Technical NOAA Weather Discussion

FXUS66 KMTR 010728
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1228 AM PDT Sat Aug 1 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1251 PM PDT Fri Jul 31 2026

 - Gradual warming trend through the weekend 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
   Saturday

 - Strong and gusty winds develop over coastal waters north of
   Point Reyes this weekend

&&

.SHORT TERM...
Issued at 1200 AM PDT Sat Aug 1 2026
(Today and tonight)

What a difference 24 hrs makes. Last night we were monitoring heat
signatures from the Woodside Incident and a few patches of stratus
on the satellite. Tonight no heat signatures and stratus came back
with solid coverage over the coastal waters and locally inland.
Near-term hi-res models have a decent handle on the current
stratus pattern. The marine layer has deepened overnight to near
800-1000 feet. Expect stratus to linger into the morning then fade
pretty quick as a weak cold front approaches from the north. This
cold front will be dry in nature, but help mix out the marine
layer and set the stage for a rapid increase in N-S gradient. The
bigger impact to today weather wise will be the heat, especially 
the heat across the far interior. Regions that are being impacted 
by the marine layer have the best chance of fully tapping into the
850mb temps in the upper 20C range. That would push temps above 
100 again with the hotspots going for 110. Widespread HeatRisk of 
Moderate with some Major across interior Central Coast. Simply 
put, if you're doing outdoor activities away from the coast today 
be mindful and take some heat safety precautions. If you're 
seeking relief from the heat and want the natural AC at the coast 
you'll get it with highs in the 60s to 80s. Still energetic surf 
zone so use caution at the beaches. Beaches section below for more
info.

By this evening and early tonight the cold front will enter the
northern waters, but washout. The fading front will help to
establish a rapidly increasing N-S gradient from SFO-ACV. 
Previous projections put the gradient near -9mb, but tonight's 
model guidance have eased just under -8mb. Despite the drop, the 
increasing gradient will mix out the stratus and ramp up the wind.
Hi-res guidance still shows some dangerous Storm Force gusts 
north of Pt Reyes. Thankfully the strong winds stay mostly 
parallel to the coast. Aiding in less clouds tonight will also 
come from a weak burst of offshore flow over the N Bay and Central
Coast. 



&&

.LONG TERM...
Issued at 1200 AM PDT Sat Aug 1 2026
(Sunday through Friday)

Subtle cooling each day from Sunday through Wednesday thanks to a
flattening upper level ridge with a passing trough to the north.
Widespread Moderate HeatRisk across the interior will decrease in
coverage through Wednesday. Still expect breezy conditions each
afternoon/evening with onshore flow. The exception will be a
strong offshore flow burst Sunday night into Monday. Not strong
enough for a Wind Adv, but definitely elevate Fire Weather
concerns. 

Longer range guidance and official forecast shows a rebound in
temperatures Thursday and Friday as the ridge re-builds over the
region.

&&

.AVIATION...
(06Z TAFS)
Issued at 947 PM PDT Fri Jul 31 2026

MVFR/IFR ceilings have moved in sooner than expected across the
the Bay Area and into the Salinas Valley, right on time at KMRY.
Timing and extent of the stratus and coverage is still low
confidence with the compressed marine layer measured at about 
500-600 ft from the KOAK 00z balloon. Coverage overall is greater 
than at this time 24hrs ago. Breezy onshore flow will persist 
overnight and become gusty Saturday afternoon.

Vicinity of SFO...As mentioned above, stratus has spilled over 
and moved through the San Bruno Gap into the Bay sooner than 
expected. Expect MVFR ceilings to drop into IFR with breezy 
onshore flow persisting. Expect ceilings to lift to VFR by late 
morning with diurnally driven gusty onshore flow through the 
remainder of the TAF period.

SFO Bridge Approach...Similar as SFO.

Monterey Bay Terminals...MVFR/IFR ceilings are expected to 
persist through late Saturday morning with a slight chance of LIFR
late in the overnight through sunrise. Expect breezy onshore flow
to persist, especially Saturday afternoon with MVFR/IFR ceilings 
likely returning before sunset.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 947 PM PDT Fri Jul 31 2026

Big Sur coastal waters have begun to see an increase in northwest
winds this evening, becoming strong, with the remaining outer
waters and coastal waters seeing increases through the remainder
of tonight and Saturday. Strong to near gale gusts will persist
through the weekend in both the outer and coastal waters, then to
the northern outer waters for the beginning of next week. The
strengthening winds will also build seas from rough to very
rough, especially the northern outer zones on Sunday into Monday
(13-15 ft). Seas will gradually subside back to moderate the first
half of next week. Long period southerly swell will continue
through the weekend as well.

&&

.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 this afternoon for CAZ006-505-
     509-529-530.

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

     Gale Warning from 9 AM this morning to 9 PM PDT Sunday for Pt 
     Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 5 AM PDT Sunday for Pt Reyes to 
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM this morning to 5 AM PDT Sunday 
     for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Pinos 
     to Pt Piedras Blancas 0-10 nm.

     Gale Warning from 3 PM this afternoon to 9 PM PDT this evening 
     for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Warning from 9 AM this morning to 3 AM PDT Monday for Pt 
     Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt 
     Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...JM
MARINE...JM

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Prepared by Boulder-Creek.com Weather at: Sat Aug 1 00:30:03 PDT 2026
From the National Weather Service