337
FXUS66 KMTR 310055
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
555 PM PDT Thu Jul 30 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1216 PM PDT Thu Jul 30 2026

 - Gradual warming trend through Saturday with Moderate HeatRisk
   in the interior through the early part of next week

 - Elevated fire weather threat across the interior North and East
   Bays, and the Diablo and Santa Lucia ranges through the early
   part of next week

 - Hazardous beach conditions across the Pacific Coast with an
   increased risk for sneaker waves and rip currents through the
   weekend

&&

.SHORT TERM...
Issued at 1216 PM PDT Thu Jul 30 2026
(This evening through Friday night)

Generally clear skies prevail over the region with limited patches
of stratus lingering over the western side of San Francisco, along
the coast of the San Mateo Peninsula down to Pillar Point, and at
the immediate coast of the Monterey Bay region. Today will be the
first day of a warming trend that will dominate the weather pattern
for the next few days and bring temperatures above seasonal averages
to the inland regions, driven by a building high pressure system
expanding into California from the Desert Southwest. High
temperatures will range from the middle 80s to middle 90s across the
inland valleys, up to around 102 within the warmest spots of
southern Monterey and San Benito Counties, the lower 70s to lower
80s along the Bays, and the lower to middle 60s along the Pacific
coast. An onshore push will develop this afternoon and evening,
bringing gusts of 25 to 35 mph along the coast, through gaps and
passes, and within the Salinas Valley.

Tonight, expect the building high pressure system to compress the
marine layer, limiting any stratus and fog impacts to the immediate
coastal regions. Low temperatures on Friday morning range from the
middle to upper 50s in the valleys, to the 60s and lower 70s within
the thermal belts. Highs on Friday will continue to warm with
temperatures around a couple degrees warmer than today`s across most
of the region, save the immediate coast where the compressed marine
layer keeps the region cooler.

Patches of Moderate HeatRisk develop in the interior on Friday,
followed by more widespread Moderate HeatRisk in the interior
Saturday through the early part of next week. This corresponds to a
moderate risk for heat related illnesses for sensitive populations,
including children, the elderly, pregnant women, people with certain
medical conditions, and people who work or live outdoors without
adequate shelter or hydration. Follow these tips to avoid heat-
related illnesses:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

.LONG TERM...
Issued at 1216 PM PDT Thu Jul 30 2026
(Saturday through next Wednesday)

Saturday looks to be the warmest day of this strand of warming with
triple digit highs possible in the far interior regions of northern
Sonoma, northeastern Napa, and eastern Contra Costa counties, while
southern Monterey County sees highs reaching 105 with some isolated
and heavily favored locations making a run for 110. Elsewhere the
inland valleys remain in the 90s while downtown San Francisco and
Oakland hover in the middle 70s to lower 80s. On Sunday, a trough
passing by the Pacific Northwest will interrupt the building ridge
and cause temperatures to plateau, but large scale ridging returns
the next day and could continue into the middle of the next week.

Regarding potential strong winds across the coastal waters this
weekend, the ECMWF EFI backed down a little bit from what the
previous forecaster was seeing last night, but are still showing
high EFI values with a strong shift of tails. Or in layman`s terms,
there`s a strong signal for strong winds and a relatively high
probability for remarkably strong winds, a "boom" situation, if you
will. The PG&E WRF model continues to show a swath of storm force
gusts over 60 mph across the northern waters off the coast of Sonoma
and Marin counties, but it`s almost alone in depicting this, with
the deterministic GFS and the experimental RRFS showing isolated
storm force gusts in the area while the NAM12 and deterministic
ECMWF keep wind gusts at gale force. Will be interesting how the
other high resolution models, namely the higher-resolution NAM and
the HRRR, depict the wind gusts in this are where the time comes.
For now, there wasn`t enough confidence to bump up the wind gusts
for the weekend.

In addition, the upper level pattern could bring us a couple of
offshore bursts over the region, with a notable pulse Sunday night
into Monday particularly across the North Bay and SF Bay regions. As
noted by the previous forecaster, the fire weather concerns
regarding nocturnal drying and downslope warming are obvious, but
that downslope warming could also cause coastal temperatures to be
much warmer than the forecast if it extends through Monday.

As a final note, beach hazards and fire weather concerns continue
into the weekend. See the BEACHES and FIRE WEATHER sections for more
details. One less spark, one less fire, and never turn your back to
the ocean!

&&

.AVIATION...
(00Z TAFS)
Issued at 554 PM PDT Thu Jul 30 2026


Mainly clear skies are being observed across much of the Bay Area
and Central Coast, with the exception being smoke drifting south and
eastward from the Woodside Fire in Sonoma County. VFR conditions are
expected to prevail tonight and into tomorrow for the majority of
the region, as the marine layer compresses to about 500-800ft and
high pressure builds in. Areas that have the best chance for stratus
development tonight are around the Monterey Bay and perhaps around
Half Moon Bay. Some models hint at it building back into the Napa
region and around Oakland, but confidence is low and opted to
continue the hint of stratus at these sites. Medium to high
confidence in the forecast.

Vicinity of SFO...Breezy onshore winds with gusts to 25-28kt will
gradually decrease this evening, with winds gradually falling to
less than 10kt overnight. The tougher question is in regard to the
stratus forecast. As mentioned above, the marine layer is expected
to be around 500-800ft with the KOAK sounding showing a fairly dry
profile. Current thinking is KFSO will likely stay VFR through the
period and if any low clouds try to form it`d likely be between 10-
14Z. Outside of that look for breezy onshore winds to return Friday
afternoon and evening, sustained speeds will be around 15kt with
gusts up to 20-23kt possible. Medium to high confidence in the
forecast.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...The most likely area to see stratus late
tonight and into Friday morning is the Monterey Bay and northern
Salinas Valley. The question for here though, is how will the
compressed marine layer factor things? Will we get another night of
LIFR cigs and perhaps even pockets of fog or will be bottom out with
IFR cigs. Opted to keep the optimistic forecast for IFR cigs
tonight, but with no major changes in the general pattern, LIFR cigs
are possible again around or shortly after sunrise. Skies clear by
mid morning, with VFR conditions prevailing afterwards. Medium to
high confidence in the forecast. &&

.MARINE...
(Tonight through next Wednesday)
Issued at 554 PM PDT Thu Jul 30 2026

Fresh northwest breezes increase to strong across our coastal
waters  by Saturday as moderate seas build to rough. Gale force
winds in the  northern waters increase by Sunday, thereby allowing
seas to become  very rough. Very rough seas subside to moderate by
Wednesday. A long  period southerly swell continues to impact our
coastal waters from  distant tropical activity.

&&

.FIRE WEATHER...
Issued at 1216 PM PDT Thu Jul 30 2026

The overall fire weather picture remains similar to the previous
discussion, with elevated fire weather threats persisting at the
higher elevations through the weekend and possibly beyond.
Overnight RH recovery remains moderate to poor at locations at or
above 2,000 feet with values between 35 to 45 percent, with some
favored locations struggling to even reach 25 percent. 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. Afternoon RH remains critically dry with values between
15 and 30 percent, with far southern portions of the interior
Central Coast potentially seeing min RH near 10 percent. Energy
Release Components (ERC) are projected to climb above the 97th
percentile across the interior Central Coast. Individuals across
the area 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.

&&

.BEACHES...
Issued at 1216 PM PDT Thu Jul 30 2026

Long period southerly to southwesterly swell of 14-17 seconds
continues to impact our coastline through at least Saturday
afternoon, bringing hazardous beach conditions to the Central
Coast and the San Francisco Bay Area. Sneaker waves and strong rip
currents will be the primary threats, with breaking waves up to
10 feet along some south and southwest facing beaches and break
points, such as Santa Cruz, Pacifica, and parts of Stinson or
Ocean Beach. This can be particularly surprising when wave heights
increase suddenly after a period of seemingly tranquil wave
action. In fact, sneaker waves can have 20+ minutes in between the
larger sets (breaking waves) with significant "flat/calm looking"
times between them. Due to the long period, sneaker waves are
powerful and can catch beachgoers by surprise, resulting in people
and pets being swept into the cold, turbulent ocean. Rip currents
are strong enough to pull even the strongest swimmers away from
shore. Check marine conditions before you head out! Swim near a
lifeguard, if possible. Maintain a safe distance from the water,
and stay away from jetties, piers, beachside rocks, and other
waterside infrastructure. Never turn your back to the ocean and if
you have small children or pets at the beach, please keep an eye
on them.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Saturday afternoon for CAZ006-
     505-509-529-530.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-Pt
     Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

     Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Gale Warning from 9 AM to 3 PM PDT Saturday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Friday to 3 PM PDT Saturday for
     Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 PM PDT Friday for Pigeon Pt to Pt
     Pinos 0-10 nm.

     Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Pigeon
     Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 PM PDT Saturday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...KR
MARINE...Navarrete

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