FXUS66 KMTR 221752
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1052 AM PDT Thu Oct 22 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1202 AM PDT Thu Oct 22 2026

 - Rain showers continue through this afternoon

 - A warming and drying trend expected for the upcoming weekend into
   early next week

&&

.UPDATE...
Issued at 922 AM PDT Thu Oct 22 2026

Rain showers continue over the North Bay, portions of the San 
Francisco Bay Area, and out over the Pacific this morning. As the 
low pressure system begins to progress inland over the south Central 
Coast/southern California through the day. There is generally a 10%-
15% chance of thunderstorms across the north Central Coast, East 
Bay, and South Bay as Surface Based CAPE (Convective Available 
Potential Energy) is forecast to increase up to 500 J/kg across 
these regions given daytime heating. With the loss of daytime 
heating, rain showers will be limited to the Big Sur Coastline late 
tonight.

RGass

&&

.SHORT TERM...
Issued at 1202 AM PDT Thu Oct 22 2026
(Today and tonight)

Primary concern in the short term remains rainfall from the upper 
level low just offshore of the Central Coast into early this 
morning. The window for a chance of low-top supercells and the 
accompanying severe threat has closed with just light rain expected 
for spots that see any rainfall over the next 24hrs or so. The slow 
moving upper level system is still expected to produce anywhere from 
0.10"-0.50" for most spots over the course of the day today, with 
coastal areas assisted by upslope flow to see the highest totals. 
The rainfall on the back side of the system should taper off entirely 
by sunset tonight and drier conditions filling in amid subsidence on 
the backside of the exiting wave.

&&

.LONG TERM...
Issued at 1202 AM PDT Thu Oct 22 2026
(Friday through Wednesday)

PWATs begin to drop more considerably later in the day and evening 
Friday indicating further drying conditions and warmer temperatures 
for the weekend into the beginning of next week. However, temperatures
for the weekend into the beginning of the work week will hover 
right around normal for this time of year, with no big warmup 
indicated under relatively low amplitude, progressive ridging 
through the middle of next week when troughing begins to develop 
well offshore. 

&&

.AVIATION...
(18Z TAFS)
Issued at 1045 AM PDT Thu Oct 22 2026

Low conf today on exact timing and clouds/vis details given
transient nature of showers/rain as a low pressure meanders
eastward through the region today. For the general picture mostly
MVFR to VFR conditions with pockets of IFR with RA and -SHRA.
Gradual diminishing of precip by this evening. Post system regime
will feature cooling and damp low level late tonight ad early
Friday. As such, some radiation FG is poss for STS with low
strato-cu at other terminals early Friday.  

Vicinity of SFO...VFR to MVFR with poss -SHRA through early this
evening. Behind the showers low conf, but have MVFR CIGs 
overnight and early Friday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR to MVFR with poss -SHRA through early this
evening. Behind the showers low conf, but have MVFR CIGs 
overnight and early Friday. Winds become more diurnal with 
drainage winds by early Friday for SNS.

&&

.MARINE...
(Today through Tuesday)
Issued at 1045 AM PDT Thu Oct 22 2026

Active weather over coastal waters and bays today with showers and
thunderstorms as a storm system lingers. Expect gusty, erratic
winds if a thunderstorm or stronger shower develops. Marine
thunderstorm chances peak early Thursday morning with thunderstorm
chances shifting over the inner waters/over land during the
afternoon. Moderate northerly breezes gradually return today with
strong to near gale force gusts increasing across the outer waters
Thursday through Saturday. Moderate seas build, becoming rough to
very rough across the outer waters Friday into Saturday before
abating Sunday into next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 PM this evening to 3 AM PDT Friday 
     for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 9 AM PDT Friday 
     for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras 
     Blancas 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 3 AM PDT 
     Saturday for Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 9 PM this evening to 9 PM PDT Friday 
     for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...MM
MARINE...MM

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Prepared by Boulder-Creek.com Weather at: Thu Oct 22 12:30:03 PDT 2026