FXUS66 KMTR 262327
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
427 PM PDT Sun Jul 26 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 145 PM PDT Sun Jul 26 2026
- Breezy onshore winds expected each afternoon and evening
through early in the week
- Gradual warming starting midweek, with increasing Moderate
HeatRisk for interior locations heading into the weekend
- Elevated fire weather threat across the Diablo and Santa Lucia
Ranges this week
- Hazardous beach conditions at the Pacific Coast with an
increased risk for sneaker waves and rip currents thru mid-week
&&
.SHORT TERM...
Issued at 145 PM PDT Sun Jul 26 2026
(This evening through Monday night)
Coastal stratus continues to gradually wane and the feed of clouds
across Marin and the greater Bay Area will diminish through mid to
late afternoon. Unlike the past few days, there's more stratus
across the coastal zones and this may signal a better developed
marine layer. 24 hour RH and temperature departures also indicate
a more noteworthy marine influence, especially along the
immediate coastline. However, areas across the interior portions
of the North Bay, East Bay, and Central Coast, temperatures are
2-5 degrees above where they were this time yesterday with RH 5 to
15 percent lower as well. This will serve to elevate the fire
weather threat, this afternoon particularly in some of the wind
corridors, gaps, and passes (e.g., Altamont Pass, southern Salinas
Valley).
While tonight will see a better push of the stratus inland, the
overall depth of the marine layer is expected to remain between
1000-1500 feet. This will mean that some of the higher elevations
stay parched with RH recovery under 50 percent. More specifics
are available in the fire weather section below. Visibility
reductions may also be more of a possibility along the coast as
the marine layer compresses and provides a more favorable
hydrolapse for fog. Locations that are inland, but near bodies of
water (lakes, river, streams), may also stand a greater chance of
mist/fog, resulting in potential hazardous driving conditions for
the Monday morning commute.
Fog, clouds, and stratus should mix out through the day on Monday.
High temperatures on Monday will be 1-2 degrees greater than
today (Sunday), especially if the marine stratus fails to
materialize or dissipates quicker than currently anticipated.
Highs are will range in the mid/upper 60s along the coast to 70s
and 80s across the urban corridors. Portions of the Santa Lucia
and Diablo Ranges stand the greatest chance to exceed temperatures
above 100 degrees. The fire weather threat will remain elevated
during the afternoon with the breezy, dry, and warm conditions
across interior North Bay, East Bay, and the central Coast.
&&
.LONG TERM...
Issued at 145 PM PDT Sun Jul 26 2026
(Tuesday through next Saturday)
A gradual warming trend is anticipated mid-week and into next
weekend. There are indications that heat will be impactful,
especially for interior regions. There are some caveats, however.
Overall the synoptic scale pattern will be such that high pressure
will build in from the Pacific Southwest with broad troughing
across the Pacific Northwest. As ridging builds, we'll see
temperatures slowly tick upward areawide. Taking a look at the
range of possibilities using K-Means clustering as well as
internal model spread tools indicates a couple of very plausible
scenarios with regard to the position of the aforementioned
synoptic scale features. The placement of these features will
dictate just how hot areas get (or how cool they stay).
For the first scenario, just over half of the 100 member multi-
model ensemble suggest that a couple of reinforcing upper troughs
will swing through the Pacific Northwest through the middle to end
of next week. This scenario would slow or limit the expansion of
the ridge westward and would keep our region more influenced by
the marine environment and cooler. This would translate to more in
the way of "Minor" to low-end "Moderate" Heatrisk. While still
impactful, this would relegate heat impacts to extremely sensitive
individuals such as the very young, elderly, and those with
little to no access to adequate cooling or hydration.
Alternatively, the second scenario, just under half of the multi-
model ensemble, suggest more diffuse upper troughs across the
Pacific Northwest, with the Pacific Southwest ridge expanding
farther west. A farther west ridge would be more efficient at
suppressing the marine layer and in fact, some deterministic NWP
does imply offshore flow (largely across the Central Coast) which
would support higher end MaxT temperatures late this upcoming week
and into next weekend. Subsequently, more widespread "Moderate"
with even a potential for pockets of "Major" Heatrisks would be
more probable in this scenario. This level of heat has the
potential to impact even those that are not necessarily sensitive
to the heat.
So what's the actual forecast? The current forecast leans more on
the higher scenario as it's in lockstep with the larger global
model guidance that has been highlighting the potential for
impactful heat for the last 1-2 weeks. In addition, 850mb
temperatures (which typically prove to be useful for MaxT
forecasting) are approaching the 90th percentile for late July and
into early August. With these factors in mind, MaxT were adjusted
leaning more toward the higher end (but not going all end) of the
guidance envelope. While the details of exactly how hot it will
get are to be ironed out over the next several days, it's
important to stress that individuals will still need to practice
their heat safety protocols, especially those not near the coast.
These protocols include hydrate with plenty of water, taking
frequent breaks in the shade or A/C (where applicable) and
shifting outdoor activities to the cooler time of day. Also, never
leave kids or pets in vehicles unattended.
In addition, if headed to the beach, please be sure to check
conditions and NEVER turn your back on the ocean as there will be
an increased threat for sneaker waves and rip currents. There have
been reports of weather rescues at some popular beaches and the
potential will increase as more individuals head to the beach with
the warmer stretch of weather anticipated.
&&
.AVIATION...
(00Z TAFS)
Issued at 416 PM PDT Sun Jul 26 2026
Currently VFR (MVFR at HAF) with stratus off the coast. Very
little change in the pattern will yield a persistence forecast
with IFR/low-end MVFR ceilings returning to most terminals tonight.
With stratus over the water and slow to clear this morning,
terminals will likely be impacted earlier than they were last
night. Widespread VFR is expected by tomorrow afternoon. Diurnal
winds will prevail.
Vicinity of SFO...Currently VFR with gusty westerly flow. Strong
westerly winds with gusts up to 30 knots are expected through this
evening. Moderate confidence on a low-end MVFR ceiling returning
tonight with VFR prevailing by tomorrow afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Currently VFR with westerly flow at both
terminals. High (80%) confidence on IFR ceilings returning
tonight with VFR prevailing by tomorrow afternoon.
&&
.MARINE...
(Tonight through next Friday)
Issued at 416 PM PDT Sun Jul 26 2026
Northwest breezes remain fresh, continuing on a trend to increase
to strong by Tuesday. Frequent gale force gusts are forecast
along the Big Sur coastline. Moderate seas also continue to build
to rough by Wednesday. Impacts from a long period southerly swell
due to distant tropical cyclone activity in the East Pacific
prevails into the week.
&&
.FIRE WEATHER...
Issued at 145 PM PDT Sun Jul 26 2026
Increased breezes, while onshore, when combined with critically
dry afternoon RH through the week will translate to an elevated
fire weather threat. This threat will persist through mid-week and
potentially into the latter half of the week and into the
weekend. The most likely region for starts and fire spread will be
across the interior Central Coast where Energy Release Components
(ERC) are projected to climb above the 95th percentile. While
morning RH recovery will moderate some through the week, the
shallow marine layer will equate to generally poor overnight
recovery for elevations at or above 2,000 feet through Wednesday
morning. This will be particularly true across the Mayacamas,
highest peaks of the East Bay Hills, the Diablo Range, Santa Cruz
Mountains, Santa Lucia and Gabilan Ranges. Nocturnal drying (rapid
decrease in RH through the pre-danw hours) may also transpire
which will increase the burn period or time in which fire behavior
may not diminish. 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 145 PM PDT Sun Jul 26 2026
Tropical cyclones in the Eastern Pacific will continue to
generate 18-20 second (long-period) southwesterly swell which has
reached the coastline of the San Francisco Bay Area and Central
Coast. As such, sneaker waves and strong rip currents are the
primary concerns. However, breaking waves can reach up to 10 feet
along some south and southwest facing beaches and break points
(like 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 and can result in people and
pets being swept into the cold, turbulent ocean. Rip currents are
strong enough to pull the strongest swimmers away from shore.
Check conditions before you head out! Swim near a lifeguard if
possible. Stay back from the beach, and 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. Hazardous beach conditions
are anticipated to persist through Wednesday afternoon.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Wednesday afternoon for CAZ006-
505-509-529-530.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF
Bay N of Bay Bridge.
Small Craft Advisory from 9 AM to 9 PM PDT Monday for Mry Bay-SF
Bay N of Bay Bridge.
Small Craft Advisory until 9 PM PDT Monday for Pigeon Pt to Pt
Pinos 0-10 nm-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 Reyes to
Pigeon Pt 0-10 nm.
Gale Warning until 9 PM PDT Monday for Pt Pinos to Pt Piedras
Blancas 0-10 nm.
&&
$$
SHORT TERM...Bain
LONG TERM....Bain
AVIATION...Sarment
MARINE...Navarrete
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Prepared by Boulder-Creek.com Weather at: Sun Jul 26 16:30:04 PDT 2026
From the National Weather Service
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