FXUS66 KMTR 060012
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
512 PM PDT Mon Oct 5 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1236 PM PDT Mon Oct 5 2026

 - Hazardous heat conditions inland persist through Thursday,
   never leave children or pets in unattended vehicles!

 - Elevated fire weather conditions persist in the interior
   through Thursday

 - Cooler temperatures possible late this week

&&

.SHORT TERM...
Issued at 1236 PM PDT Mon Oct 5 2026
(This evening through Tuesday night)

Stratus clouds lurk at the immediate coast, associated with a 
shallow marine layer around 500-1000 feet thick, but the rest of the 
region remains hot through the next couple of days as ridging 
persists across the western United States, ridging which is helping 
compress the marine layer and preventing any substantial overnight 
relief from reaching the higher elevations. To our northeast, high 
level clouds and convective remnants, associated with a puff of 
moisture riding an embedded low in the larger scale ridging, linger 
over the northern Sierra Nevada range and into the northern sections 
of the Great Basin. This time yesterday, that puff of moisture was 
streaming over the Bay Area, resulting in streaming high clouds that 
contributed to some cooler (relatively speaking) conditions than the 
expectation. Today the skies remain clear, and it's possible for 
today's high temperatures to overperform yesterday's, especially 
across the North Bay. High temperatures today and Tuesday range from 
the middle 90s to near 106 across the inland valleys, the middle 80s 
to the lower 90s near the Bays, and the upper 60s to the lower 70s 
along the Pacific coast. Mild overnight lows in the higher 
elevations, ranging from the upper 60s to the middle 70s, along with 
weak onshore flow will limit overnight recoveries. 

A Heat Advisory remains in effect for the interior regions, 
excluding the coastal strip and the northern Salinas Valley, as 
widespread Moderate HeatRisk blankets the interior, corresponding to 
a moderate risk of heat-related illnesses for sensitive populations, 
including children, the elderly, pregnant women, people with chronic 
illnesses, and people who work or live outdoors without access to 
adequate cooling or hydration. In addition, many of the higher 
elevations are seeing Major HeatRisk, corresponding to a high risk 
for heat-related illnesses for anyone without hydration or cooling. 
Follow these tips to avoid heat exhaustion and heatstroke:

* 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 1236 PM PDT Mon Oct 5 2026
(Wednesday through next Sunday)

Ridging persists for the next few days and the Heat Advisory has 
been extended to Thursday night for the inland and Bayshore regions. 
Temperatures across the inland valleys remain in the middle 90s to 
near 105 into Thursday; despite a couple of degrees of cooling on 
Thursday, hazardous heat lingers across the region and widespread 
Moderate HeatRisk persists in the inland regions. Patches of 
HeatRisk linger into Friday across the interior, and the Heat 
Advisory may need to be extended if confidence in heat-related 
impacts increases. 

Towards the latter part of the seven day outlook, uncertainty in the 
forecast increases as the ridge starts to break down and a trough 
begins to develop along the West Coast. Ensemble model cluster 
analysis suggests a split between solutions that bring something 
akin to an inside slider to the Great Basin for the upcoming weekend 
and those that keep the ridging in play. The inside slider solution 
slightly dominates the cluster space at this time, but we will wait 
for the model trend to become clearer before committing to a 
particular solution.

&&

.AVIATION...
(00Z TAFS)
Issued at 443 PM PDT Mon Oct 5 2026

Currently VFR everywhere except HAF where LIFR conditions have
developed. Largely expecting a shallow 500 ft marine layer to
remain in place today which will see a return of fog and IFR-LIFR
conditions to the coast. Guidance suggests some potential for 
lower ceilings/reduced visibility to reach STS, OAK, and SFO but 
confidence is low that this will occur. Conditions improve by late
tomorrow morning with VFR persisting through the remainder of the
day. Onshore winds remain between 10 to 16 knots during the day
tomorrow with lighter, variable winds overnight.

Vicinity of SFO...VFR. Onshore winds will diminish overnight
before increasing again during the day tomorrow. There is some
potential for MVFR conditions to develop between 09-17Z but
confidence is on the lower end. The shallow depth of the marine
layer should keep stratus/fog confined directly to the coastline
and prevent it from reaching SFO,

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Moderate onshore winds diminish this
evening with light, variable winds overnight. The stratus deck is
slowly expanding along the Monterey Peninsula coastline. It should
reach MRY around 02Z and SNS closer to 06Z. There is the potential
for it to arrive slightly earlier/later depending on how fast it
is able to spread. Fog becomes more likely after 06Z with highest
confidence in fog developing at MRY over SNS. Last night fog
temporarily developed at MRY but it looks to be more
widespread/consistent across the Monterey Peninsula tonight.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 443 PM PDT Mon Oct 5 2026

Gentle to moderate northwesterly breezes and slight to moderate
wave heights persist into midweek. Winds increase and wave heights
build, seas becoming rough across the outer waters, Friday into
the weekend. Additionally, increase southerly swell will impact
the coastal waters beginning Tuesday night and into the upcoming
weekend.

&&

.FIRE WEATHER...
Issued at 306 AM PDT Mon Oct 5 2026

Strong ridging aloft will lead to hot and dry conditions through 
Thursday with elevated fire weather conditions across the higher 
elevations. Poor to very poor overnight humidity recoveries will 
continue across the thermal belts with pushes of offshore flow 
each morning. Hazardous heat will continue through Thursday with 
major to extreme risks of heat-related illnesses across most 
mountain ranges. A pattern change later this week will bring 
cooler conditions to the region. 

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT Thursday for CAZ503-504-506-508-
     510-512>518.

PZ...None.
&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Kennedy
MARINE...RGass

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Prepared by Boulder-Creek.com Weather at: Mon Oct 5 18:30:03 PDT 2026