FXUS66 KMTR 031625
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
925 AM PDT Wed Jun 3 2026
...New UPDATE...
.KEY MESSAGES...
Updated at 1145 PM PDT Tue Jun 2 2026
- Relatively weak cold front pushes south through our area today
- Breezy to gusty onshore winds this afternoon and tonight
- Notable cool down for the weekend into the beginning of next
week remains on track
&&
.UPDATE...
Issued at 920 AM PDT Wed Jun 3 2026
Much less stratus this morning than 24 hours ago thanks largely in
part to an approaching cold front and an increasing N-S gradient.
As noted below, made some further refinements on today's max
temperatures away from the coast. Lowered max temps today for
inland valleys 3 to 5 degrees.
Otherwise, the more noteworthy weather impact today will be the
winds. The increasing N-S gradient with onshore flow will lead to
gusty winds over the waters, along the immediate coast, and inland
valleys/passes. Peak winds will be late this afternoon through
early this evening with gusts 30 to 40 mph in the windiest
locations.
MM
&&
.SHORT TERM...
Issued at 1145 PM PDT Tue Jun 2 2026
(Today and tonight)
The effects of a progressive, short wave upper trough beginning to
transect our area to the north overnight are already being felt over
the North Bay with drier air mixing closer to the surface and likely
to hold off a deeper marine layer push into some of the North Bay
valleys for the remainder of the overnight into early Wednesday
morning. Where the marine layer does make inroads tonight, we'll see
clearing a little sooner than what we saw on Tuesday. While clearing
is expected along the coast, the strengthening onshore flow will
maintain influence across coastal areas, so dropped highs a few
degrees from NBM for most of the immediate coast line, and may need
to be lowered further based on trends later this morning. Otherwise
temperatures today will be a few degrees warmer inland than Tuesday,
except for the North Bay where the temps will jump into the 80s to
low 90s.
As the upper trough shifts east later this afternoon, gradient
forcing becomes better aligned for strengthening northwest onshore
flow area wide, with gusty winds developing this afternoon into the
evening hours, especially for higher elevations and channeled
valleys. There's some uncertainty in just how far the marine layer
will progress inland tonight into early Thursday morning. A drier
airmass in the wake of the cold front and easing winds after
midnight may somewhat limit the marine layer's inland progress
despite the marine layer slightly strengthening just offshore.
&&
.LONG TERM...
Issued at 1140 PM PDT Tue Jun 2 2026
(Thursday through Tuesday)
Not much change in the extended forecast with only subtle variations
in daytime highs Thursday and Friday, especially inland. We begin
feeling the influence of the deepening trough along the Pacific
Coastline later in the day on Friday. H85 temps peak in the low
20s(C) Thursday and Friday and are down to around 14C-16C for the
weekend into next week, which will result in surface temperatures
around 5-10 degrees below normal for the weekend into the beginning
of next week. There is a signal for some potential unimpactful light
rain later Monday into Tuesday, there is poor consensus in
deterministic guidance evolves the timing and position of the
trough. However, ensemble guidance provides high confidence in the
overall synoptic troughing persisting beyond the current extended
forecast.
&&
.AVIATION...
(12Z TAFS)
Issued at 449 AM PDT Wed Jun 3 2026
Currently a mixed bag of LIFR-VFR with high clouds streaming in
from the north. A dry cold front will add complexity to the
forecast with the aforementioned high clouds and an increase in
onshore winds that'll result in mixing of the atmosphere. Onshore
winds will increase through the day with gusts of 20-30 knots
expected this afternoon and evening. Relatively lower confidence
in the forecast, especially in the return of stratus tonight.
Guidance/models suggest that it'll be a later arrival than what
has been happening with ceilings likely in the low-end MVFR
range. Highest confidence along the coast with lowest confidence
in the interior.
Vicinity of SFO...Currently IFR with westerly flow. High confidence
in VFR by late-morning in the 16Z-17Z timeframe. Westerly winds will
increase through the day with gusts of 30-35 knots likely this
afternoon and evening. Moderate (45%) confidence in a ceiling
returning to the terminal tonight - it'll likely be low-end MVFR.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Currently LIFR with westerly flow at MRY
and IFR with westerly flow at SNS. Fog is being observed across the
Central Coast so there is the potential for both terminals to
further deteriorate this morning, but confidence is low. Moderate
(60%) confidence on ceilings on the cusp of IFR/MVFR returning to
the terminals tonight.
&&
.MARINE...
(Today through Monday)
Issued at 449 AM PDT Wed Jun 3 2026
Hazardous conditions for small craft are expected at least through
Saturday due to strong northerly breezes. Gale force gusts are
expected for the outer waters and the coastal jet regions.
Moderate seas will prevail today, building to become rough
tomorrow and into the weekend. Conditions will slowly begin to
improve Sunday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT
Thursday for Mry Bay-SF Bay N of Bay Bridge.
Gale Warning until 3 AM PDT Friday for Pt Arena to Pt Reyes 0-10
nm-Pt Arena to Pt Reyes 10-60 NM.
Gale Warning until 3 AM PDT Thursday for Pt Reyes to Pigeon Pt 0-
10 nm.
Small Craft Advisory until 9 AM PDT Thursday for Pigeon Pt to Pt
Pinos 0-10 nm.
Gale Warning until 9 AM PDT Thursday for Pt Pinos to Pt Piedras
Blancas 0-10 nm.
Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...Sarment
MARINE...Sarment
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Prepared by Boulder-Creek.com Weather at: Wed Jun 3 10:30:03 PDT 2026
From the National Weather Service
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