FXUS66 KMTR 121905
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1205 PM PDT Sat Sep 12 2026
...New SHORT TERM, LONG TERM, FIRE WEATHER...
.KEY MESSAGES...
Updated at 1201 PM PDT Sat Sep 12 2026
- Breezy onshore winds this afternoon through Sunday afternoon
- Temperatures near seasonal averages through this upcoming week
- Dry, offshore winds are forecast for the higher terrain Sunday
night into Monday night
&&
.SHORT TERM...
Issued at 1201 PM PDT Sat Sep 12 2026
(This evening through Sunday night)
As mostly sunny skies have returned to the region, we are
expected temperatures to warm into the 60s to lower 70s along the
northwest facing coastal locations and low to upper 70s around the
Santa Cruz region, bayshore, and coastal adjacent valleys.
Meanwhile, interior valleys are forecast to reach into the upper
70s to mid 80s with the warmest interior valleys of the Central
Coast reaching into the low 90s. Onshore wind gusts are forecast
to reach between 25 to 35 mph in the favored gaps, passes, and
coastal/higher elevation regions gusts up to 45 mph. This is ahead
of a dry frontal boundary which is expected to move through the
North Bay late this evening and then across the Central Coast
Sunday morning. Moderate to high confidence that low clouds will
not spread inland overnight into Sunday morning (patchy at best),
similar to this morning. However, the marine layer looks to hover
between 1,500 and 2,000 feet through the night.
By Sunday afternoon, the front is forecast to be south of the
region with cooler temperatures in the higher elevations while
slightly cooler for the lower elevations. Onshore winds will
increase once again tomorrow afternoon and evening with gusts
potentially exceeding those forecast for today, but only by 5 to
10 mph. Aloft, a light to gentle offshore breeze (with
occasionally moderate gusts) is forecast to develop in the higher
terrain as the mid/upper level trough axis shifts into the
northern Rockies. These winds are not forecast to be overly
strong, which will help limit fire weather concerns.
&&
.LONG TERM...
Issued at 1201 PM PDT Sat Sep 12 2026
(Monday through next Friday)
The trough axis is forecast to move into northern Plains early next
week, diminishing the offshore wind potential. Lingering troughiness
along the West Coast will maintain cooler than average temperatures
for much of the week ahead. As such, temperatures are forecast to
warm into the 60s to lower 70s along the northwest facing coastal
locations and low to upper 70s around the Santa Cruz region,
bayshore, and coastal adjacent valleys. Meanwhile, interior valleys
are forecast to reach into the upper 70s to mid 80s with the warmest
interior valleys of the Central Coast reaching into the low 90s.
Overnight and morning low clouds are expected to reach inland before
mixing out by the afternoon hours as well through the extended
forecast period.
&&
.AVIATION...
(18Z TAFS)
Issued at 1036 AM PDT Sat Sep 12 2026
VFR across the region with low confidence that stratus will return
tonight. Guidance is showing a largely drier airmass moving in
tonight which is decreasing confidence that we will see widespread
stratus coverage. More favorable conditions for localized
fog/stratus development exist along the coast where buoys are
showing an upwards transfer of heat/moisture from the sea to the
air (SST are warmer than air temperatures above the buoy). Expect
gusty winds today with widespread gusts between 25 to 35 knots.
Locally stronger gusts are possible in areas where terrain
promotes wind funneling.
Vicinity of SFO...VFR through the TAF period. Gusty onshore winds
are expected today with gusts between 25 to 35 knots forecasted
this afternoon into the evening. Winds decrease slightly overnight
but strengthen again by Sunday morning. The SFO-WMC gradient peaks
around +13 mb today which correlates to strong onshore winds.
SFO Bridge Approach...Similar to SFO. Strong onshore winds are
expected this afternoon/evening with gusts to around 35 knots
possible.
Monterey Bay Terminals...VFR. Low confidence that stratus will
return tonight but if it does return it likely will not be until
after 12Z. Given the low confidence, have only included a tempo
for tonight's stratus coverage after 12Z. Gusty onshore winds
peaking around 25 knots are expected today before diminishing
overnight. Breezier conditions are expected again tomorrow but
winds should be weaker than those observed today.
&&
.MARINE...
(Today through Thursday)
Issued at 856 AM PDT Sat Sep 12 2026
Hazardous conditions for small craft prevail this weekend through
the middle of next week. Winds increase today with a strong
breeze to develop by early Sunday and continue into the middle of
next week. Widespread near gale force gusts are likely Sunday into
early Monday with gale force gusts are expected along the inner
waters from Pigeon Point to Point Piedras Blancas, the Monterey
Bay, and in portions of the San Francisco and San Pablo Bays.
Moderate seas will build, becoming rough by Monday in response to
the stronger winds.
&&
.FIRE WEATHER...
Issued at 1201 PM PDT Sat Sep 12 2026
The marine layer was around 1,500 feet in depth per 12Z OAK Upper
Air Sounding. However, stratus coverage did not match the typical
depth this morning and is not likely to again tonight despite the
marine layer forecast to be between 1,500-2,000 feet. A dry
frontal boundary is forecast to move across the Central Coast
tonight and into Sunday morning. Ahead of this boundary, we are
expecting an increase in 925 mb relative humidities which would
lead to higher humidity over the Timber and Plaskett fires
overnight and into Sunday morning. Sunday night into Monday night,
a light to gentle offshore breeze (with occasionally moderate
gusts) is forecast to develop in the higher terrain as the
mid/upper level trough axis shifts into the northern Rockies. As
such, areas above the marine layer often experience nocturnal
drying that will likely continue through early this upcoming week.
RGass
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PDT Sunday for SF Bay N of Bay
Bridge.
Small Craft Advisory from 3 PM to 9 PM PDT Sunday for SF Bay N
of Bay Bridge.
Small Craft Advisory until 3 PM PDT Sunday for Mry Bay-Pigeon Pt
to Pt Pinos 0-10 nm.
Gale Warning from 3 PM to 9 PM PDT Sunday for Mry Bay-Pigeon Pt
to Pt Pinos 0-10 nm.
Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt
Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to
Pt Piedras Blancas 0-10 nm.
Gale Warning from 9 PM this evening to 9 PM PDT Sunday for Pt
Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory from 3 PM Sunday to 3 AM PDT Monday for Pt
Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...Kennedy
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea
Prepared by Boulder-Creek.com Weather at: Sat Sep 12 12:30:03 PDT 2026
From the National Weather Service
|