FXUS66 KMTR 191120
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
320 AM PST Mon Jan 19 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 246 AM PST Mon Jan 19 2026
- Dry weather, cool mornings, and warm afternoons this week
- Morning fog across the Delta, North Bay Valleys, and interior
East Bay Valleys
&&
.SHORT TERM...
Issued at 246 AM PST Mon Jan 19 2026
(Today and tonight)
Patchy fog is developing in the North Bay Valleys with intermittent
reports of dense fog (1/4 statute mile visibility or lower)
coming in from KSTS (Santa Rosa Airport) and KDVO (Novato/Gnoss
Field Airport). Will hold off on a Dense Fog Advisory for now as
the areas of dense fog are localized/not widespread on the webcam
footage. If anyone is commuting in the North Bay Valleys, East Bay
Valleys, or along the San Pablo/Suisun Bay and Delta areas this
morning, be aware of the potential for dense fog, be prepared for
sudden changes in visibility, and remember to slow down.
High pressure remains the name of the game. A ridiculously resilient
ridge remains fixed over the West Coast with temperatures running
anywhere from 5 to 15 degrees above normal for this time of year.
High temperatures on Sunday were generally in the mid to upper 60s
across the lower elevations of the Bay Area, upper 60s to low 70s
across the higher elevations, and low to upper 70s across the
Central Coast. The temperature distribution for today looks to be
fairly similar with highs in the mid to upper 60s across the Bay
Area and upper 60s to mid 70s throughout the Central Coast. Guidance
shows a shallow (500 ft) marine layer developing tonight which may
bring additional fog and low clouds to portions of the coastline
tonight. Winds remain light and offshore through midweek.
&&
.LONG TERM...
Issued at 246 AM PST Mon Jan 19 2026
(Tuesday through Sunday)
Ridging sticks around through at least midweek before an upper level
trough pushes in late Wednesday into Friday. This upper level trough
will develop as a cut-off low and move southwards along the
California coastline late this week. Unfortunately, this system
looks to be dry with no rain expected from this system. PWAT
values are between 0.7"-0.8" with a slightly stronger moisture tap
entering southern California (where models show the potential for
light rain). In the wake of this cut-off low, upper level ridging
redevelops over the West Coast this weekend into next week. Rain
lovers should not fully despair yet as models do signal some
potential for rain to return late January/early February. The
ECMWF shows some potential for light rain in early February with
deep upper level troughing pushing into the West Coast. Models
have consistently showed something developing late January/early
February but the timing continues to be pushed back. The timing of
the return of rain will become more clear as we get closer in
time to late January/early February.
While we aren't expecting any rain with this upper level trough, it
will bring in cooler air amd a return of more seasonal
temperatures. High temperatures remain warm on Tuesday with highs
in the mid 60s to low 70s (approximately 5 to 10 degrees above
normal). Temperatures cool into the upper 50s to mid 60s
Wednesday into the weekend as the ridge breaks down and cooler
air arrives with the upper level trough. As the ridge rebuilds
over the weekend, temperatures may warm by a few degrees but
overall remain seasonal in the low to mid 60s. Winds shift
onshore mid to late week as the upper level low moves down the
coastline but they will shift offshore again by the weekend as the
ridge rebuilds. Localized dense fog continues nightly across the
interior valleys through the weekend with the potential for more
fog to become more widespread across the interior valleys starting
Thursday night.
&&
.AVIATION...
(12Z TAFS)
Issued at 315 AM PST Mon Jan 19 2026
Persistence forecast. High confidence in intermittent FG/BR invof
KSTS and KAPC. Tule fog along the Delta will likely impact
interior East Bay terminals such as KCCR and KC83. Otherwise VFR
prevails through the period for all other terminals. Winds remain
light and variable.
Vicinity of SFO...VFR. Winds light and variable.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Winds light and variable. SE
drainage flow out of the Salinas Valley during the overnight and
morning hours.
&&
.MARINE...
(Today through Saturday)
Issued at 315 AM PST Mon Jan 19 2026
Light to gentle breezes continue across the waters this week.
Slight increase in winds over the outer waters by late week as the
large scale weather pattern begins to shift. Moderate period
northwesterly swell enters the waters mid week, peaking Tuesday
night into Wednesday morning.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Behringer
MARINE...Behringer
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Prepared by Boulder-Creek.com Weather at: Mon Jan 19 06:30:02 PST 2026
From the National Weather Service
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