FXUS66 KMTR 180458
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
958 PM PDT Wed Jun 17 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 156 PM PDT Wed Jun 17 2026

 - Minor coastal flooding due to higher than normal high tides
   anticipated across low-lying coastal areas.

 - Hazardous beach conditions as well with increased risk of 
   sneaker waves and strong rip currents.

 - Minor HeatRisk through the end of the week with temperatures
   cooling to below normal.

&&

.SHORT TERM...
Issued at 156 PM PDT Wed Jun 17 2026
(This evening through Thursday night)

The marine layer, ~1500ft, continues to retreat back towards the 
coast, having lingered a bit longer than expected for the San 
Francisco Bay and into the northern interior valley, bringing 
slightly cooler high temps for today. Expect the marine layer to 
push back onshore tonight. Have included drizzle along the coast 
as the marine layer slightly deepens as the ridge breaks down as 
troughing pushes east towards the coast. Patchy fog for interior
valleys possible as well. The slight cooling trend will continue 
into Thursday, especially for interior locations, as a result of 
the troughing and slightly stronger onshore flow, with afternoon 
highs in the 60s along the coast to mid 70s to 80s for interior 
locales. The marine layer builds to ~2000kt and expands further 
inland for tomorrow night, with more fog and drizzle expected.

Tidal flooding continues across low-lying coastal and Bayshore 
areas through Thursday morning as high astronomical tides combine 
with surge effects from wind, swell, and thermal expansion to 
bring us the highest tides of the summer season. High tide is 
expected to be 1.2 ft above normal (7.1 ft MLLW) at 1:51 AM on 
Thursday. In addition, the long-period southerly swell continues, 
which increases the risk for sneaker waves and strong rip 
currents, with a Beach Hazards Statement out through late Friday
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 156 PM PDT Wed Jun 17 2026
(Friday through Wednesday)

The trough will begin to move onshore on Friday and pass over the
region through the weekend, with the cooling trend continuing. 
Shower and thunderstorm potential associated with the trough will
stay primarily over the higher terrain to the north and east of 
the area as a deep marine layer greatly inhibits any thunderstorm 
potential. However, there will be enough elevated instability for
cumulus development and around a 5% chance of thunderstorms 
across far northern Napa and Sonoma counties Thursday night and 
Friday with lower chances to the south.

The marine layer will likely deepen as the trough passes through,
with the cooling trend continuing through Saturday. Afternoon 
highs temps will only reach the 70s to low 80s for interior 
location and upper 50s to mid 60s along the coast. The onshore 
flow will continue with breezy afternoon winds. Coastal areas will
could continue to see drizzle.

By Sunday, the trough is expected to weaken as model guidance is
suggesting a ridge building across the western US into next week.
This will bring a warming trend, beginning Sunday into next week,
with a return of some 90s and moderate HeatRisk concerns by 
midweek for some interior areas.

&&

.AVIATION...
(06Z TAFS)
Issued at 958 PM PDT Wed Jun 17 2026

MVFR-IFR stratus is expanding into the valleys and will impact most 
terminals through the night as the breezy and gusty southwest 
pattern winds continue to diminish, with low to moderate confidence 
in stratus impacts at LVK and SJC, where the marine layer is thick 
enough to bring stratus into both terminals but the lower level 
southwest flow may inhibit stratus flow into those areas. The night 
shift will monitor conditions through the night. Stratus should 
retreat to the coastal areas through Thursday morning and the breezy 
and gusty southwest pattern winds should resume in the afternoon.

Vicinity of SFO... VFR with breezy and gusty southwest winds at the 
terminal through the next few hours. Due to the downslope flow, have 
pushed back the MVFR-IFR stratus impacts to around 10Z. Stratus will 
dissipate through Thursday morning with breezy southwest winds 
returning to the terminal in the afternoon. Stratus will return to 
the terminal area late Thursday night.

SFO Bridge Approach... Lower confidence of stratus impacts tonight 
with the large scale southwest flow, as high resolution models tend 
to keep the stratus deck away from the approach path. Otherwise 
similar to SFO.

Vicinity of OAK and SJC... IFR stratus through the night at OAK, 
with breezy west winds diminishing through the next couple of hours. 
At SJC, the stratus forecast remains low confidence. High resolution 
model output keeps the terminal area clear, but places scattered 
MVFR stratus in the vicinity and particularly to the north of the 
terminal. If stratus does impact the terminal, the most likely 
timing is from 11-15Z. Stratus clears out through Thursday morning 
as breezy and gusty winds return to the terminals, with west winds 
developing at OAK, and southwest winds developing at SJC. Stratus 
returns to OAK late Thursday night.

Monterey Bay Terminals... MVFR stratus has flowed over SNS and will 
remain through the night. At MRY, large scale southwest flow has 
sheltered the terminal from the larger stratus deck, defying much of 
the high resolution model output, but a patch of stratus developing 
to the immediate southeast of the terminal suggests that the 
ceilings are close by. Stratus will retreat to the immediate coast 
Thursday morning and will return to the terminals Thursday evening. 
Breezy winds will diminish through the night before resuming on 
Thursday afternoon with strong gusts and a turn from a southwest 
wind at MRY and a northwest wind at SNS.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 958 PM PDT Wed Jun 17 2026

West to southwest winds driven by a weak low pressure system in
the northern outer waters will remain gentle to moderate
overnight. Winds increase again for the next couple afternoons and
evenings with strong breezes anticipated, leading to hazardous
conditions for small craft. Light to moderate seas with
southwesterly swell will continue into the weekend. Moderate  west
to southwest winds and moderate seas will prevail over the  open
ocean into the weekend.

&&

.BEACHES...
Issued at 156 PM PDT Wed Jun 17 2026

Long period southerly swell at around 15 to 17 seconds will persist 
through early Saturday 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 Friday 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 Friday night for CAZ006-505-
     509-529-530.

     Coastal Flood Advisory until 5 AM PDT Thursday for CAZ006-506-
     508.

PZ...Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Mry Bay-
     SF Bay N of Bay Bridge.

&&

$$

SHORT TERM...Slagle
LONG TERM....Slagle
AVIATION...DialH
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Wed Jun 17 22:30:03 PDT 2026