FXUS66 KMTR 240447
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
947 PM PDT Sat May 23 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1200 AM PDT Sat May 23 2026

 - Diurnally driven onshore winds during the afternoon and early
   evening through the early part of next week

 - Gradual cooling trend begins today with seasonal temperatures
   for the upcoming weekend and cooler temperatures early next
   week, followed by warming into the mid week

&&

.SHORT TERM...
Issued at 1028 AM PDT Sat May 23 2026
(This afternoon through Sunday)

Another deep marine layer setup with plenty of cloud cover pushing 
inland this morning. The passing weak low pressure will keep stratus
mixing around the coast, but the areas inland will see the lower 
clouds erode quickly in the sun.

The North Bay looks to keep cloud cover longer than previous days 
due to this low, leading to a delayed warm up for the interior 
valleys and overall cooler conditions. 

Highs today will range from the 50 along the coast, 60s for areas 
more inland, 70s for the more interior areas, and into the lower 80s 
for the far interior. This will be coupled with a fair amount of 
humidity retention during the day, and great recoveries overnight. 
The deep marine layer and more of and inland push of the marine air 
will keep most of the overnight lows in the 50s, with only the far 
interior falling into the 40s.

Sunday will offer largely similar conditions, with slightly earlier 
clearing times for that inland North Bay cloud cover. Overall high 
temperatures will be slightly cooler, but only by a few degrees.

&&

.LONG TERM...
Issued at 1028 AM PDT Sat May 23 2026
(Sunday night through next Friday)

The marine layer deepens into Sunday night and will push even 
farther inland by Memorial Day, leading to widespread cloud cover. 
This will also cause slower clearing for the interior, and the 
potential for little to no clearing along the coast. Expect cool 
coastal conditions under cloudy skies with highs in the 50s. Then the 
areas slightly inland will hover around the mid to lower 60s, and 
the far interior will be in the 70s. Only a few portions of the far 
interior look to break 80.

The next pattern change looks to arrive Tuesday with a low pressure 
moving down the coast. Longer models have slight disagreements on 
the track of this low, and unfortunately those differences affect 
the Bay Area a good amount. If this low pushing inland to the north 
of the Bay Area, dry off shore flow will cause a jump up in 
temperatures, not to hazardous levels, but a notable increase. If 
the low focuses over the SF Bay, chances for drizzle along with 
continued cooling. The there's a chance the low builds far inland and 
becomes a cut-off low, giving a uniform, yet weaker, offshore flow. 
The current forecast follows the first resolution listed, leading to 
a warmer Tuesday for the Bay Area, but continued cooling for areas 
to the south. This will be followed by a warming and drying trend 
for the rest of the work week. Luckily, after that initial jump in 
temperatures, the rest of the warming trend looks to be gradual. But 
much can change in the mid to long term forecast, so be sure to keep 
checking in!

&&

.AVIATION...
(06Z TAFS)
Issued at 930 PM PDT Sat May 23 2026

Bay Area terminals and South Bay terminals will continue to be 
VFR until after midnight when MVFR cigs will develop and persist 
through late Sunday morning. Guidance provides confidence that 
cigs will mostly be MVFR or hover near it, like KSTS is at 
issuance time. Timing for MVFR to VFR is less confident, with 
guidance suggesting MVFR cigs may persist into Sunday afternoon. 
Breezy onshore flow will persist through the TAF period for near 
coastal sites.

Vicinity of SFO...VFR will continue until after midnight when MVFR
cigs are expected to develop and persist through late Sunday
morning. Confidence on timing is better for KSFO and KOAK than
other sites. Breezy onshore flow will persist through the TAF
period.

SFO Bridge Approach...Similar as SFO.

Monterey Bay Terminals...MVFR cigs will persist through at least
late morning, however there is a chance that MVFR cigs persist
through the entire TAF period with breezy onshore flow as well. 
Another otter eddy is expected to develop just offshore of the 
North Bay early Sunday morning, but then drift farther offshore 
and north with Monterey Bay not seeing any influence and potential
help in clearing.

&&

.MARINE...
(Tonight through next Friday)
Issued at 930 PM PDT Sat May 23 2026

Light breezes and diminished seas will persist through through
Tuesday. Strong northwesterly winds from a developing system set
to arrive on Tuesday will result in building rough seas for the
second half of next week.

&&

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

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...JM
MARINE...JM

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Prepared by Boulder-Creek.com Weather at: Sun May 24 00:30:04 PDT 2026