Technical NOAA Weather Discussion

FXUS66 KMTR 240013
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
513 PM PDT Fri Oct 23 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1200 PM PDT Fri Oct 23 2026

 - Gusty offshore flow across the North Bay Interior Mountains 
   this evening through Saturday morning

 - Below normal temperatures today, increasing to near normal for
   the weekend

 - Coastal flooding due astronomical high tides and thermal 
   expansion this weekend through at least the middle of next week

&&

.SHORT TERM...
Issued at 1200 PM PDT Fri Oct 23 2026
(This evening through Sunday)

Mostly clear sky conditions are expected by this afternoon across 
all of the Bay Area and north Central Coast as high pressure over 
the eastern Pacific builds and shifts eastward. However, the 
presence of the exiting trough will keep conditions slightly below 
seasonal averages. As a separate mid/upper level cut-off low moves 
into the northern portion of the Intermountain West, we will have a 
brief period of moderate offshore winds (locally strong in the 
highest peaks) across the North Bay Interior Mountains with 
northeasterly gusts to around 30-40 MPH late this evening and into 
Saturday morning. Again, the highest peaks have the potential to 
exceed 50 MPH. Elsewhere across the Bay Area, offshore winds will be 
weaker but still exist in elevations generally above 1,000 feet. 
Given the offshore flow aloft over much of the Bay Area, have lower 
confidence of fog development again overnight. That said, cannot 
rule out fog again over the North Bay Interior Valleys just before 
sunrise Saturday morning. 

Saturday and Sunday afternoon maximum forecast temperatures will 
warm to near to slightly above seasonal averages as high pressure 
continues to build over the eastern Pacific. However, minor coastal 
flooding looks to return to bayshore locations along the San Pablo 
Bay, San Francisco Bay, and Monterey Bay on Saturday and then low-
lying areas along the Pacific Coast Monday during and around times 
of peak high tide. This is due to thermal expansion of the warm 
waters generated by El Nino and astronomical high tides through at 
least the middle of next week. 

&&

.LONG TERM...
Issued at 1200 PM PDT Fri Oct 23 2026
(Sunday night through next Thursday)

Temperatures drop to slightly below normal for much of next week as 
a series of troughs impact the Pacific Northwest. Thus, we are not 
expecting any precipitation until late in the week and into the 
following weekend (October 30th-November 1st). This is the time 
frame in which the Climate Prediction Center's 6-10 and 8-14 Day 
Outlooks give the Bay Area and north Central Coast a 50-60% 
probability of above normal precipitation which is more typical for 
a strong El Nino year as the Pacific jet stream drops farther south 
over southern California. Be sure to stay up-to-date with the latest 
forecast information from trusted sources. 

&&

.AVIATION...
(00Z TAFS)
Issued at 513 PM PDT Fri Oct 23 2026

It's VFR across the forecast area. Surface high pressure will 
build into the Great Basin tonight and Saturday morning. This will
steepen the WMC-SFO pressure gradient 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 a patch or two of 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 PM PDT this evening for Pigeon Pt 
     to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos 
     to Pt Piedras Blancas 0-10 nm.

     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...RGass
LONG TERM....RGass
AVIATION...Canepa
MARINE...KR

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Prepared by Boulder-Creek.com Weather at: Fri Oct 23 18:30:03 PDT 2026
From the National Weather Service