Technical NOAA Weather Discussion

FXUS66 KMTR 082341
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
441 PM PDT Wed Jul 8 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 228 PM PDT Wed Jul 8 2026

 - Warmer weather continues through the weekend

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

 - Coastal Flood Advisory for up to 1.7 feet of inundation above
   ground level is possible in low-lying areas near shorelines and
   tidal waterways

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

&&

.SHORT TERM...
Issued at 228 PM PDT Wed Jul 8 2026
(This evening through Thursday night)

Seasonally cool to seasonal temperatures continue through the 
remainder of today before a warming trend kicks off tomorrow. Upper 
level high pressure will continue to strengthen over the desert 
southwest as we head into Thursday. Temperatures are expected to 
warm by 2-5 degrees across the interior with most locations reaching 
the mid to upper 80s. Far northern North Bay and East Bay may reach 
the low to mid 90s with the interior Central Coast reaching the 
upper 90s to low 100s. If you're looking for cooler weather, coastal 
areas and the bay shoreline will stay in the 60s to 70s. HeatRisk 
remains Minor for most of the region with patchy Moderate HeatRisk 
forecast across the far interior Central Coast. As temperatures 
start to rise again, make sure to take breaks in the shade and stay 
hydrated while outdoors. Diurnally breezy winds continue in the 
afternoon and evening with gusts between 20 to 30 mph possible in 
favored windy locations (Altamont Pass, Salinas Valley). 

&&

.LONG TERM...
Issued at 228 PM PDT Wed Jul 8 2026
(Friday through next Tuesday)

The warming trend continues through the extended forecast period as 
high pressure remains in place over the desert southwest. Interior 
high temperatures may fluctuate a degree or two each day but will 
generally remain in the upper 80s to low 90s. Hot spots in the far 
North Bay, East Bay, and Interior Central Coast will be in the upper 
90s to low 100s. Coastal areas and the bay shoreline warm up 
slightly but will stay in the 70s (coast) to upper 70s/low 80s (bay 
shoreline). By late this weekend, the center of the upper level 
ridge will shift slightly northeastward over the Intermountain West 
where it will continue to strengthen heading into next week. 
Temperatures look to warm further early next week with Moderate 
HeatRisk forecast across portions of the Bay Area and higher 
elevations. Conditions do not currently meet Heat Advisory criteria 
but this may be reevaluated as we get closer in time.

Thunderstorms remain possible late this weekend into early next week 
as monsoonal moisture moves into California from the Gulf of 
California/Baja California. The moisture source remains good with
PWATs in excess of 1", about 150-200% or normal for this time of 
year. The 700-500 mb lapse rates remain around 7 C/km which is 
decent. The question becomes how much instability (MUCAPE) we will
have. Current models show isolated pockets of minimal MUCAPE 
across our region but this is by no means widespread or a 
substantial amount. Longer term models can sometimes struggle with
instability across our region so we will be able to better assess
this parameter as we move into the range of higher 
resolution/short term models. While we are still expecting little 
to no precipitation with this moisture surge, the ECMWF is showing 
the potential for some light rain (< 0.1") along the coast Sunday
into Monday. Fire weather concerns remain if thunderstorms are 
able to develop with storms possible across the Bay Area and 
Central Coast. It is recommended to stay up to date on the 
forecast especially as we get into the range of higher resolution 
models and get a better idea of the overall setup.

&&

.AVIATION...
(00Z TAFS)
Issued at 432 PM PDT Wed Jul 8 2026

The marine layer has compressed from about 1,500 feet yesterday to
about 1,000 feet today. That brings good news and bad news for
aviation weather. The good news is that the spatial and temporal 
stratus coverage will be reduced. The low clouds won't push as far
inland or last as long. The bad news is that where ceilings do
form, they will be closer to the ground. There is a good chance 
for IFR ceilings and even visibility impacts early Thursday 
morning, particularly where the winds ease overnight (looking at 
you, STS).

Vicinity of SFO...The clouds are currently banked up against the
Peninsula mountains. It's hard to say if they will spill over the
ridge like we saw the last couple days, or if they will have to
fill in the Bay side first. If they can't get over the ridge, that
would delay the onset by several hours and the terminal could stay
scattered until 08Z or so in the best case scenario. On the other
hand, the clouds could be there as soon as 02Z if they spill over,
which is my best guess based on the current satellite loop and
marine layer depth. 

SFO Bridge Approach...With either scenario described above, the
approach should stay clear several hours longer than the terminal
before the ceiling arrives early Thursday morning.

Monterey Bay Terminals...With the shallower marine layer the
ceilings should be 200-500 feet lower than last night, and there
is an outside chance for visibility impacts if the winds die down
more than expected at either MRY or SNS. 

&&

.MARINE...
(Tonight through next Monday)
Issued at 228 PM PDT Wed Jul 8 2026

Northwest winds remain fresh to strong as embedded near gale force
gusts increase into the weekend. Wind driven moderate seas (5-8
ft)  build to rough (9-11 ft) this evening into the weekend paired
with a  long period southerly swell.

&&

.FIRE WEATHER...
Issued at 254 PM PDT Wed Jul 8 2026

Warmer and drier conditions continue into this weekend. This
increases fire weather concerns slightly as fuels are forecast to 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. The main forecast concern is the lack of 
instability across our region which may prevent convection from 
developing. Given the combination of the potential for dry 
lightning and rapidly drying fuels, it is important to stay up to
date on the forecast as it evolves.

&&

.BEACHES...
Issued at 430 AM PDT Wed Jul 8 2026

A Beach Hazards Statement remains in effect for Pacific coast 
beaches 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.

A Coastal Flood Advisory is in effect for minor high tide 
flooding from Thursday July 9th through Thursday July 16th. The
combination of a perigean spring tide (lunar perigee on 7/13 and 
new moon on 7/14) enhanced by 3-6 inches of additional water from 
thermal expansion and accumulated sea level rise since the tidal 
datum was established (1983-2001) will bring high tides up to 1.7
feet above normal. This will lead to minor flooding of parking
lots, parks and roads with isolated closures expected. For
context, in June we reached 2.0 feet above normal.

&&

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

     Coastal Flood Advisory from 4 PM to 4 AM PDT Thursday for CAZ006-
     506-508.

     Coastal Flood Advisory from 8 PM Saturday to 4 AM PDT Wednesday 
     for CAZ505-509-529-530.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

     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.

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

     Small Craft Advisory until 9 PM PDT Thursday for Pigeon Pt to Pt 
     Pinos 0-10 nm.

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

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Flynn
MARINE...Navarrete

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Prepared by Boulder-Creek.com Weather at: Wed Jul 8 18:30:02 PDT 2026
From the National Weather Service