FXUS66 KMTR 242029
AFDMTR

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

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

.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

&&

.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...
(18Z TAFS)
Issued at 1126 AM PDT Mon Aug 24 2026

A blanket of stratus has retreated to the coastline resulting in VFR 
conditions for most terminals, except for HAF. HAF may briefly 
scatter out this afternoon, but will mainly remain IFR through the 
TAF period. Moderate onshore flow persists during the day which will 
allow for a more prominent inland push of stratus tonight. The 
marine layer is expected to be around 1000 to 1200 feet overnight 
which will be sufficient enough to reach most terminals. High 
confidence for coastal sites (HAF, MRY, and SNS) to develop IFR to 
LIFR ceilings as early as sunset. Medium confidence on the exact 
arrival of IFR to MVFR ceilings elsewhere, though they may arrive as 
early as 04-06Z Tuesday.

Vicinity of SFO...VFR through the afternoon as westerly winds 
increase to around 15 kt. Borderline MVFR-IFR ceilings are expected 
tonight with the shallow marine layer and persistent onshore push, 
it just becomes a matter of when. High confidence OAK will develop 
ceilings before SFO, though medium confidence on the arrival as they 
may roll in a few hours later than specified.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR to LIFR ceilings will continue to lift 
this morning with VFR conditions to prevail this afternoon. An early 
return of IFR conditions is likely with ceilings gradually lowering 
to LIFR by late this evening/overnight. Some potential for 
reductions in visibility early tomorrow morning but that will depend 
how much the marine layer compresses and if fog is able to develop. 
Breezy onshore winds continue this afternoon/evening before winds 
ease overnight. 

&&

.MARINE...
(Today through Saturday)
Issued at 1126 AM PDT Mon Aug 24 2026

Northwest light to moderate breezes continue into Tuesday and
gradually increase to fresh by the middle of the week. Wind driven
seas remain slight to moderate, though a long period swell is
expected to approach our coastal waters by the end of the week.
Smoke from the Timber Fire continues to impact visibility to as
low  as 2 miles along the Big Sur coast.

&&

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

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Navarrete
MARINE...Navarrete

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Prepared by Boulder-Creek.com Weather at: Mon Aug 24 16:30:03 PDT 2026