FXUS66 KMTR 190109
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
509 PM PST Sun Jan 18 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1251 PM PST Sun Jan 18 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 1251 PM PST Sun Jan 18 2026
(This evening through Monday)

Temperatures continue to warm as mostly sunny sky conditions have
returned to the region. However, there are still high clouds 
streaming in from the northwest. As such, temperatures are likely 
to warm into the low to upper 60s across the North Bay, East Bay, 
and greater San Francisco Bay Area. Across the Central Coast, 
temperatures are likely to warm into the low to mid 70s. 

Tonight, look for tule fog to return to the interior East Bay 
Valleys and Delta (similar timing as the previous nights) and 
continue through midmorning on Monday. Fog may also impact the 
North Bay Valleys in response to fog development in the Russian 
River Valley and/or tule fog advecting in from the east.

Monday's afternoon temperatures will be similar to those today 
(Sunday) as the region continues to be under the influence of high
pressure. This ridge axis extends all the way up to just off of 
the British Columbia coast. However, high clouds will persist over
the region through at least midweek.

&&

.LONG TERM...
Issued at 1251 PM PST Sun Jan 18 2026
(Monday night through next Saturday)

By mid to late week, troughing will develop out over the north 
central Pacific. This feature is forecast to develop a cut-off 
upper level low that will gradually approach the region late in 
the week. However, there does not appear to be much of a moisture 
source associated with it, so rainfall has been pushed back until 
at least Monday, January 26th. With that said, the low pressure 
system aloft will at least cool temperatures down to near seasonal
averages after a prolonged period of very warm afternoon 
temperatures. Thus, we will have to wait a bit longer for much 
needed rainfall to return.

&&

.AVIATION...
(00Z TAFS)
Issued at 508 PM PST Sun Jan 18 2026

VFR continues for most TAF sites through the TAF period. The 
exceptions will be STS and APC which will see fog overnight as well 
as fog and haze possible at LVK. Winds will mostly say light through 
the TAF period with directions being mostly variable. Some sites 
along the coast will see northwest Monday afternoon, while others 
stay variable, and LVK goes easterly.

Vicinity of SFO...VFR through the TAF period. Expect mostly light 
and variable winds through the night and much of the Monday before 
winds turn northwesterly in the late afternoon, but become variable 
again into the night. 

SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR through the TAF period. West winds 
become more variable into the night. Southeast winds build at SNS in 
the late night and last into Monday afternoon before turning 
northwesterly in the mid afternoon. Winds at MTR look to stay light 
and variable through the end of the TAF period.
&&

.MARINE...
(Tonight through next Saturday)
Issued at 508 PM PST Sun Jan 18 2026

Gentle to moderate northeast to east breezes persist across the
San Pablo Bay, the Delta, and through the Golden Gate through
Wednesday as light to gentle northeast to north winds continue
across the rest of the coastal waters. Later this week, the ridge
should break down as a weak cutoff low approaches, allowing winds
to increase and shift to the northwest. Low seas up to around 6
feet continue through the middle of the week as a northwest swell
builds.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Murdock
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Sun Jan 18 18:30:03 PST 2026