Technical NOAA Weather Discussion

FXUS66 KMTR 161154
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
454 AM PDT Sun Aug 16 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1102 PM PDT Sat Aug 15 2026

 - Gradual warming and drying trend into next week

&&

.SHORT TERM...
Issued at 1102 PM PDT Sat Aug 15 2026
(Tonight through Monday)

Heights will begin to rise Sunday as upper-level ridging nudges in 
from the east. We're already seeing an effect of this with a 
compressing marine layer bringing lower clouds and less inland 
extent. Sunday morning will offer another chance for drizzle along 
the coast and in the higher terrain. Temperatures will remain below 
normal under the marine layer influence with inland and higher 
elevation locations warming to near normal. Diurnal winds will keep 
smoke from the Timber Fire out to sea with downsloping (easterly) 
winds in the morning and onshore (northwesterly) winds in the 
afternoon.

&&

.LONG TERM...
Issued at 1102 PM PDT Sat Aug 15 2026
(Monday night through next Saturday)

Global ensemble clusters are in agreement that upper-level ridging 
will nose, and ultimately build, into the Intermountain West through 
Thursday. Sensible weather wise, locations inland from and above the 
compressed marine layer (~1,000 feet) will moderate to near to 
slightly above normal. Along the coast, temperatures will remain 
below normal with evening/morning clouds. To put this event into 
context, 850 mb temperatures will increase to the 75th-90th 
percentile; even so, no records are forecast. Even with the warming 
and drying trend, heat and fire weather impacts are expected to 
remain minor. Fire weather wise, seasonably elevated conditions with 
rapid rates of spread on any wind-and-terrain aligned starts in 
receptive vegetation will be possible in higher terrain, 
specifically with the diurnal sea breeze in the
afternoons/evenings.

&&

.AVIATION...
(12Z TAFS)
Issued at 435 AM PDT Sun Aug 16 2026

IFR to LIFR conditions are being observed across the Bay Area and
Monterey Peninsula thanks to a compressing marine layer. LIFR CIGs
are most likely directly along the coast while confidence is
slightly higher in IFR CIGs across the interior. With the
compressing marine layer there is some potential for fog to
develop along the coast and North Bay Valleys. Models are in good
agreement that conditions will improve by 18-19Z which should be
slightly earlier than yesterday. Breezy afternoon winds weaken
overnight, becoming light and variable. Widespread stratus is
expected again tonight with IFR-LIFR CIGs returning. Moderate
confidence that there will be reductions in visibility along the
coast tonight with some potential for fog.

Vicinity of SFO...IFR CIGs continue through late this morning with
a low (20-30%) chance of LIFR CIGs at least briefly developing
this morning. Stratus is expected to clear by late morning before
returning again this evening. Current thinking is that CIGs will
gradually lower from MVFR to IFR overnight. Breezy onshore winds
expected during the day with light, offshore at times, winds
expected overnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR-LIFR CIGs continue this morning with
some potential for fog to develop through 16/17Z. CIGs clear at
SNS by late morning but confidence is lower that ceilings will
clear at MRY today. Guidance shows stratus lingering along the
coast with MRY just on the edge of it today. Opted for a less
optimistic TAF with stratus persisting at MRY through the day.
Otherwise, stratus returns by the early evening with ceilings
lowering to IFR-LIFR. LIFR CIGs are more likely given the
compressing marine layer.

&&

.MARINE...
(Today through Friday)
Issued at 435 AM PDT Sun Aug 16 2026

A gentle to moderate northwesterly breeze persists into Monday
with localized fresh gusts possible across the interior waters.
Winds increase to fresh to strong late Monday and remain elevated
through the end of the forecast period. Seas of around 4 to 5
feet will build to 7 to 8 feet by mid week. A long period
southerly swell around 15 to 17 seconds will continue to diminish
through the early work week.

&&

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

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Kennedy
MARINE...Kennedy

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Prepared by Boulder-Creek.com Weather at: Sun Aug 16 06:30:02 PDT 2026
From the National Weather Service