wind shear but, in agreement with
the previous forecaster, there looks to be enough mixing downwards
of stronger winds so as to prevent widespread LLWS. After the main
rain band moves through, scattered light to moderate showers are
expected tomorrow morning/afternoon. There is a 15-20% chance of
thunderstorms both within the main rain band and in scattered
showers continuing on Saturday. Visibilities are on the more
pessimistic side in the TAFs with lower visibilities supported by
locally moderate to heavy rain and strong winds. There is the
potential for visibilities to drop even further than currently
listed in the TAF if a particularly strong cell moves over the TAF
site.
Vicinity of SFO...Moderate rain, lowered visibilities, and strong
winds will impact SFO overnight into tomorrow. Winds strengthen this
evening with gusts to around 38 knots expected overnight into
tomorrow. The main rain band will arrive late this evening bringing
moderate to at times heavy rain before transitioning to moderate
showers early Saturday morning. Winds decrease mid Saturday morning
but conditions will remain gusty before strengthening again later in
the day. Guidance indicates some potential for ceilings to lower
below 3000 ft at the end of the TAF period but confidence is low.
SFO Bridge Approach...Strong, gusty winds are expected over the
southern SF Bay which may bring low level wind shear concerns to the
SFO Bridge Approach. Current thinking is that there will be enough
mixing of strong winds within the lower levels of the atmosphere to
reduce LLWS concerns but it remains a possibility. Otherwise,
similar to SFO.
Monterey Bay Terminals...Winds strengthen this afternoon/evening
with gusts to around 30-35 knots expected overnight. Periods of
moderate rain and moderate showers are expected overnight as a
strong cold front passes through the region. Winds decrease by mid
tomorrow morning with showers decreasing from moderate to light.
Visibilities may drop further than currently listed in the TAF if a
strong cell moves directly over the airport. Any additional drops in
visibility are expected to be temporary.
&&
.MARINE...
(Today through Wednesday)
Issued at 904 AM PST Fri Jan 2 2026
Gale force winds have developed over the northern waters and will
spread across the rest of the coastal waters today. Localized
storm force winds are possible tonight across the northern outer
waters. Winds diminish Saturday with gale force winds continuing
for the northern waters and strong to near gale force winds
elsewhere. Moderate rain and a slight chance of thunderstorms
continues through the weekend with light rain expected to
continue through early next week.
&&
.BEACHES...
Issued at 1218 PM PST Fri Jan 2 2026
A Coastal Flood Warning is in effect for the San Francisco Bay
through Saturday. A Coastal Flood Advisory is in effect for the
Pacific Coast and Monterey Bay through Sunday. Perigean spring tides
(king tides) will impact the region through Sunday. This is due to
the combination of the full moon on 1/3, lunar perigee on 1/1, and
perihelion on 1/3. In other words the earth, sun and moon are lined
up and close to each other. In addition to the high astronomical
tide, the incoming low pressure system will bring strong southerly
winds, generating some storm surge, particularly on Saturday
morning. The combination of these factors will bring moderate
coastal flooding to the low-lying areas near shorelines and tidal
waterways during high tide through Sunday.
On Friday, the San Francisco tidal gauge recorded 2.26 ft of
inundation. Looking ahead, high tide is expected to be 2.5 ft
above normal at 10:26 AM Saturday and 1.9 ft above normal at 11:18
AM Sunday. These predictions include up to 1.3 feet of storm
surge that will enhance the astronomical tide and flooding threat.
A reasonable worse case scenario (10% exceedance chance) is 2.7
ft of inundation on Saturday. The all time record is 2.8 ft from
1/27/1983. 2.5 ft hasn't been reached since 1998. 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...Coastal Flood Warning until 2 PM PST Saturday for CAZ006-506-508.
Wind Advisory until 1 PM PST Saturday for CAZ006-502>505-509-512-
514>518-528>530.
Coastal Flood Advisory from 2 PM Saturday to 2 PM PST Sunday for
CAZ006-506-508.
Coastal Flood Advisory until 2 PM PST Sunday for CAZ505-509-529-
530.
PZ...Small Craft Advisory until 3 AM PST Saturday for SF Bay N of Bay
Bridge.
Small Craft Advisory until 9 PM PST this evening for Mry Bay.
Gale Warning from 9 PM this evening to 3 AM PST Saturday for Mry
Bay.
Gale Warning until 3 AM PST Saturday for Pigeon Pt to Pt Pinos 0-
10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-
10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Gale Warning until 9 AM PST Saturday for Pt Pinos to Pt Piedras
Blancas 0-10 nm.
Gale Warning until 3 PM PST Saturday for Pt Arena to Pt Reyes 10-
60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...Kennedy
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Prepared by Boulder-Creek.com Weather at: Fri Jan 2 12:30:02 PST 2026
From the National Weather Service
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