325
FXUS66 KMTR 030031
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
531 PM PDT Mon Jun 2 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 102 PM PDT Mon Jun 2 2025

Generally quiescent conditions are anticipated through the entire
outlook period. Temperatures will initially be near or just below
normal, before conditions moderate through the end of the week
and into the weekend. Daily onshore breezes are forecast, with
portions of the west Delta, within gaps and channels, and across
higher terrain potentially experiencing gusts over 30 mph.

&&

.SHORT TERM...
Issued at 102 PM PDT Mon Jun 2 2025
(This evening through Tuesday)

Short Term Key Messages
-Just below or near normal temperatures
-Increased breezes across the west Delta/areas of complex terrain
-Non-Zero risk for elevated convection

Water vapor imagery early this afternoon indicates an upper low
churning southward toward the California Bight. It`ll get
enveloped within the main flow southern stream flow over the next
48 hours. Current water vapor imagery across the East Pac does
indicate remnant moisture around the flat H5 ridge will be drawn
northward. Current indications are that that flow around the west
side of the high and east side/ahead of upper low will be such
that a majority of the richer plume will remain south of our area.
Still, some guidance, most notably the NAM (which typically has a
slight wet bias), indicates that precipitable water (PWAT) just
over 3/4 of an inch may eek into southern Monterey and San Benito
counties late tonight into the pre-dawn hours on Tuesday. For now,
the main trigger would need to be orographic ascent across the
Gabilan Range. For now, I`ll advertise a 5 PoP across this region
as confidence isn`t high (and not bolstered by any NCEP or PG&E
high- res NWP), but we`ll keep monitor of this potential,
particularly with 700-500mb lapse rates forecast to approach or
exceed 7 C/km (and they are already around 8 C/km per our 12 UTC
OAK RAOB). Otherwise, pockets of drizzle/mist cannot be
discounted, particularly along coastal regions.

Otherwise, I expect that we`ll see an uptick in breezes as the
SFO-SAC gradient inches toward 3-4mb. This should fuel a bit more
onshore flow and I anticipate that through some of the
gaps/passes, wind gusts will be enhanced. In fact, the probability
of peak wind gusts of greater than 25-30 mph exceeds 70% for
portions of the North Bay Mountains, west Delta and East Bay Hills
with around a 20-30%% chance that peak winds could gust over 40
mph on Tuesday.

Otherwise, the onshore flow (which isn`t unusual for this time of
year) will support near to just below normal temperatures during
the short term forecast period.

&&

.LONG TERM...
Issued at 102 PM PDT Mon Jun 2 2025
(Tuesday night through next Sunday)

Long Term Key Messages
-Gradual Warming Trend

With the aforementioned upper low kicking eastward, the overall
long term pattern appears that it`ll be dominated by slight
longwave ridging across the western CONUS. This will translate to
largely uneventful weather (warm and precipitation-free) across
the Bay Area and Central Coast. We`ll likely see a diurnal pattern
characterized by a push of marine stratus onshore during the
overnight hours, with erosion of the marine layer late morning and
into the early afternoon hours.

Toward days 5 through 7, model solutions do begin to show some
variability. Most solutions show a strengthening ridge across the
Pacific Northwest with some model solutions indicating the heart
of this feature will be more centered across Big Sky Country.
There is a solution cluster (mostly comprised of Canadian/GFS
ensemble members) that would support more in the way of troughing
across the PacNW, but this doesn`t really result in a significant
change in the forecast across California. For now, the deterministic
NBM offers a valid solution for above normal warmth continuing
this weekend and onward. This pairs well with extended temperature
outlooks.

&&

.AVIATION...
(00Z TAFS)
Issued at 531 PM PDT Mon Jun 2 2025

Stratus continues to mix out within a weak surface low pressure
area located over the offshore and coastal waters, while over
land it`s clear /VFR/. Coastal stratus and fog redevelop and move
inland on mainly onshore winds tonight and Tuesday morning. The
marine layer will compress overnight, ceilings likely MVFR to
start then lowering to IFR tonight and Tuesday morning. A few
patches of valley fog /LIFR-IFR/ may develop late tonight and
Tuesday morning.

Vicinity of SFO...VFR continuing through the evening and west
wind gusty to 25 knots possibly with a few additional gusts to 30
knots. Stratus /IFR/ develops by 12z Tuesday, mixing out to VFR
17z Tuesday. West wind decreasing mid to late evening, lowering to
light and variable to light northeast wind Tuesday morning.
Northwest to west wind redeveloping Tuesday, gusty to 25 knots
Tuesday afternoon and early evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR continuing through early to mid
evening, then increasing probability of stratus /MVFR-IFR/
developing tonight and Tuesday morning. Stratus mixing out by
late Tuesday morning. West to northwest winds 5 to 15 knots
except locally light and variable tonight and Tuesday morning.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 513 PM PDT Mon Jun 2 2025

Moderate to breezy winds continue to affect the waters, but will
reduce into the evening. Rough seas and significant wave heights
of up to 20 ft continue across the northern outer waters and up to
15 ft across the southern outer waters through early Monday
afternoon. Winds gradually ease by Tuesday but seas will remain
rough with elevated significant wave heights between 10 to 16 ft
continuing late Monday through mid to late week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT Wednesday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Bain
LONG TERM....Bain
AVIATION...Canepa
MARINE...Murdock

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