FXUS66 KMTR 161744
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1044 AM PDT Sun Aug 16 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 1102 PM PDT Sat Aug 15 2026
- Gradual warming and drying trend into next week
&&
.UPDATE...
Issued at 850 AM PDT Sun Aug 16 2026
Water vapor imagery shows an upper level trough of low pressure
off the California Coast and high pressure over the Desert
Southwest this morning. As a result, California remains situated
between the two, with south southwesterly flow aloft and a
relatively deep marine layer along the coast, although not as deep
as yesterday. In fact, the 12z KOAK sounding shows the atmosphere
saturated between roughly 600 and 1800 feet. This corresponds
well to the ceilings that we are seeing across our observing sites
as well. Given the depth of the marine layer, we have seen some
drizzle as well this morning, with a number of locations reporting
a hundredth or two. The winner for drizzlefest though is Point
Lobos, Mound Meadow, with 0.03 inches.
This deep marine layer will keep the area quite cool today, with
temperatures staying below normal for the majority of the Bay Area
and near normal for our fartherest inland areas and upper
elevations. Current forecast seems to be handling this well, so no
updates are planned at this time. One other note given that the
marine layer was shallower this morning that yesterday, some of
the upper elevations did not have as good of a humidity recovery.
This nocturnal drying trend will likely continue through the
week, as the high pressure tries to expand into the area. Palmer
&&
.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...
(18Z TAFS)
Issued at 1044 AM PDT Sun Aug 16 2026
Stratus, fog, patchy drizzle /MVFR-IFR-LIFR/ are steadily mixing
out and dissipating otherwise it's VFR. Stratus, fog and patchy
drizzle /MVFR-IFR-LIFR/ redevelop tonight and Monday morning.
Vicinity of SFO...Stratus /MVFR/ mixing out to VFR 1930z today.
Stratus /MVFR-IFR/ redevelops tonight and Monday morning. Low
clouds /MVFR/ mixing out to VFR 20z Monday. West to northwest
wind 5 to 15 knots.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Stratus /IFR/ improving to MVFR-VFR in
the afternoon. Stratus /IFR/ redevelops tonight and Monday morning.
West to northwest winds 5 to 15 knots.
&&
.MARINE...
(Today through Friday)
Issued at 850 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...Canepa
MARINE...Canepa
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Prepared by Boulder-Creek.com Weather at: Sun Aug 16 12:30:02 PDT 2026
From the National Weather Service
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