FXUS66 KMTR 070808
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
108 AM PDT Wed Oct 7 2026

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

.KEY MESSAGES...
Updated at 0103 AM PDT Wed Oct 7 2026

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

 - Elevated fire weather conditions persist in the interior
   through Thursday

 - Coastal flooding concerns due to astronomical tides and thermal
   expansion through the weekend

 - Hazardous beach conditions along Pacific coastline later this
   week into the weekend due to long period swell

&&

.SHORT TERM...
Issued at 103 AM PDT Wed Oct 7 2026
(Today and tonight)

The marine layer remains shallow and compressed tonight with only
inland intrusion on satellite over the Monterey Bay into the 
Salinas Valley. KHAF is reporting 1/4mi vis in fog, KOAR is 
reporting 1/2mi and KMRY is down to a mile vis, thus can't rule 
out another Dense Fog Advisory along the Pacific Coast at some 
point over the remainder of the overnight into Wednesday morning.

The Heat Advisory remains in effect with high pressure still 
draped over our area, however later tonight, a weak upper level 
disturbance begins to encroach on the ridging pattern as it moves 
east today. Marginally improved onshore flow will bring more 
stratus into the North Bay and Bay Area later tonight than we've 
seen the past few nights, with the potential for more widespread 
impacts from fog possible into Thursday morning.

&&

.LONG TERM...
Issued at 103 AM PDT Wed Oct 7 2026
(Thursday through Tuesday)

Although the aforementioned weak upper level disturbance will help 
break down the ridge it won't ultimately make it to the coast, 
instead it will be pulled south into a merger with the remnants of 
Rachel by the weekend. The hot temperatures will linger Thursday 
with no changes anticipated for the Heat Advisory to come to an end 
Thursday night.

The cooler temperatures through the weekend will be welcomed as 
temps return to more seasonal averages. An interesting synoptic 
pattern begins to unfold by Sunday into the beginning of next 
week. A series of mergers is set in motion, beginning with Rachel 
moving onshore. The Polar Jet trough absorbs the remnants of 
Rachel while moving entirely over our area (was farther east in 
prior deterministic output) with increasing confidence in 
scattered light rain, especially for the Central Coast Sunday 
night into Monday. While the upper level low producing our 
rainfall begins its shift east it will then merge with 
'Disturbance 1' as it moves into the Desert Southwest. The upper 
level low impacting us this weekend will bring gusty winds into 
our typical valleys, gaps and passes with very strong winds 
possible above 50 MPH for elevated portions of the East Bay both 
Friday night and Saturday night.

&&

.AVIATION...
(06Z TAFS)
Issued at 940 PM PDT Tue Oct 6 2026

Stratus and fog along the coast, largely VFR across the interior. 
The question becomes if fog will reach STS as webcams show fog 
developing upstream along the Russian River. If fog does reach STS 
it likely won't be until the early morning hours so have included a 
tempo for fog from 13-17Z. Elsewhere, not expecting fog/stratus to 
reach SFO or OAK tonight given the shallow marine layer. LIFR to IFR 
conditions are expected at HAF, MRY, and SNS with dense fog likely 
to develop. Guidance is indicating an early clearing of fog (15-17Z) 
for coastal areas. Moderate onshore winds continue during the 
afternoon and evening with lighter, variable winds overnight.

Vicinity of SFO...VFR through the TAF period. The shallow marine 
layer should keep fog from reaching SFO with guidance showing some 
potential for stratus to return late tomorrow night. Onshore winds 
strengthen late afternoon/evening with winds around 18 knots 
expected. 

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR to IFR conditions expected overnight 
as dense fog develops along the coast. Bumped up the timing of fog 
arrival at SNS and MRY with arrival now around 08Z. Guidance shows 
clearing around 15-16Z tomorrow morning with stratus likely to 
return tomorrow evening. LAMP guidance supports an earlier return 
but other models are still uncertain. Have included a SCT cloud deck 
for 03Z tomorrow night in the current TAFs but this is likely to be 
adjusted as models get a better idea of when stratus will return 
tomorrow night.

&&

.MARINE...
(Tonight through next Monday)
Issued at 940 PM PDT Tue Oct 6 2026

A gentle to moderate northerly breeze continues through Thursday
due to persistent high pressure. Strong to near gale force winds
develop Friday evening continuing over the weekend as an coastal
level trough moves in. Strongest winds will be over the outer
waters north of Point Reyes. Moderate seas prevail through
Thursday, building and becoming rough to very rough Friday into
Saturday. A confused sea state will develop late week due to
moderate to long period westerly swell entering the coastal
waters.

&&

.FIRE WEATHER...
Issued at 456 AM PDT Tue Oct 6 2026

Maximum and minimum temperatures 10 to 20 degrees above normal
across the interior with a compressed marine layer at the coast 
will persist through Thursday. Widespread poor minimum relative 
humidity is expected across the interior with little-to-no 
recovery for the higher terrain. Active thermal belting and prolonged
burn periods will continue across the higher terrain. Winds 
remain the limiting factor, with diurnal winds prevailing except
for light northerly/offshore flow overnight across the higher
terrain. ERC values are forecast to reach near records during the
next seven days from the hot and dry conditions. An inside slider
like pattern succeeding this heat event will likely keep elevated
fire weather conditions around. 

&&

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

     Coastal Flood Advisory until 1 PM PDT Thursday for CAZ506.

PZ...None.
&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...JM
MARINE...JM

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Prepared by Boulder-Creek.com Weather at: Wed Oct 7 02:30:02 PDT 2026