FXUS66 KMTR 191223
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
523 AM PDT Fri Jun 19 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 112 PM PDT Thu Jun 18 2026
- Hazardous beach conditions with increased risk of sneaker waves
and strong rip currents continue through the extended forecast
- Minor HeatRisk through the end of the week with below normal
temperatures expected this weekend
- Temperatures warm and Moderate HeatRisk concerns return by
midweek across the interior
&&
.SHORT TERM...
Issued at 1245 AM PDT Fri Jun 19 2026
(Today and tonight)
Stratus is filling back in once again early this morning as a
marine layer around 2500 feet deep resides over the area.
Additionally, satellite reveals scattered mid to high clouds
developing over the North Bay as an upper trough approaching the
coast taps into weak elevated instability. This will bring a very
low (generally less than a 5% chance) threat of showers and
thunderstorms, primarily to northern Napa and Sonoma counties.
While thunderstorms are unlikely, the trough will aid drizzle
development along the coast this morning. Despite light amounts,
any drizzle could make roadways slick.
The trough, deep marine layer, and onshore winds will continue the
cooling trend today. Highs near the coast will range from the
upper 50s to around 70 degrees, with highs inland reaching the
70s to low 80s. These values are near to slightly below normal
along the coast, but 5-15 degrees below normal inland. Clouds
should recede this afternoon, but may hang on along the coast as
moderate to strong onshore flow interacts with terrain. Winds this
afternoon and evening will be breezy, especially through
gaps/passes in terrain and near Monterey and San Francisco Bays
where gusts 20-30 mph are possible. Tonight, expect stratus to
redevelop within the marine layer with areas of drizzle along the
coast.
The long-period southerly swell will continue to bring a risk for
sneaker waves and strong rip currents, with a Beach Hazards
Statement out through late Saturday night. See the BEACHES
section for more information, but the main takeaway is to never
turn your back to the ocean!
&&
.LONG TERM...
Issued at 1245 AM PDT Fri Jun 19 2026
(Saturday through Thursday)
Temperatures will remain below normal on Saturday as a trough
lingers along the coast. Coastal drizzle is also possible within
the marine layer Saturday morning. By Sunday, the trough will
start to weaken and the marine layer should begin to compress.
This will begin a warming trend, especially inland, where highs
will reach the mid 70s to upper 80s, and even a few readings
around 90 degrees in the warmest locations. The warming trend will
continue early next week as a ridge builds across the western
U.S. Confidence is high in hotter inland temperatures, with highs
in the 80s and 90s becoming common Tuesday through Thursday and
an increased concern for Moderate HeatRisk. Near the coast,
confidence in the temperature forecast is low to moderate, but
some warming is expected. More significant warming would likely be
tied to a weaker onshore or even offshore wind pattern, which is
low confidence at this time. The warming trend is definitely worth
keeping an eye on and is a reminder that, despite our currently
below normal temperatures, impacts from heat will become more
likely next week.
Finally, by Wednesday and Thursday, a minority of ensemble
guidance indicates a plume of elevated instability rotating around
the upper level ridge (centered over the Desert Southwest) and
across the Central Coast and Bay Area. While confidence in this
pattern is very low (currently around a 10% chance of
occurrence), it bears monitoring as thunderstorms would be
possible in this scenario.
&&
.AVIATION...
(12Z TAFS)
Issued at 423 AM PDT Fri Jun 19 2026
Ongoing -RA/-DZ across much of the region with sufficiently deep
marine layer. Bases currently hovering right around 1500-2000ft
MSL, with stratus expected to begin eroding out 16-18z for inland
terminals. Clouds should clear from the coastal sites today,
around 20-21z for MRY and SNS, with moderate confidence in at
least brief clearing at HAF around the same time. Gusty southwest
to west winds develop this afternoon around 20z for most locations,
with intermittent gusts up to 25-30kts in some spots. Conditions
will be largely VFR this afternoon with FEW high clouds AOA
20,000ft MSL this morning and afternoon. Winds expected to weaken
after 04-05z Sat, and similarly based marine layer will move
inland around the same time. Clouds expected to reach as far
inland tonight as they did this morning, with -DZ/-RA possible
once again.
Vicinity of SFO...BKN stratus based ~2000ft MSL will prevail
through around 15/16z before starting to scatter out, but unlikely
to clear completely until closer to 21z. VFR prevailing
thereafter with FEW high clouds. Breezy southwest winds develop
around 19/20z with gusts up to 25kts, briefly closer to 30kts,
through 04z Sat. Marine layer stratus moves back in again after
05z, filling into the terminal fully closer to 09z with similar
depth.
SFO Bridge Approach...Patchy low level clouds along the approach
with bases generally around 1800-2000ft MSL. Clouds will continue
to fill in through 14z before beginning to clear out, with stratus
lingering in the vicinity through around 20z or so. Breezy west-
southwest winds develop around 21z, prevailing through 04z Sat
with gusts around 25kts. Patchy marine layer clouds move back in
with similar bases after 08z.
Vicinity of SJC and OAK...Intermittent MVFR CIGs will continue for
both locations through 17/18z when they will scatter out. VFR
prevailing thereafter with FEW high clouds. Breezy west to
northwest winds develop after 20z with gusts up to 25kts this
afternoon before weakening around 05z. Marine stratus returns with
bases around 2000ft MSL, filtering into OAK around 05z Sat and
pushing into SJC closer to 09z.
Monterey Bay Terminals...-DZ with a marine layer depth of around
2000ft. Scattering out will occur around 18-20z, with generally
VFR for the afternoon. Breezy winds for both terminals, with gusts
around 20-24kts through the early evening. Low clouds will begin
to move in again around 03z with bases around 2000ft MSL, filling
into the terminals fully by 06-08z.
&&
.MARINE...
(Today through Wednesday)
Issued at 423 AM PDT Fri Jun 19 2026
Light winds early this morning increase this afternoon becoming
fresh to strong out of the W/SW into the early evening hours with
hazardous conditions for small crafts in the San Francisco Bay,
Suisun Bay, San Pablo Bay and Monterey Bay. Expect moderate chop
at times with the increasing winds this afternoon and evening.
Long period southwest swell will continue into the weekend with
moderate W/SW winds across the outer waters. Winds ease Saturday
then increase across the outer northern water early Sunday into
the beginning of next week.
&&
.BEACHES...
Issued at 1245 AM PDT Fri Jun 19 2026
Long period southerly swell at around 15 to 17 seconds will persist
through early Sunday as energetic storms in the Southern
Hemisphere continue to affect the California coast, especially for
south and southwest facing beaches. Hazardous beach conditions
are advertised, specifically for moderate to steeply sloped
beaches along the Pacific Coast of the North Bay, San Mateo, Santa
Cruz counties. A Beach Hazards Statement for Pacific Coast
beaches continues through late Saturday night. Be sure to check
beach conditions before you head out. Sneaker waves will run up
the beach much farther than other waves, potentially catching
beachgoers by surprise and resulting in people being swept into
the water. Rip currents are strong enough to pull the strongest
swimmers away from shore. Swim near a lifeguard if possible. Stay
back from the beach, and away from jetties, piers, beachside
rocks, and other infrastructure near the water. Never turn your
back to the ocean!
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through late Saturday night for CAZ006-
505-509-529-530.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
evening for Mry Bay-SF Bay N of Bay Bridge.
Small Craft Advisory from 9 PM Saturday to 3 AM PDT Monday for
Pt Arena to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...Tangen
LONG TERM....Tangen
AVIATION...Zuber
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Fri Jun 19 08:30:02 PDT 2026
From the National Weather Service
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