643
FXUS66 KMTR 021801
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1101 AM PDT Sat Aug 2 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 855 AM PDT Sat Aug 2 2025

 - Deja Vu today, slightly below normal temperatures and generally
   quiet weather.

 - Gusty NW winds Sunday and Monday. Gusts to 40 mph each
   afternoon along isolated coastal locations, as well as favored
   mountain gaps, passes, and valleys.

 - Quiet conditions are restored Tuesday with a subtle warming
   trend into the latter half of the week.

&&

.UPDATE...
Issued at 855 AM PDT Sat Aug 2 2025

Outside of modifications to the late evening/overnight
winds grids, the short term forecast is on track.

Morning stratus continues to slowly erode across the Bay Area and
Central Coast. 24 hour comparisons of the satellite presentation
revealed generally less cloud cover this morning, with the
exception being across portions of the SF Peninsula. This will
translate to MaxTs being a few degrees higher than what was
observed yesterday, especially across the interior. Still,
widespread impactful heat is not anticipated, though never leave
children or pets unattended in a vehicle. Very subtle shortwave
ridging tonight overhead may result in a slight compression of the
marine layer which may translate to more in the way of reduced
visibility, especially at the coast. We`ll dig into this a little
more with the afternoon forecast update.

The real update to the forecast revolved around adjustments to the
wind gusts upward across the East Bay Hills. Cross sections from
the PG&E WRF do advertise favorable thermodynamic and kinematic
profiles needed for enhanced wind gusts. With winds overachieving
a little this morning, the bias corrected short term model
consensus being more representative, it`s reasonable that we`ll
see another round of elevated winds tonight into Sunday morning
(and likely again Sunday night into Monday morning). Winds could
gusts as great as 40 to 50 mph, especially across the Altamont
Pass with weaker, though still enhanced flows, across other gaps,
channels, and passes with a northwest-southeast orientation.

&&

.SHORT TERM...
Issued at 308 AM PDT Sat Aug 2 2025
(Today and tonight)

Another morning with a well-formed marine layer, though a bit
shallower thanks to weak high pressure aloft. Really not much
change to talk about on this fine Saturday, so we`ll save the
talking for the long term discussion, in which we discuss the
upcoming wind event to kick off the week (if the week starts
Sunday for you).

&&

.LONG TERM...
Issued at 308 AM PDT Sat Aug 2 2025
(Sunday through Friday)

The most notable thing to talk about weather-wise in a while (sans
tsunamis...not really "weather" anyway) is the wind event that is
anticipated beginning Sunday afternoon and lasting into Monday
evening. Guidance has been consistent and appears to have a pretty
good hold on things now. A weak, open trough is progged to clip us
to the north which brings a weak jet overhead by midday Sunday.
This pattern supports persistent high surface pressure over the
waters and falling pressure across the Great Basin. Not super
important for impacts, but an interesting tidbit nonetheless; the
position of the jet is conducive gusty winds across our region,
but not exactly in the same way as a typical winter storm that
features a strong jet streak. In this case, the location of the
upper level jet promote low pressure downstream of the jet max.
The main driver of our winds will be this surface pressure
gradient. A byproduct of the jet energy, and not the jet energy
itself. This is in contrast to a strong winter storm where there
is a strong jet aloft and little-to-no stable marine layer, so the
jet energy is able to mix down towards the surface more readily.
Okay what I`m trying to say is that this wind event Sunday and
Monday will most likely be considered "just a normal breezy day"
by many folks. However, for mariners or those traveling, working,
or recreating along the coast or favored passes and valleys
(i.e., San Bruno Gap, Altamont Pass, Salinas Valley), it will be
notably more windy. These areas are likely to see gusts to 35-40
mph during the afternoons Sunday and Monday. Beyond the windy
period, calm conditions return with a slight warming trend that
kicks off into the second half of the week. Forecast target for
temps by the end of next week looks to be about 3-5 degrees above
normal across inland areas, and near normal for coastal areas.

&&

.AVIATION...
(18Z TAFS)
Issued at 1101 AM PDT Sat Aug 2 2025

Stratus and fog /MVFR-IFR/ are steadily mixing out to the coastline,
inland it`s VFR. The marine layer depth varies from approx 900 to
1800 feet. Conditions improving to MVFR-VFR nearer the coast during
the day. For tonight and Sunday morning stratus and fog /MVFR-IFR/
moving back inland.

Vicinity of SFO...Stratus steadily cleared earlier, VFR is forecast
through late morning and the afternoon. Stratus /MVFR/ returns
tonight by 06z and is forecast to continue until 17z-18z Sunday.
Gusty west wind to 20 to 25 knots today and up to 25 to 30 kt
Sunday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus mixing out through late morning
and afternoon. MVFR-VFR during the afternoon, then stratus /MVFR-
IFR/ returns tonight and Sunday morning. Onshore winds 5 to 15
knots.

&&

.MARINE...
(Today through Thursday)
Issued at 1039 AM PDT Sat Aug 2 2025

Widespread fresh to strong northwesterly breezes with near-gale
force gusts will prevail. The coastal jet regions of Point Reyes
and Point Sur can expect isolated gale force gusts. The bays will
have hazardous conditions for small craft during the afternoon and
evening hours, especially Sunday and Monday. Seas will remain
moderate to rough through Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM Sunday to 3 AM PDT Monday for SF
     Bay N of Bay Bridge.

     Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Mry Bay.

     Small Craft Advisory from 9 AM Sunday to 3 AM PDT Monday for Mry
     Bay-Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt
     Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt
     Pinos 0-10 nm.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Canepa
MARINE...Canepa

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