Technical NOAA Weather Discussion

FXUS66 KMTR 032344
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
444 PM PDT Sat Oct 3 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 111 PM PDT Sat Oct 3 2026

 - Moderate to major HeatRisk across the Bay Area and Central Coast 
   today and Sunday 

 - Moderate to major HeatRisk across the interior Bay Area and 
   Central Coast Monday through Thursday

 - Elevated fire weather conditions across the higher terrain 
   through Thursday

 - Potential for a pattern change late week and into the weekend

&&

.SHORT TERM...
Issued at 111 PM PDT Sat Oct 3 2026
(This evening through Sunday night)

The morning started off with stratus and reduced visibilities 
starting along the San Francisco coast to the Big Sur Coast. 
Unfortunately, this was short lived as clouds and fog mixed out 
right around sunrise, leading to sunny skies for much of the 
morning. Temperatures have responded accordingly, exceeding their 
initial forecast earlier this morning. Attempted to adjust them with 
the late morning forecast package update, but even then some sites 
will likely exceed their forecast highs. Looking to tomorrow, the 
forecast should be similar if not hotter meaning temperatures may 
need to be bumped for coastal locations. For now, opted to keep the 
Heat Advisory that was issued for Sunday the same and not include 
the southern portion of the Monterey Bay. However, should 
temperatures continue to exceed their forecast amount, they may need 
to be added tomorrow. 

All that to be said, we're in the beginning of the heat wave and 
Moderate to Major HeatRisk is expected for Sunday. Make sure to beat 
the heat by practicing heat safety. You can visit weather.gov/safety 
for more information, but here a few quick handy tips. 

* 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.

&&

.LONG TERM...
Issued at 111 PM PDT Sat Oct 3 2026
(Monday through next Friday)

The heat continues into the upcoming work week and with confidence 
increasing in where it'll happen, the Heat Advisory for the interior 
Bay Area and interior Central Coast has been extended until 10PM 
Wednesday. Additional areas may need to be added to it, with the 
highest confidence being for the northern Monterey Bay region. 
Elsewhere, like San Francisco, Marin, and the southern Monterey Bay, 
confidence remains moderate to low thus we opted to hold out on 
extending or adding these beyond Sunday. Nonetheless, it'll be hot, 
so please continue to take precautions and practice heat safety to 
avoid heat exhaustion and heat stroke.

Looking at the end of the week, around Friday and into next weekend, 
ensembles continue to trend towards cooler weather. The current 
forecast, if we don't stay in a ridging pattern, has much of the 
region in Minor HeatRisk. Highs continue to trend in the mid 60s to 
low 70s along the coast, the upper 70s to mid 90s for interior 
valley locations, and the 80s to mid 90s for higher elevations. 
Ensembles and guidance show either zonal flow or the beginning of 
troughing starting to form. Timing and placement is still a bit iffy 
as to when any sort of trough makes it here, but it's something 
we'll keep an eye. 

&&

.AVIATION...
(00Z TAFS)
Issued at 442 PM PDT Sat Oct 3 2026

VFR everywhere with onshore breezes around 6 to 12 kt. Similar to 
last night, light and variable winds are expected through the 
overnight hours, which increase again and become onshore by late 
Sunday morning. Given the shallow marine layer, almost all terminals 
will remain VFR through the TAF cycle. Low to medium confidence on 
whether LIFR stratus/fog will develop at HAF and MRY.

Vicinity of SFO...High confidence for VFR conditions to prevail 
through the TAF period. Northwest to westerly breezes ease by sunset 
and gradually shift to a bay breeze at SFO early Sunday morning. 
Northwest winds increase by the afternoon with high clouds cruising 
through most of the day on Sunday.

SFO Bridge Approach...Minor reductions to visibility (5-6SM HZ) are 
possible through the afternoon and improve after sunset. Otherwise, 
similar to SFO.

Monterey Bay Terminals...North to northwesterly breezes persist into 
the evening with stronger winds at SNS. Overnight, drainage winds 
settle into the Salinas Valley. MRY has a higher chance of 
developing LIFR ceilings/fog compared to SNS, though confidence is 
low to moderate. Strong high pressure persists over the region which 
will limit the extent of the shallow marine layer. If ceilings or 
fog develop, it will be short-lived with VFR prevailing by early 
Sunday morning. 

&&

.MARINE...
(Tonight through next Thursday)
Issued at 442 PM PDT Sat Oct 3 2026

Northerly to northwesterly breezes will remain gentle to moderate
into much of next week, allowing for slight to moderate seas to
persist.

&&

.FIRE WEATHER...
Issued at 111 PM PDT Sat Oct 3 2026

Hot and dry conditions are forecast through Thursday, which will 
be accompanied with weak offshore flow. Poor to very poor 
overnight recovery is expected for the thermal belts, generally 
for elevations above 1000-1500 feet, leading to elevated fire 
weather conditions. The marine layer is expected to be confined to
the immediate coast and around 500 feet. A pattern change is
expected late in the week, which should start to bring cooler 
weather and the potential for improved RH recovery on Friday. 

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT Sunday for CAZ006-502-528-529.

     Heat Advisory until 10 PM PDT Wednesday for CAZ503-504-506-508-
     510-512>518.

PZ...None.
&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Navarrete
MARINE...RGass

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Prepared by Boulder-Creek.com Weather at: Sat Oct 3 18:30:04 PDT 2026
From the National Weather Service