FXUS66 KMTR 310449
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
949 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

&&

.UPDATE...
Issued at 831 PM PDT Thu Jul 30 2026

First and foremost, let's discuss the weather impacting the 
Woodside Fire on the Sonoma Coast. Weather wise, wind continues to
be the main driver of fire activity as temps are mild and 
humidity is moderate. Winds this afternoon and this evening have 
been very gusty and out of the northwest with peak wind gusts in 
the 25-35 mph range. For the rest of the night winds will ease
slightly, but still be rather breezy out of the northwest.
Satellite imagery and stronger transport winds have definitely 
shown widespread smoke coverage downstream of the fire in Petaluma
and Sonoma Valleys. As we see some cooling overnight expect the
smoke to settle into the valleys. For air quality impacts please
consult the Bay Area Air Quality Mng District. at baaqmd.gov

Quick update to the forecast was done this evening to include
smoke overnight and early tomorrow.

MM

&&

.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...
(06Z TAFS)
Issued at 948 PM PDT Thu Jul 30 2026

Satellite this evening shows a few blips of stratus in San Mateo and 
Monterey counties, otherwise clear skies exist elsewhere. Smoke from 
the Woodside Fire has billowed south and eastward, which has brought 
reduced cig and vis to KSTS this evening. The HRRR smoke model 
indicates there may be less smoke produced overnight, but given that 
it has already sunk into the valleys of the North Bay, we could 
continue to see periods of MVFR to IFR visibility and ceiling when 
winds ease. Otherwise, when sites are not being influenced by 
wildfire smoke, look VFR conditions are expected to prevail tonight 
and into tomorrow. The marine layer is expected to be around 500-
800ft which will keep stratus development limited. The areas that 
have the best chance for stratus tonight are around Monterey Bay and 
Half Moon Bay. Some models hint at it building back into the Napa 
Valley 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...Onshore winds continue to gradually decrease this 
evening, 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. Opted to IFR cigs tonight, and hinted at LIFR cigs 
with FEW004. If we get LIFR cigs they'd likely occur around or 
shortly after sunrise. Skies clear by mid morning, with VFR 
conditions prevailing afterwards. Models show stratus attempting to 
come in around the end of the TAF cycle, but confidence was too low 
to add anything other than FEW007. Medium to high confidence in the 
forecast. 

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 948 PM PDT Thu Jul 30 2026

Fresh northwest breezes become strong across our coastal waters
by Saturday with moderate seas building to rough in response.
Conditions will become dangerous, late Saturday and into Sunday,
especially across the northern waters. Northerly winds continue
to increase on Sunday with severe gale to storm force gusts north
of Point Reyes and gale force gusts from Point Reyes to Pigeon
Point. Seas will to become very rough. Winds gradually decrease
for the early portion of next week, which will allow very rough
seas to 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 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...KR

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Prepared by Boulder-Creek.com Weather at: Fri Jul 31 00:30:02 PDT 2026