FXUS66 KMTR 190828
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
128 AM PDT Fri Jun 19 2026
...New SHORT TERM, LONG TERM...
.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...
(06Z TAFS)
Issued at 935 PM PDT Thu Jun 18 2026
Breezy winds easing this evening though still persistent through
the night into the day on Friday. Low clouds continue to fill much
of the area terminals. MVFR will remain in place through tonight
into the morning hours with slow clearing expected 16-20Z for
areas closer to the coast. Confidence in marine layer depth and
inland spread is moderate to high and should be similar to what
was observed earlier this morning, potentially slightly deeper.
Vicinity of SFO...Breezy southwest winds subsiding after 08Z.
The marine layer will begin to move back inland, with MVFR cigs
around 1500-1700ft likely reaching the terminal by around 07-08Z
with moderate confidence on timing and cig heights. Conditions
will improve again after sunrise, with cigs forecast to erode by
16-18Z Fri.
SFO Bridge Approach...Lingering clouds over the bay may
continue to reduce visibility overnight. Otherwise, conditions
should be similar to SFO.
Vicinity of SJC and OAK...Low clouds near 1500ft will move into
OAK over the next couple of hours with lower confidence in cigs
near 2000ft reaching SJC in the 11-15z time frame. Typical diurnal
winds expected on Friday.
Monterey Bay Terminals...Marine stratus will continue to fill in
over the region with cigs near 1000-1500ft overnight into Friday.
morning. Moderate confidence in clearing time on Friday near 19-20Z
Fri.
&&
.MARINE...
(Today through Tuesday)
Issued at 849 PM PDT Thu Jun 18 2026
Fresh to strong winds have been gradually weakening and will
continue into the night. Fresh to strong winds will return Friday
afternoon and early evening leading to hazardous conditions for
small crafts in the San Pablo Bay, San Francisco Bay, Suisun Bay
and Monterey Bay. Expect slight to moderate chop along with the
increasing afternoon winds each day. Southwesterly swell with
light to moderate seas will continue into the weekend, with
moderate west to southwest winds across the outer waters.
&&
.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 to 9 PM PDT Friday for Mry Bay-SF
Bay N of Bay Bridge.
&&
$$
SHORT TERM...Tangen
LONG TERM....Tangen
AVIATION...Roser
MARINE...Malarkey
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Prepared by Boulder-Creek.com Weather at: Fri Jun 19 04:30:03 PDT 2026
From the National Weather Service
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