FXUS66 KMTR 161154
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
354 AM PST Fri Jan 16 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1241 AM PST Fri Jan 16 2026

 - Patchy dense fog in the Valleys Friday morning

 - Dry weather and mild temperatures continue

&&

.SHORT TERM...
Issued at 1241 AM PST Fri Jan 16 2026
(Today and tonight)

The 00Z sounding found a near record temperature at 850 mb (16.6 C 
vs 16.8 C, avg: 7.4 C). This is leading to pretty dramatic thermal 
belting, with warm air in the mountains and cold air settling in the 
valleys. Healdsburg is currently 39 F, while less than 5 miles 
away, the Healdsburg Hills are reporting 70 F at 1700 ft. The 
cold valley air is reaching saturation as the temperatures drops 
to the dew point. Patchy fog is being reported across the valleys.
The coverage is spotty and highly dependent on the wind speed. 
Over the next several hours the coverage should continue to expand
and become more resilient as the cloud layer deepens in the North
Bay Valleys. The Salinas Valley is a little more tricky as mixing
from increasing drainage flow down the valley will counter-act 
further radiational cooling. It's difficult to say which effect 
will win, but we expect the Salinas Valley fog to be thinner, more
patchy, and clear sooner than the calmer North Bay Valleys. After
the fog clears we are in for another beautiful day with clear 
skies and mild temperatures.

&&

.LONG TERM...
Issued at 1241 AM PST Fri Jan 16 2026
(Saturday through Thursday)

Nice, dry weather will continue for the next several days. Some high 
clouds will roll in from the south this weekend, which should 
moderate both max and min temperatures a bit, while producing some
colorful sunrises and sunsets. Ensemble cluster analysis shows 
high confidence that the strong ridge at 500 mb over the Gulf of 
Alaska will gradually erode over the next 5-7 days. The 
uncertainty grows beyond the middle of next week, but either zonal
flow or a troughing pattern seems more likely than continued 
ridging. While the change at the surface will be subtle, onshore 
flow will gradually return, high temperatures will cool a few 
degrees, and coastal clouds will start creeping back in by the 
middle of next week. If the pattern becomes more active, there is 
a chance for very light rain as early as next Thursday, with a 
stronger signal for more substantial precipitation by the middle 
of the following week (end of January).

&&

.AVIATION...
(12Z TAFS)
Issued at 353 AM PST Fri Jan 16 2026

VFR continues for most TAF sites through the TAF period. The 
exceptions will be STS, APC, and HAF which will see fog this morning 
and again in tonight for APC and STS. Winds will mostly say light 
through the TAF period with directions being mostly variable, 
although some localized effects will determine the wind directions 
at a few of the TAF sites. 

Vicinity of SFO...VFR through the TAF period. Expect mostly light 
and variable winds through much of the day before winds turn 
northerly 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. East to 
southeast winds last through into the afternoon before winds turn 
northerly. Winds turn easterly and southeasterly again into the 
night.

&&

.MARINE...
(Today through Wednesday)
Issued at 353 AM PST Fri Jan 16 2026

Mostly light winds are expected across the waters through the
forecast period. Some locally breezy winds will be possible along
favored gaps and around the Golden Gate, but theses winds do not
look to be widespread. Seas become more moderate into the second
half of the next work week with long period swells arriving.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Dense Fog Advisory until 9 AM PST this morning for CAZ506.

PZ...None.
&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Murdock
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Fri Jan 16 04:30:02 PST 2026