FXUS66 KMTR 011921
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1221 PM PDT Sat Aug 1 2026
...New SHORT TERM, LONG TERM...
.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 1220 PM PDT Sat Aug 1 2026
(This evening through Sunday night)
The satellite picture reveals more extensive stratus coverage
offshore compared to yesterday at this time, and patches of cloud
persist across the coast of the Marin Headlands and the Monterey Bay
region, where an eddy over the bay is keeping the stratus in place
for a little while longer. The marine layer remains relatively
compressed and stratus coverage will be rather limited tonight owing
to a couple factors including an approaching weak cold front and
possible bursts of offshore wind.
The weather pattern continues to be dominated by the high pressure
system centered over the Desert Southwest and extending over the
state, which is leading to widespread temperatures above the
seasonal averages today. Highs today range from the upper 80s to
middle 90s in the inland valleys today, with warm spots in the far
interior North Bay, the eastern part of Contra Costa County, and
southern Monterey and San Benito Counties seeing highs reaching the
triple digits (up to 107 in southern Monterey County). Elsewhere,
highs along the bays range from the middle 70s to the middle 80s,
while the Pacific coast hovers in the middle 60s to lower 70s. On
Sunday, morning lows range from the middle 50s to lower 60s in the
lower elevations, to the middle 60s to the lower 70s in the higher
elevations, and expect highs to be broadly similar to today's,
possibly a couple degrees warmer in some spots.
A weak cold front currently off the coast of California, and
associated with an upper level trough over the Pacific Northwest
and British Columbia, will help tighten the north- south pressure
gradient as it comes into the northern Bay Area and the adjacent
waters before dissipating, with the latest model projections
putting tonight's peak SFO-ACV gradient in the -7 to -8 mb range.
A gradient this strong will help mix out the stratus and promote
stronger winds in the coastal waters, with gale force gusts
widespread and isolated storm force gusts possible. Fortunately
these strong winds remain generally parallel to the coast, but a
weak offshore push is possible tonight across the North Bay and
Central Coast, which could cause warmer and drier conditions to
extend all the way to the coast. Another stronger pulse of
offshore wind is possible Sunday night into Monday morning. Not
strong enough for a Wind Advisory, but strong enough to raise the
fire weather concerns.
Widespread Moderate HeatRisk persists across the interior regions
into Monday with patches of Moderate HeatRisk persisting into the
rest of the 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. Some patches of Major HeatRisk, corresponding to a more
widespread risk for heat-related illnesses, are also expected in the
warmest parts of the interior Central Coast. 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.
As a final note, beach hazards and fire weather concerns continue.
See the BEACHES and FIRE WEATHER sections for more details. One less
spark, one less fire, and never turn your back to the ocean!
&&
.LONG TERM...
Issued at 1220 PM PDT Sat Aug 1 2026
(Monday through next Friday)
The heat continues into Monday as the trough passes by far to the
north across the northern Rockies and western and central Canada,
leaving the ridging pattern generally intact through the early part
of next week. Subtle cooling is possible in the wake of this trough
passage Tuesday and Wednesday, with coverage of the Moderate
HeatRisk becoming patcher in the inland SF Bay Area on those days.
Breezy onshore winds are expected each afternoon and evening, and
the longer range guidance shows temperatures rebounding for the
latter part of the week as the ridge rebuilds over the region.
&&
.AVIATION...
(18Z TAFS)
Issued at 1155 AM PDT Sat Aug 1 2026
Stratus is making its way out of the remaining terminals, giving way
for widespread VFR conditions to prevail through the day. Onshore
winds increase through the afternoon and ease shortly after sunset.
The marine layer remains compressed to around 1000 feet this TAF
period, therefore low confidence on how expansive it will become
overnight. High confidence for SJC and LVK to remain VFR. High
confidence for coastal terminals to develop IFR ceilings after
sunset as well. Elsewhere is kind of a toss-up with most model
guidance (LAMP, HREF, REFS, & NBM) giving ~45-50% probabilities or
less, with the NBM and LAMP being the most pessimistic. As a result,
SCT007-010 decks were thrown in. If the stratus expands further
inland, BKN-OVC ceilings are likely to develop around the specified
times of the SCT cloud decks.
Vicinity of SFO...Moderate onshore breezes increase through the
afternoon. Low chance for gusts in excess of 25 kt at SFO today,
though sustained NW winds may increase to 15-18 kt and ease shortly
after sunset. Low confidence on IFR ceilings at SFO and OAK tonight.
Remained more optimistic this TAF period and hinted at the
possibility for IFR rather than locking it in. If ceilings do
develop they will likely develop later than last night around 10-12Z
Sunday and scatter out by 16-18Z tomorrow.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Clear skies prevail this afternoon with a
typical diurnal onshore breeze pattern. IFR ceilings will impact
both terminals around 03-06Z, though medium confidence on the exact
timing. Coastal drizzle/fog is possible overnight into early Sunday
morning and ceilings may intermittently drop to LIFR (OVC003-004).
The stratus is expected to scatter out by 18Z tomorrow.
&&
.MARINE...
(Today through Thursday)
Issued at 1155 AM PDT Sat Aug 1 2026
Widespread north-northwest strong to near gale force breezes
continue through the weekend. Frequent gale force gusts persist
across the northern waters and the Big Sur coast with a
possibility of occasional storm force gusts. Rough to very rough
wind driven seas, around 10-15 feet, continue to build today into
tomorrow and gradually subside early next week. Northern waters
will see the higher end of wave heights and winds. Conditions are
expected to decrease through the first half of next week. The
long period southerly swell continues to weaken through the
weekend.
&&
.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.
&&
.BEACHES...
Issued at 229 AM PDT Sat Aug 1 2026
Long period southerly to southwesterly swell continues through
the afternoon, bringing hazardous beach conditions to the Central
Coast and the San Francisco Bay Area. Southerly swell will weaken
by late this afternoon with conditions to drop below Beach
Hazards Statement criteria. Diminishing, low long period (1-2 ft
at 13 to 14 seconds) southerly swell will continue into next week.
Sneaker waves and strong rip currents will be the primary threats
through the duration of the Beach Hazards Statement, 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 until 5 PM PDT this afternoon for CAZ006-
505-509-529-530.
PZ...Gale Warning until 9 PM PDT Sunday for Pt Arena to Pt Reyes 0-10
nm.
Small Craft Advisory until 5 AM PDT Sunday for Pigeon Pt to Pt
Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 PM PDT this afternoon for Pt Pinos
to Pt Piedras Blancas 0-10 nm.
Gale Warning until 9 PM PDT this evening for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Gale Warning until 3 AM PDT Monday for Pt Arena to Pt Reyes 10-
60 NM.
Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Navarrete
MARINE...Navarrete
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Prepared by Boulder-Creek.com Weather at: Sat Aug 1 16:30:03 PDT 2026
From the National Weather Service
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