FXUS66 KMTR 021141
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
441 AM PDT Sun Aug 2 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1220 PM PDT Sat Aug 1 2026
- Moderate HeatRisk in the interior through Monday with some
patches lingering through the next week
- Near critical fire weather threat across the interior North and
East Bays, and the Diablo and Santa Lucia ranges through Monday
- Hazardous beach conditions across the Pacific Coast with an
increased risk for sneaker waves and rip currents through the
afternoon
- Strong and gusty winds develop over coastal waters north of Pt
Reyes through Sunday
&&
.SHORT TERM...
Issued at 208 AM PDT Sun Aug 2 2026
(Today and tonight)
An upper level disturbance will pass over the PacNW today, with
quasi-zonal flow to weak troughing setting up over northern CA. To
our southwest west, high pressure is being suppressed over the Desert
Southwest and southern CA. What does that mean for us in the short
term? Well, it means the marine layer will remain compressed as a
result, at about 500ft and hugging the San Mateo and Central Coast
line which means cloudy skies, patchy dense fog, and perhaps coastal
drizzle through the mid morning. Skies will then clear, leading to a
mainly sunny day across the region. Moderate HeatRisk is expected
today for interior locations where temperatures reach the mid 90s to
low 100s. Elsewhere, temperatures rise into the low 70s to mid 80s
unless you're immediately along the coast where temperatures 60s.
&&
.LONG TERM...
Issued at 208 AM PDT Sun Aug 2 2026
(Monday through Saturday)
Little change for Monday as the aforementioned upper level trough
pushes east, allowing the pattern to change from quasi-zonal and
troughy to quasi-zonal with high pressure building in. The forecast
will essentially be on repeat, with perhaps interior temperatures
warming up a few degrees. Heading into midweek, there are a few
items that could affect temperatures. The first being onshore flow
ushering in some cooler air; however, it will be dependent on how
quickly the high builds in. If it is able to build, 850mb temps look
to be fairly warm in the deterministic guidance. This means temps
may need to be bumped up a few degrees inland instead of showing a
subtle cooling trend. Beyond that high pressure looks to build and
hold leading to a warming trend for late week and into the
weekend.
&&
.AVIATION...
(12Z TAFS)
Issued at 429 AM PDT Sun Aug 2 2026
VFR everywhere except the coast where patchy stratus is filling in
over the Monterey Bay and San Mateo coastline. Given the
compressed marine layer, highest confidence in patchy IFR to LIFR
CIGs along the coast with stratus not expected to extend inland.
High pressure will keep the marine layer compressed again tonight
and see a late return of stratus along the coast. Currently not
expecting stratus to extend inland tonight due to the compressed
marine layer. Breezy onshore winds return this afternoon before
winds decrease overnight.
Vicinity of SFO...VFR. The marine layer remains compressed due to
high pressure which will prevent stratus from extending inland.
Guidance shows some potential for patchy stratus to reach SFO
early this morning (12-16Z) but confidence is low that this will
occur. Breezy northwesterly winds expected this afternoon/evening
before winds decrease overnight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...IFR to LIFR conditions expected this
morning. Some potential for patchy fog to impact MRY this morning
with visibilities decreasing to around 1-2SM. Conditions improve
by late morning with VFR through the afternoon. There is mixed
confidence on tonight's stratus return. Ensemble guidance again
suggests a later return is likely at both sites with the HRRR
suggesting both sites could stay VFR through much of tonight. This
scenario cannot be fully written off due to how compressed the
marine layer is and the potential for high pressure to fully mix
out the marine layer. For the 06Z TAFs, leaned on persistence to
have stratus return late tonight but this may need to be amended
in future TAF issuances.
&&
.MARINE...
(Today through Friday)
Issued at 429 AM PDT Sun Aug 2 2026
Strong to near gale force northwesterly winds continue through
Sunday before diminishing late Sunday into early Monday. The
northern coastal waters will have frequent gale force gusts and
occasional storm force gusts through early Monday. Rough to very
rough (9 to 15 foot) wind driven seas continue to build today and
remain elevated through the early work week.
&&
.FIRE WEATHER...
Issued at 452 AM PDT Sat Aug 1 2026
Near critical fire weather conditions are expected through the
weekend and potentially into next week. Temperatures remain around
10 to 15 degrees above normal across the interior through early
next week with highs in the upper 80s to 90s. No major changes to
the forecasted dry conditions. Daytime humidity retention remains
poor across the interior (25-30%) with humidity values dropping
into the 10s across the interior Central Coast, East Bay
Hills/Valleys, and the higher elevations. Portions of the interior
Central Coast may see daytime humidity values drop into the single
digits this weekend into early next week. Overnight RH recovery
remains poor at locations above 2,000 feet with values between 25
to 40% expected with some favored locations struggling to reach
even 25%. This will be particularly true across the Mayacamas,
highest peaks of the East Bay Hills, the Diablo Range, the Santa
Cruz Mountains, the Santa Lucia and Gabilan Ranges. Nocturnal
drying (rapid decrease in RH through the pre- dawn hours) may also
transpire which will increase the burn period or time in which
fire behavior may remain active. Energy Release Components (ERC)
are projected to climb above the 97th percentile across the
interior Central Coast and Mid Coast to Mendocino (North Bay)
zone. ERC values are rapidly climbing across the Diablo-Santa
Cruz zone (Diablo Mountains and Santa Cruz Mountains) with values
approaching the 97th percentile by next week. Diurnally breezy
onshore winds are expected along the coast, mountain gaps and
passes, and along the ridgelines each afternoon/evening. With
near critically dry conditions and above normal temperatures
expected, individuals across these areas are advised to avoid
activities that may spark a fire. Fire crews are urged to exercise
extra caution when executing any prescribed burns, especially
where fuels, topography, and weather align.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
Reyes 0-10 nm.
Small Craft Advisory until 5 AM PDT early this morning for
Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Gale Warning until 3 AM PDT Monday for Pt Arena to Pt Reyes 10-
60 NM.
Small Craft Advisory until 3 PM PDT Monday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...KR
LONG TERM....KR
AVIATION...Kennedy
MARINE...Kennedy
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Prepared by Boulder-Creek.com Weather at: Sun Aug 2 06:30:03 PDT 2026
From the National Weather Service
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