FXUS66 KMTR 071704
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1004 AM PDT Wed Oct 7 2026
...New AVIATION, MARINE...
.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
&&
.UPDATE...
Issued at 957 AM PDT Wed Oct 7 2026
The morning fog has cleared. Outside of the immediate coast north
of Pigeon Point, expect another day of clear skies and warm
temperatures. The Heat Advisory remains in effect through 10 PM
Thursday for inland areas. The weather gets very interesting this
weekend with a drastic cool-down, strong winds, coastal flooding,
and some remnant moisture from Tropical Storm Rachel. Could it
rain on Monday? More to come on these topics with the afternoon
discussion.
&&
.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...
(18Z TAFS)
Issued at 1004 AM PDT Wed Oct 7 2026
Patchy fog and LIFR stratus lingers at the immediate coast with the
rest of the region remaining VFR through the daytime. A gentle to
moderate onshore pattern wind develops in the afternoon and
evening hours. Overnight stratus development is limited to the
immediate coastal region, with a low confidence for radiational
fog development at STS. Some clearing will occur late Thursday
morning close to the end of the TAF period.
Vicinity of SFO... High confidence for VFR conditions through the
TAF period. Moderate west-northwest winds will develop in the
afternoon and evening hours, with light winds overnight into the
morning.
SFO Bridge Approach... Similar to SFO
Monterey Bay Terminals... VFR conditions through the rest of the
daytime with a gentle to moderate northwest winds in the afternoon
and evening hours. LIFR stratus will develop in the evening hours
with moderate confidence for fog development, lower confidence in
the clearing tome on Thursday morning.
&&
.MARINE...
(Today through Monday)
Issued at 1004 AM PDT Wed Oct 7 2026
Gentle to moderate north breezes and moderate seas prevail
through Thursday. Strong to near gale force north winds will
develop across the northern outer waters Friday, spreading across
the rest of the waters this weekend. Rough to very rough seas will
build Friday into the weekend as a result. Long period southerly
swell arrives Friday with long period westerly swell arriving
Sunday.
&&
.FIRE WEATHER...
Issued at 410 AM PDT Wed Oct 7 2026
Hot and dry conditions will lead to elevated fire weather conditions
across the higher terrain through Thursday. Temperatures 10 to 20
degrees above normal and poor minimum relative humidity will
continue away from the compressed marine layer at the coast. The
higher terrain will experience active thermal belting, little-to-no
recovery with nocturnal drying across the highest peaks, and thus
prolonged burn periods. Winds remain the limiting factor, with
diurnal winds prevailing except for light northerly/offshore flow
overnight across the higher terrain. ERC values will rise to near
records during the hot and dry conditions. A pattern change Friday
into the weekend will bring cooler, moister, and windier
conditions.
Sarment
&&
.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...JM
LONG TERM....JM
AVIATION...DialH
MARINE...DialH
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Prepared by Boulder-Creek.com Weather at: Wed Oct 7 12:30:04 PDT 2026
From the National Weather Service
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