FXUS66 KMTR 090503
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1003 PM PDT Thu Oct 8 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 927 PM PDT Thu Oct 8 2026
- Sharp cool-down this weekend and early next week
- Coastal flooding during high tides and large swell this weekend
- Beach Hazards Saturday morning until Monday afternoon
- Light rain possible north Central Coast early next week
&&
.SHORT TERM...
Issued at 1243 PM PDT Thu Oct 8 2026
(This evening through Friday night)
A Heat Advisory remains in effect until 10 PM this evening for
much of the interior Bay Area and Central Coast as 500 mb high
pressure remains in place over the region. Temperatures across the
interior will be in the some 10-20 degrees F above seasonal
averages again this afternoon with cooler conditions near the
coast given the shallow marine layer around 500 feet in depth.
Overnight temperatures will still remain warm in the higher
terrain tonight with 60s to low 70s expected and generally in the
50s in the lower elevations. This is as a mid/upper level trough
begins to develop off of the British Columbia coastline and allows
for the marine layer to deepen.
Friday will be noticeable cooler as the aforementioned trough
deepens along the West Coast bringing temperatures closer to
normal for this time of year. Thus, expecting temperatures to cool
into the low-to- upper 80s in the inland valleys and the warmest
interior portions of the region to reach into the lower 90s.
Breezier onshore winds are also expected on Friday afternoon and
evening along the coast and wind-prone gaps, passes, and valleys.
This will keep temperatures near the coast in the 60s to lower
70s.
A Coastal Flood Advisory remains in effect for bayshore locations
adjacent to the San Pablo Bay with up to 1.2 feet of inundation
above ground level in low-lying areas during times of peak high
tides. On Friday morning, the areas adjacent to the San Francisco
Bay and Monterey Bay are added to the advisory through at least 3
PM Tuesday.
&&
.LONG TERM...
Issued at 1243 PM PDT Thu Oct 8 2026
(Saturday through next Wednesday)
Additional cooling is expected by Saturday as a dry frontal
boundary drops southward across the Bay Area and Central Coast and
the mid/upper level trough deepens along the West Coast. Thus,
temperatures will cool to below seasonal averages Saturday through
early next week. Onshore winds will be a bit stronger than those
on Friday with gusts between 30-40 mph along the coast and in the
wind- prone gaps, passes, and valleys. Locally stronger gusts will
be possible in these areas this weekend.
The NBM and global forecast models continue to indicate a chance
for rain showers across the southern portion of the Bay Area and
Central coast Sunday evening through Monday. This is as an upper
level cut- off low pressure system and remnant moisture from
Tropical Storm Rachel push into the Central Coast. However, not
expecting widespread measurable rainfall at this time. Winds ease
late Sunday and into early next week as the through axis shifts
inland. Cooler conditions are forecast to persist through midweek
as troughing persists over the West Coast. Then, as we head into
the latter part of the upcoming week, a gradual warming trend is
forecast by the WPC Cluster Analysis as high pressure builds in
from the eastern Pacific.
&&
.AVIATION...
(06Z TAFS)
Issued at 1003 PM PDT Thu Oct 8 2026
VFR everywhere except for HAF, MRY, and SNS where LIFR-IFR
conditions prevail through Friday morning. Fog development is
possible overnight at these sites, including STS, though low to
medium confidence on the exact timing. Overnight, winds remain light
and gradually increase to a moderate onshore breeze Friday afternoon
with locally stronger winds at SFO. The anticipated cold frontal
passage is complicating the ceiling forecast tonight and Friday
evening. The marine layer will deepen, but it will likely remain too
shallow to reach the interior East and South Bay valley terminals.
Moderate confidence for IFR ceilings at OAK and LIFR ceilings at the
coastal sites plus STS.
Vicinity of SFO...VFR. Northwest winds gradually ease overnight. Low
confidence on stratus impacts at SFO with scattered decks more
likely. OAK continues to have a higher chance of borderline IFR-MVFR
ceilings that will mix out by late Friday morning. Northwest winds
increase that afternoon and remain elevated through the evening as
the cold front passes through the region.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...IFR ceilings will gradually drop to LIFR
overnight, resulting in foggy/misty conditions through Friday
morning. Low to medium confidence on the exact timing of visibility
reductions. VFR prevails Friday afternoon once onshore winds
increase to around 10 kt. IFR ceilings are likely to return around
sunset again on Friday.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 1003 PM PDT Thu Oct 8 2026
Hazardous marine conditions begin Friday through the weekend.
North to northwesterly breezes increasingly become strong to near
gale force as a cold front approaches the coast. Very rough wind
driven seas build up to 15 feet with a low long period southerly
swell arriving on Friday, which is then replaced by a moderate
rough long period westerly swell on Sunday. Marine conditions
gradually improve early next week as northwest winds ease.
&&
.FIRE WEATHER...
Issued at 428 AM PDT Thu Oct 8 2026
Hot and dry conditions will lead to elevated fire weather conditions
across the interior and higher terrain Thursday. Temperatures 10 to
20 degrees above normal and poor minimum relative humidity will
continue away from the compressed marine layer at the coast
Thursday. 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. Even
though conditions become cooler and more humid Friday, windier
conditions will keep elevated fire weather conditions across the
interior and higher terrain through Friday.
Sarment
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 9 AM Friday to 3 PM PDT Tuesday for
CAZ006-508-529-530.
Beach Hazards Statement from Saturday morning through Monday
afternoon for CAZ006-505-509-529-530.
Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.
PZ...Small Craft Advisory from 3 PM Friday to 3 AM PDT Saturday for
Pt Arena to Pt Reyes 0-10 nm-SF Bay N of Bay Bridge.
Small Craft Advisory from 3 AM Friday to 3 AM PDT Saturday for
Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 PM Friday to 3 AM PDT Saturday for
Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Navarrete
MARINE...Navarrete
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Prepared by Boulder-Creek.com Weather at: Thu Oct 8 22:30:04 PDT 2026
From the National Weather Service
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