Technical NOAA Weather Discussion

FXUS66 KMTR 072039
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
139 PM PDT Tue Jul 7 2026

...New FIRE WEATHER...

.KEY MESSAGES...
Updated at 1253 PM PDT Tue Jul 7 2026

 - Seasonably cool temperatures today before a warming trend
   begins Wednesday through the weekend

 - Long period southwest swell causes an increased risk of sneaker
   waves and strong rip currents today through Friday

 - Potential for thunderstorms and elevated fire weather concerns
   late this weekend into early next week

&&

.SHORT TERM...
Issued at 1253 PM PDT Tue Jul 7 2026
(This evening through Wednesday night)

Seasonal to seasonally cool temperatures continue today into 
tomorrow thanks to a deep marine layer and expansive layer of marine 
stratus. The marine layer is forecast to remain between 1500-2000 
feet through tomorrow as troughing continues to our west over the 
Pacific Ocean. Marine stratus will return across much of the 
interior Bay Area and Central Coast tonight with pockets of fog 
possible across the North Bay Valleys and along the coast. If you 
are missing clear skies today, you will have a better chance at 
seeing them tomorrow. Confidence is higher tomorrow that stratus 
will recede by late morning/early afternoon across the interior as 
surface high pressure strengthens and the marine layer compresses to 
around 1000-1500 feet. The marine layer will help keep much of the 
area seasonally cool with high temperatures in the 50s to 60s along 
the coast and 70s to 80s across the interior Bay Area. The one 
exception will be the interior Central Coast where temperatures are 
seasonal to seasonally warm in the 80s to 90s. Marine layer 
influence on the interior Central Coast is minimal with building 
high pressure across the desert southwest having a stronger 
influence on that region. Breezy afternoon and evening winds 
continue across mountain gaps/passes (the Salinas Valley, San Bruno 
Gap, the Altamont Pass) and along the coast. 

&&

.LONG TERM...
Issued at 1253 PM PDT Tue Jul 7 2026
(Thursday through next Monday)

The forecast begins to change Wednesday night into Thursday as high 
pressure across the Desert Southwest retrogrades, becoming centered 
more over Southern California. This allows temperatures to warm up 
by a few (~4-5) degrees outside of coastal areas and the bay 
shoreline. For the interior Bay Area this results in temperatures in 
the mid to upper 80s with pockets of 90s in the far North Bay and 
far interior East Bay. The warmest locations will be in the interior 
Central Coast where temperatures look to be in the low 100s Thursday 
and Friday. The NBM deterministic is running closer to the 90th 
percentile for the interior Central Coast but even the mean NBM 
forecast keeps temperatures around 100. All that to say, 
whatever way you look at it the interior Central Coast will be hot 
on Thursday. Temperatures will remain fairly similar to this through 
the rest of the extended forecast as upper level ridging builds over 
California. High temperatures will fluctuate by 1-2 degrees but will 
largely stay in the 80s to low 90s across the interior, 60s along 
the coast, 70s along the bay shoreline, and 90s to low 100s across 
the interior Central Coast. Long range models are showing early 
potential for strong upper level ridging to build across the 
Intermountain West early to mid next week. This is likely to bring 
above normal temperatures with initial guidance for Tuesday showing 
temperatures warming across the interior East Bay and interior 
Central Coast. This is certainly something to keep an eye on if not 
for the heat impacts but the fire weather risk. 

In addition to the hotter conditions expected in the long term, 
there is the potential for dry lightning Sunday into Monday. On the 
synoptic scale, upper level high pressure will more northeastward 
(towards the Intermountain West) Sunday into Monday while upper 
level troughing deepens over the Pacific Ocean. Our region is still 
primarily influenced by the upper level ridge, but, the deepening 
trough will result in stronger southeasterly flow across Southern 
California, Arizona, and the Gulf of California. This will bring a 
surge of monsoonal moisture from the Gulf of California northward 
into California. PWAT values look to be between 1-1.5" Sunday into 
Monday which is approximately 150-200% of normal for this time of 
year. The highest PWAT values are currently forecast across the 
Central Coast, South Bay, and East Bay. At the same time, the 700-
500 mb lapse rates are between 7-8 C/km which are favorable for 
convection to develop. If all these ingredients are able to come 
together, then it is likely we would see high-based thunderstorms 
across portions of our CWA. Given the elevated nature of any 
potential thunderstorms, any precipitation that falls would 
evaporate before reaching the surface. The two most likely hazards 
would then be dry lightning and gusty, erratic outflow winds. Hot 
and dry conditions this week will prime the environment for fire 
starts by further drying out fuels and making them more susceptible 
to fire starts if thunderstorms develop. Fire weather concerns are 
elevated Sunday into early next week as a result of the dry 
lightning threat. While the pattern appears conducive for 
thunderstorm development, there remains some uncertainty regarding 
specific details. The nature of these specific details may modulate 
the risk for a high-based convective event.  

This is a good time to stay tuned to the forecast as we move into 
the domain of higher resolution short term models and the forecast 
becomes clearer later this week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1130 AM PDT Tue Jul 7 2026

A persistent stratus deck, characterized by IFR to MVFR ceilings
will continue to gradually erode from east to west this 
afternoon. However, the clearing trend has been slow and 
confidence is a little lower than normal with regard to specific 
times, particularly at coastal sites. While VFR is advertised 
between 20Z-23Z this afternoon at all TAFs, it's quite probable 
that it's short-lived. Persistent onshore flow is forecast to 
translate into an early evening (01Z-05Z) return of MVFR and IFR 
ceilings. The potential for LIFR ceilings and IFR visibility is 
greatest at HAF, STS, and APC, though low confidence precludes 
mention in the TAFs at this time. Higher confidence does exist in 
VFR by 21Z Wednesday, but for most locales, this is after the 
current valid TAF cycle. 

Vicinity of SFO...MVFR is forecast to prevail through 21Z, though
confidence is low to medium. Winds are anticipated to funnel 
through the gap with peak gusts just under 30 knots this 
afternoon. While there remains uncertainty in VFR this afternoon,
confidence is high that MVFR will be in place by 03Z. Despite the
forecast of lower near surface moisture (relative to Tue AM), IFR
is forecast during the pre-dawn hours on Wed as onshore flow 
persists. There's a greater chance for VFR Wed afternoon with 
medium to high confidence.

SFO Bridge Approach...VFR will return 1 to potentially 2 hours
ahead of the main terminal this afternoon. Otherwise, similar to
SFO.

Monterey Bay Terminals...MVFR currently, but the VFR potential is
greatest at SNS as the eastern edge of a stratus bank erodes. 
Intermittent MVFR is forecast through mid-afternoon here. An eddy 
has developed near OAR and provide favorable trajectories for a 
persistent fetch of MVFR stratus into MRY thru the afternoon. If 
this eddy dissipates, however, clearing may transpire and VFR 
could return to MRY sooner than forecast. Trends will be 
monitored. IFR is forecast to make a return this evening between 
03-04Z. Occasional-DZ cannot be discounted (and thus IFR 
visibility) at MRY. At this time, confidence is too low to 
include. IFR ceilings are forecast to lift into MVFR toward the 
end of the TAF period, though eddy development may alter the 
timing.

&&

.MARINE...
(Today through Sunday)
Issued at 916 AM PDT Tue Jul 7 2026

Moderate to strong breezes are forecast across area waters,
including the bays over the next 24 hours. Northwesterly swell
between 6 and 8 feet will continue, with approximately 2 to 3
foot secondary long period southerly swell persisting through the
week. While winds diminish to largely gentle breezes across bays,
strong breezes and rough seas will persist through early Thursday
across the Pacific coast waters.

&&

.FIRE WEATHER...
Issued at 127 PM PDT Tue Jul 7 2026

Warmer and drier conditions return Thursday and continue into this
weekend. This will increase fire weather concerns slightly as 
fuels rapidly dry across the interior. Fire weather concerns 
further increase late this weekend into early next week as a surge
of monsoonal moisture from the Gulf of California brings the 
potential for high based convection to the region. If 
thunderstorms are able to develop, dry lightning and gusty, 
erratic outflow winds would be the main hazards. The current 
pattern looks conducive for thunderstorms to develop but this may 
change as the event gets closer in time. Given the combination of 
potential for dry lightning and dry fuels, it is important to stay
up to date on the forecast for the latest information.


&&

.BEACHES...
Issued at 1238 PM PDT Mon Jul 6 2026

A Beach Hazards Statement remains in effect for Pacific coast 
beaches from Tuesday morning through Friday afternoon. Long period
southwesterly swell will create an increased risk of sneaker 
waves and strong rip currents, as well as breaking waves up to 10 
feet. This will be especially true for south and southwest facing 
beaches with moderate to steep slopes along the North Bay, San 
Francisco Peninsula, and Santa Cruz coasts. Sneaker waves can 
sweep across the shoreline without warning, pulling people into 
the sea from rocks, jetties and beaches. Dangerous swimming and 
surfing conditions and localized beach erosion can be expected. 
Stay off of jetties, piers, rocks, and other waterside 
infrastructure. Remain out of the water to avoid hazardous surf 
and NEVER turn your back on the ocean. Monitor local weather, surf
and tide forecasts at www.weather.gov/mtr.

&&

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

PZ...Small Craft Advisory until 3 AM PDT Wednesday for SF Bay N of 
     Bay Bridge.

     Small Craft Advisory until 9 PM PDT Wednesday for Mry Bay.

     Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt 
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt 
     Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 AM PDT Thursday for Pt Reyes to 
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt 
     Pinos 0-10 nm.

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

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Bain
MARINE...Bain

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Prepared by Boulder-Creek.com Weather at: Tue Jul 7 16:30:03 PDT 2026
From the National Weather Service