Technical NOAA Weather Discussion

FXUS66 KMTR 182053
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1253 PM PST Sun Jan 18 2026

...New SHORT TERM, LONG TERM...

.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...
(18Z TAFS)
Issued at 902 AM PST Sun Jan 18 2026

Fog and stratus continues to mix out across the North and East 
Bay valleys with lingering impacts at CCR for the next couple of 
hours, but the TAF sites remain VFR through the day. Winds will 
remain light to gentle with a weak onshore breeze near the coast 
and offshore winds persisting inland. Fog and stratus return to 
the North and East Bay valleys tonight with haze expected at LVK. 
High resolution model data depicts some chance for stratus 
development in the San Francisco Bay, but this is a low confidence
forecast at this time.

Vicinity of SFO... VFR through the day. High resolution model 
output is attempting to place a patch of stratus within the San 
Francisco Bay, but impacts to the terminal are highly uncertain 
and opted to leave the VFR TAF intact for now. Chances for stratus
diminish after 18-21Z on Monday morning. Winds remain light with 
offshore flow predominant through the afternoon until mild onshore
flow develops late this evening.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... VFR through the TAF period. Light 
westerly winds through the afternoon and evening, with breezy 
valley drainage winds developing overnight.

&&

.MARINE...
(Today through Friday)
Issued at 837 AM PST Sun Jan 18 2026

Gentle to moderate northeast to east breezes continue across the 
San Pablo Bay, the Delta, and through the Golden Gate through 
Wednesday while 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 and west. 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...DialH
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Sun Jan 18 14:30:03 PST 2026
From the National Weather Service