FXUS66 KMTR 211137
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
437 AM PDT Sat Mar 21 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 301 AM PDT Sat Mar 21 2026

 - Much cooler, but still above average temperatures today

 - Continued cooling for Sunday

 - Dry weather at least through the end of the month

&&

.SHORT TERM...
Issued at 301 AM PDT Sat Mar 21 2026
(Today and tonight)

The transition from ridging and high pressure to a modest zonal flow 
is already affecting temperatures. A map of 24 hour temperature 
change shows most areas around 5 degrees cooler than this time last 
night, with portions of the Big Sur Coast around 20 degrees cooler 
as the thermal belt erodes. 

The marine layer is also redeveloping, leading to some pockets of 
coastal fog and stratus along the coast of Monterey Co and around 
Half Moon Bay. The reducing pressure will allow the marine layer to 
expand through the morning, and hints at a weak southerly surge of 
stratus along the Big Sur. Areas affected by this push of stratus 
look to have much cooler temperatures than previous days, but this 
will be focused on the immediate coast. 

The rest of the region will still see a notable cooldown today as 
the pressure reduces and slight onshore flow develops. Highs will 
range 5 to 15 degrees cooler than previous days, with the low 60s on 
the coast, 70s for areas slightly more inland, and the 80s for the 
more interior areas. This will still be roughly 5 to 10 degrees 
above average for the non-coastal areas, but will be a welcome 
change of pace from the hazardous, record-breaking heat of the work 
week. 

&&

.LONG TERM...
Issued at 301 AM PDT Sat Mar 21 2026
(Sunday through Friday)

The cooling trend continues into Sunday with highs and lows reducing 
by a few more degrees. But this is where our pattern looks to hold 
steady. Our zonal to slight ridging pattern continues through the 
next work week, keeping highs and lows fairly similar from day to 
day. Some spots in the Bay Area will see only a 3 degree difference 
from the warmest day to the coolest day. 

Chances for coastal drizzle have fizzled out as Wednesday's cold 
front has pushed farther north in more recent model update. With 
those chances out of the forecast, it looks like it might not be 
until the very end of the month before chances for rain return to 
the forecast. Some of the extended term models still show a 
developing trough pushing a weak low pressure into the Bay Area into 
April. But even the most optimistic models only show chances for 
scattered light rains as this low weakens as it approaches.

&&

.AVIATION...
(12Z TAFS)
Issued at 437 AM PDT Sat Mar 21 2026

It's VFR except for patchy coastal fog and stratus /LIFR-IFR/ 
this morning. Gusty west to northwest winds developing later in
the morning and afternoon. 

Vicinity of SFO...VFR. West wind increasing to 15 to 25 knots
later today and into the evening, then decreasing to 10 to 15
knots tonight and Sunday morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR except a patch or two of fog and 
stratus /LIFR-IFR/ this morning. West to northwest winds 
increasing to 10 to 20 knots today. Winds decreasing to light and
variable tonight and Sunday morning.

&&

.MARINE...
(Today through Thursday)
Issued at 301 AM PDT Sat Mar 21 2026

Strong northerly winds will spread across the waters today through
tonight. Frequent gale force gusts are expected across the outer
waters and in the Point Reyes coastal jet region with isolated
gale force gusts expected from Point Reyes to Point Piedras
Blancas.  Hazardous seas are expected over the weekend as a
result. Winds  diminish and seas abate early next week then
increase again mid week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PDT this morning for Pigeon Pt 
     to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Gale Warning from 9 AM this morning to 3 AM PDT Sunday for 
     Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Reyes to 
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM this morning to 3 AM PDT Sunday 
     for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras 
     Blancas 0-10 nm.

     Gale Warning until 9 AM PDT Sunday for Pt Arena to Pt Reyes 10-
     60 NM.

&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...Canepa
MARINE...Canepa

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Prepared by Boulder-Creek.com Weather at: Sat Mar 21 06:30:03 PDT 2026