FXUS66 KMTR 240542
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1042 PM PDT Fri Oct 23 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1038 PM PDT Fri Oct 23 2026
- Gusty offshore flow across the North Bay Interior Mountains
subsides late this morning
- Near normal temperatures this weekend into the beginning of
next week
- Coastal flooding due to astronomical high tides and thermal
expansion this weekend through Thursday
&&
.SHORT TERM...
Issued at 1038 PM PDT Fri Oct 23 2026
(Today and tonight)
Gusty offshore flow across the North Bay Interior Mountains is
ongoing tonight, with the windy and dry conditions dropping MinRH
values in the 20s for some locations. Fire weather concerns would be
higher for this area had we not received the recent wetting
rainfall. The offshore flow regime should mostly limit fog
development early this morning but still can't be ruled out entirely
in some of the river valleys in Sonoma County.
Temperatures today will be around 5 degrees warmer than Friday and
near normal for this time of year. The gusty winds across the North
Bay will begin to ease by late this morning, with a beautiful day in
store area wide across our CWA as upper level ridging builds
overhead.
&&
.LONG TERM...
Issued at 1038 PM PDT Fri Oct 23 2026
(Sunday through next Friday)
Sunday will almost be a carbon copy of today for the North Bay and
Bay Area, with the Central Coast seeing temperatures warm another
few degrees. Confidence and consensus in the synoptic pattern is
poor after Monday. An upper trough shifts south to our latitude on
Monday bringing a return of onshore flow, however the overall
progressive pattern is struggling with the depth of the trough and
how another system well offshore interacts with the flattening
trough as it moves into the Great Basin. Despite the uncertainty in
the overall pattern, any troughing or ridging will continue to be
progressive and low amplitude, with no large temperature fluctuations
or precipitation chances until the end of next week when the NBM
seems to pick up on what the current ECMWF deterministic has
depicted for next Friday into the weekend, troughing with increasing
rain chances.
&&
.AVIATION...
(06Z TAFS)
Issued at 827 PM PDT Fri Oct 23 2026
Surface high pressure will build into the Great Basin tonight and
Saturday morning. The WMC-SFO pressure gradient will steepen to near
10 mb while the RDD-SAC pressure gradient will steepen to around
3 mb. Offshore winds will develop in response to these gradients,
bringing in additional drying tonight and Saturday. Decreasing
water vapor will allow nocturnal radiational cooling to steepen
and residual humidity in the boundary layer from recent rain may
cool to saturation producing patchy low clouds and fog /IFR-LIFR/
tonight and Saturday morning. Radiative cooling will also produce
cool air drainage winds to the coastline tonight and Saturday
morning. Onshore winds closest to the coast will redevelop
Saturday, but not until later in the afternoon. Otherwise VFR is
forecast.
Vicinity of SFO...VFR. Northwest wind shifting to light northeast
wind by early Saturday morning. West to northwest wind near 10 knots
late Saturday afternoon and evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. West to northwest winds 5 to 10
knots shifting to east to southeast winds 5 to 10 knots tonight
and Saturday morning. Northwest winds near 10 knots late Saturday
afternoon and early evening.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 254 PM PDT Fri Oct 23 2026
Fresh to locally strong northerly winds will continue this
afternoon and evening. Near gale force to gale force gusts remain
possible across the far northern outer waters, with strong gusts
south of Pigeon Point. Northerly winds will continue to decrease
and become moderate by Saturday morning and then prevail through
the upcoming week. Rough seas are expected today and tomorrow
across the outer waters with wave heights peaking between 10 to 13
feet. Moderate seas prevail Sunday through much of next week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 8 AM Saturday to 3 PM PDT Thursday
for CAZ006-506-508-529-530.
Coastal Flood Advisory from 9 AM Monday to 3 PM PDT Thursday for
CAZ505-509.
PZ...Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt
Reyes 10-60 NM.
Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...Canepa
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Sat Oct 24 02:30:02 PDT 2026
From the National Weather Service
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