Technical NOAA Weather Discussion

FXUS66 KMTR 151027
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
227 AM PST Thu Jan 15 2026

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

.KEY MESSAGES...
Updated at 225 AM PST Thu Jan 15 2026

 - Today offers the warmest temperatures of the forecast, with
   highs slowly cooling over the weekend

 - Morning fog across the delta and interior valleys

 - Elevated risk for sneaker waves and rip currents at Pacific 
   coast beaches 


&&

.SHORT TERM...
Issued at 225 AM PST Thu Jan 15 2026
(Today and tonight)


Fairly similar conditions to the previous night so far with slightly 
more consistent fog in the delta as well as in the North Bay 
Valleys. The fog around the Russian River in Sonoma Co looks to be 
more uniform than the previous night, and is more defined on 
satellite. This could hint at the fog lasting longer into the 
morning than the last few days. 

After the fog clears, the region is set for another sunny day with 
this afternoon offering the warmest temperatures in the forecast. 
Highs around the Bay Area will mostly be in the 60s with a few 70s 
possible in the more interior areas. The Santa Cruz mts and southern 
Santa Clara Valley will see more 70-75 degree temps, but Monterey 
and San Benito counties will see widespread 70s. There is the 
potential for a few interior areas in southern Monterey Co to break 
80 this afternoon. Temperatures will be quick to cool after sunset 
with the mostly dry airmass allowing for the warmest (and driest) 
valleys this afternoon to fall back into the mid to low 40s 
overnight. Some of the mountains will experience a weak thermal 
belt, leading to lows in the mid 50s among the peaks.

There wasn't much to tune in the overnight forecast package, aside 
from adjusting the mid to higher terrain winds. The national blend 
seems to be struggling with keeping up with some of those higher 
elevation breezes, so some of the local WRF and the NAM12 was added 
to the mix. Otherwise, the forecast remains on track.


&&

.LONG TERM...
Issued at 225 AM PST Thu Jan 15 2026
(Friday through Wednesday)


There hasn't been much in the way of changes in the mid to long term 
forecast. The ridge of high pressure narrows into the weekend, and 
allows for some slight cooling in high temps, while morning lows 
don't really see much movement. The orientation of the ridge could 
allow for a very weak onshore flow at the immediate coast in the 
late weekend. That, along with a slight easing of pressure shows 
signs for a return of a very shallow marine layer by Sunday. The 
marine layer and a feed of Tule Fog could offer some foggy mornings 
Sunday and into the next work week. However, the lingering dry 
conditions along with some thermal interference from passing high 
clouds could limit fog development. So that'll be something that 
will need finer tuning as the higher resolution models come into 
range. 

The trend of cooling daytime temperatures looks to continue through 
the next work week, with overnight lows only seeing slight 
variations.


In the long, long-term forecast, models are coming to better 
agreement on the breaking of our current ridge pattern toward the 
end of the next work week. A strong trough deepens from the north, 
with its axis falling well to our east, but it looks to be enough to 
flatten the ridge over the west coast. Some model outputs place a 
weak low or a cold front through the area during this flattening, 
which could bring some rain. It won't be heavy rain by any means 
according to these models, but other models are placing the weak low 
much farther inland, which could mean stronger offshore winds and 
increased dry conditions. This all to say that while the longer term 
forecast starts to show a slightly clearer picture, there can still 
be some interesting variations that could lead to very different 
weather. So be sure to keep checking as more updates roll in!

&&

.AVIATION...
(06Z TAFS)
Issued at 848 PM PST Wed Jan 14 2026

Largely a persistence forecast tonight. Which, based on last
night, have removed most mention of reduced vis from TAFs. The  
exception is North Bay terminals and KHAF where FG (KSTS) and HZ 
(coastal) will result in reduced vis through the overnight hours. 
Once again low confidence in any Tule fog impacts for areas in the
interior East Bay, but moderate-high confidence in VFR elsewhere.

Vicinity of SFO...VFR through the TAF period with a slight chance
of low stratus encroaching from the Bay overnight tonight.
Depicted in TAF with FEW cloud group, but capped at FEW to convey
low confidence of coverage affecting terminal. Otherwise light
offshore NE flow continues.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Light offshore NE flow continues.

&&

.MARINE...
(Today through Tuesday)
Issued at 225 AM PST Thu Jan 15 2026

Gentle to moderate northerly breezes will veer through the morning
to become offshore through Saturday before northerly winds  return
Sunday. Moderate seas will prevail through the week with  the
exception of the northwestern portion of the waters where  rough
seas are expected today.

&&

.BEACHES...
Issued at 338 AM PST Wed Jan 14 2026

Hazardous beach conditions return to all Pacific Coast beaches
this morning and persist through tomorrow. Hazards include 
sneaker waves, strong rip currents, and large breaking waves. 
Sneaker waves are potentially deadly waves that suddenly surge 
much farther up the beach than expected, overtaking the unaware. 
They can sweep beach-goers into the ocean, roll logs and heavy 
debris along the beach, knocking over or pinning down unsuspecting
beachgoers, and can result in cold water immersion, which can be 
deadly with sea surface temperatures in the 54 to 57 degrees 
range. Remain out of the water, stay off of waterside 
infrastructure such as jetties, piers, and rocks, and never turn 
your back on the ocean.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through this evening for CAZ006-505-509-
     529-530.

PZ...None.
&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...Behringer
MARINE...Sarment

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Prepared by Boulder-Creek.com Weather at: Thu Jan 15 02:30:02 PST 2026
From the National Weather Service