FXUS66 KMTR 250449
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
949 PM PDT Mon Aug 24 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 128 PM PDT Mon Aug 24 2026

 - Temperatures near to slightly below seasonal averages persist
   within the marine layer

 - Warm, slightly above normal temperatures, and dry conditions 
   continue above 1000 feet

 - Pattern change Friday into the weekend brings cooler
   temperatures and low potential for tropical moisture

&&

.UPDATE...
Issued at 917 PM PDT Mon Aug 24 2026

Coastal stratus has developed and is extending through the
Petaluma Gap, the Golden Gate, and the northern Salinas Valley.
The stratus deck will continue to expand through the overnight
hours before retreating back to the coast Tuesday morning.
Forecast remains on track.

DialH

&&

.SHORT TERM...
Issued at 128 PM PDT Mon Aug 24 2026
(This evening through Tuesday night)

The short term forecast is fairly unchanged as we remain on the 
border of troughing to the north and ridging to the south. Today's 
high temperatures will be in the low to mid 80s across interior 
lower elevations and mid 80s to low 90s across interior higher 
elevations. The interior Central Coast will be slightly warmer with 
highs in the upper 90s to low 100s. Coastal locations remain under 
the influence of a shallow marine layer, approx. 1000 feet, which 
will keep temperatures in the 60s to low 70s. We are expecting 
another early return of stratus along the coast tonight with the 
marine layer remaining between 1000-1200 feet. Ridging will become 
more dominant over the region tonight into tomorrow as the center of 
the ridge shifts slightly westward. This will result in temperatures 
warming by 2-5 degrees compared to today. Practically, this is the 
difference between the interior being in the low to mid 80s to mid 
to upper 80s while the higher elevations stay in the upper 80s to 
low 90s. No real changes to the coastal temperatures. Even with 
temperatures warming slightly, interior temperatures remain seasonal 
across the lower elevations and are only running 5-7 degrees above 
normal across the higher elevations. Coastal locations and areas 
along the SF Bay Shoreline will be seasonal to below normal. With 
similar weather conditions prevailing into the long term forecast, 
we will not be close to any record temperatures this week. Diurnally 
breezy winds are expected along the coast, higher terrain, and 
mountain gaps/passes.

&&

.LONG TERM...
Issued at 128 PM PDT Mon Aug 24 2026
(Wednesday through next Sunday)

Ridging prevails through Thursday with high temperatures in the mid 
to low 90s prevailing across the interior and upper 90s to low 100s 
across the interior Central Coast. Coastal areas experience a slight 
warm up with more locations reaching into the 70s but, overall, stay 
cooler compared to interior locations. Friday into the weekend the 
pattern switches up on us. A deep upper level trough will approach 
the Western US and move inland Friday into the weekend. As the 
trough moves inland we can expect it to bring cooler temperatures 
and breezier winds to the region. Interior highs cool into the 80s, 
across both the higher and the lower elevations, before gradually 
cooling from the 80s into the 70s Saturday through Monday. Coastal 
and SF Bay shoreline temperatures will remain in the 60s to 
potentially the low 70s. Even the interior Central Coast gets in on 
the cooling trend with highs dropping into the upper 80s to low 90s 
by Monday. Gusty onshore winds are expected each afternoon/evening 
Friday into the weekend as the approaching trough tightens the 
surface pressure gradient. Right now, the strongest gusts are 
between 25 to 35 mph with locally stronger gusts possible across the 
marine environment, the higher terrain, and the Altamont Pass. 
Fortunately, the incoming trough should help the marine layer to 
deepen and result in more widespread moist conditions across the Bay 
Area. That being said, it is possible higher elevations will see 
some offshore flow if this trough takes a more inside slider type 
path.

Lastly, the Eastern Pacific Ocean remains quite active in terms of 
tropical activity. As of this morning's NHC update, Tropical Storm 
Iselle and four other areas of potential tropical development were 
all located off of Western Mexico. While Iselle is expected to move 
northwest, staying well out to sea, we are anticipating an increase 
in long period southerly swell across our coastal waters Friday into 
the weekend. The current forecast remains just below criteria for a 
Beach Hazards Statement but this may change as we get closer in 
time. Beachgoers this weekend will need to be aware of the potential 
for sneaker waves and strong rip currents. There is still some 
potential for tropical moisture to be transported northwards as the 
trough arrives this weekend. Currently, models show minimal tropical 
moisture extending into our CWA but this will need to be closely 
monitored as we still have four potential tropical systems brewing 
to our south off of Mexico. The NBM highlights a non-zero (< 5%) 
chance for thunderstorms across our region Friday into the weekend. 
We are also monitoring this closely given uncertainties surrounding 
developing tropical storms across the Eastern Pacific.&&

&&

.AVIATION...
(06Z TAFS)
Issued at 940 PM PDT Mon Aug 24 2026

The marine layer is roughly 1,000 feet deep and well organized. 
As the marine layer makes its nightly push inland, IFR-LIFR 
conditions will be widespread across nearly all of the terminals 
through the night and most of the morning. The visibility is a 
little more uncertain, but some patchy fog is likely. Low clouds 
should start to clear for all but the coastal airports by late 
morning.

Vicinity of SFO...IFR ceilings have arrived and there is a high 
probability they will remain for at least the next 12 hours. There
is a 40% chance that the visibility drops below VFR criteria after
10Z.

SFO Bridge Approach...Similar to SFO, although the ceilings
haven't formed yet and they will clear earlier than the terminal
Tuesday morning.

Monterey Bay Terminals...LIFR ceilings are essentially guaranteed
through the night and most of the morning. While SNS will likely
clear in the late morning, MRY may only see ceilings lift to IFR
in the afternoon before dropping back down to LIFR Tuesday
evening. If it does clear, it probably won't be for more than 6 
hours.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 917 PM PDT Mon Aug 24 2026

The increasing gradient between high pressure over the Eastern
Pacific and lower pressure over California will cause winds to
increase to a fresh NW breeze through the day tomorrow and winds
will remain fresh to strong through the week. A long period
southerly swell around 15 to 17 seconds approaches our coastal
waters by the end of the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM Tuesday to 9 AM PDT Wednesday for 
     Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 
     0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for Pigeon Pt 
     to Pt Pinos 0-10 nm.

     Small Craft Advisory from 9 PM Tuesday to 9 AM PDT Wednesday for 
     Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 
     NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Flynn
MARINE...Flynn

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Prepared by Boulder-Creek.com Weather at: Mon Aug 24 22:30:03 PDT 2026