FXUS66 KMTR 191734
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1034 AM PDT Wed Aug 19 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1201 AM PDT Wed Aug 19 2026

 - Compressed marine layer today, increases Thursday into the 
   weekend

 - Near normal temperatures today followed by a gradual cooling
   into the weekend

 - Elevations above about 1000 feet will have warm temperatures
   and RH values in the teens this morning into the afternoon

&&

.UPDATE...
Issued at 944 AM PDT Wed Aug 19 2026

The forecast looks to be on track this morning as the marine layer
slowly pulls back to the coast. If the trend continues we should 
see high temperatures similar to yesterday. Interior valley temps
will range from the 80s to low 90s for the majority of the region,
though the upper 90s to near 100 are expected for the southern 
Salinas Valley and around Fort Hunter Liggett. The higher
elevations for the interior mountains will be warmer as well, with
temps generally in the upper 80s to near 100. And for those in
along the coast and near the Bay, temps will range from the 60s to
low 80s. 

&&

.SHORT TERM...
Issued at 1201 AM PDT Wed Aug 19 2026
(Today and tonight)

A slightly more shallow marine layer tonight resulted in a somewhat 
later onset of stratus pushing inland with less extensive coverage 
than what was seen last night into early Tuesday morning. Another 
mild overnight into early this morning should result in stratus 
retreating back to the coast an hour or two sooner than we generally 
see this time of year. Todays warmup will barely be noticeable for 
areas below 1000ft away from the coast, with temperatures at higher 
elevations across the East Bay Hills and Santa Lucias including Big 
Sur and the Timber fire, running 10 degrees or more above normal. 
MinRH values will be in the teens this afternoon across those 
elevated locations, fortunately light winds continue to be a 
mitigating factor. The weak fetch of offshore flow above the marine 
layer over the southern Central Coast will shift late tonight with 
improved RH recovery expected into early Thursday, along with an 
increase in the marine layer depth.

&&

.LONG TERM...
Issued at 1201 AM PDT Wed Aug 19 2026
(Thursday through Tuesday)

Troughing persists through the extended forecast with gradually 
cooling setting in on Thursday and continuing through the weekend 
into next week. The persistent ridging to our east increases to near 
600dm by the middle of next week, while continuing steer at least a 
couple of tropical waves around its perimeter well to our south. The 
potential tropical system still depicted beyond the official 
forecast period still appears to offer little impact for our area 
while we will continue to monitor any mid-level moisture advection.

&&

.AVIATION...
(18Z TAFS)
Issued at 1027 AM PDT Wed Aug 19 2026

A mix of IFR/MVFR conditions this morning with high confidence of
stratus to retreat to the coastline late this morning and more so
by this afternoon. This will give way to VFR conditions this 
afternoon across inland TAF sites. Increasing onshore flow will 
persist throughout the afternoon and early evening hours before 
diminishing late evening. Stratus and reduced visibilities return 
first around the Monterey Bay terminals and then across the Bay 
Area terminals late in the night and into Thursday morning. 

Vicinity of SFO...VFR. Onshore winds increase this afternoon with
gusts up to 25 kt through the early evening. Low to moderate 
confidence in the return of stratus tonight with some models 
suggesting the low cloud cover will remain confined over OAK. 
However, opted for IFR/MVFR ceilings over the terminal due to 
persistence and LAMP guidance. However, this will need to be 
monitored closely throughout the night. Onshore winds increase 
Thursday afternoon with similar clearing time as today if not a 
bit earlier.

SFO Bridge Approach...Low to moderate confidence for MVFR 
ceilings to return early Thursday morning. Otherwise, similar to
SFO. 

Monterey Bay Terminals...IFR, giving way to VFR by late morning 
into early afternoon. Onshore winds increase this afternoon with 
moderate to high confidence of IFR conditions returning late this 
evening and lowering to LIFR late in the night. 

&&

.MARINE...
(Today through Monday)
Issued at 944 AM PDT Wed Aug 19 2026

Locally strong northwesterly breezes across the northern outer
waters and along the coastal jet regions will bring hazardous
conditions for small craft periodically through the weekend.
Breezy fresh winds are expected across the San Pablo Bay and the
San Francisco Bay with locally stronger gusts possible where
terrain promotes wind funneling. Rough seas in the outer waters
will subside Thursday with moderate seas prevailing by Friday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT 
     Thursday for Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 3 PM PDT 
     Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...RGass
MARINE...RGass

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Prepared by Boulder-Creek.com Weather at: Wed Aug 19 12:30:03 PDT 2026