FXUS66 KMTR 172317
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
417 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...
(00Z TAFS)
Issued at 417 PM PDT Wed Jun 17 2026

MVFR-IFR stratus is confined to the immediate coast with breezy 
onshore winds  with a southerly component and strong gusts through 
the evening hours. Generally MVFR with some borderline IFR stratus 
will return to the North Bay, central SF Bay, and Monterey Bay 
terminals overnight 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. May need to 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 conditions at present with breezy and 
southwest winds in place through the evening. MVFR-IFR stratus moves 
in overnight with impacts expected by 07-09Z. 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 to early Friday morning, right at or after 
the end of the TAF period.

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... VFR with breezy northwest winds at both 
terminals through the evening hours. At OAK, MVFR-IFR stratus should 
flow into the terminal area this evening with moderate confidence of 
impact timing, as high resolution models generally aim for the 02-
05Z timeframe. At SJC, there is much less confidence in the stratus 
forecast. High resolution model output keeps the terminal area 
clear, but places scattered stratus in the vicinity and particularly 
to the north of the terminal. This may need to be watched closely 
during the night. Stratus will dissipate through the course of 
Thursday morning, with breezy and possibly gusty winds developing 
through the afternoon. Winds remain northwesterly at OAK but 
moderate confidence for southwest flow at SJC.

Monterey Bay Terminals... VFR conditions at the moment with breezy 
southwest winds at MRY and northwest winds with strong gusts at SNS 
continuing into the evening hours. MVFR-IFR stratus will come over 
both terminals within the next couple of hours and persist through 
the night. Stratus will retreat to the immediate coast Thursday 
morning with winds during the afternoon exhibiting a similar pattern 
to today's winds.

&&

.MARINE...
(Tonight through next Monday)
Issued at 417 PM PDT Wed Jun 17 2026

Moderate to fresh west/southwest winds in the bays will diminish
around sunset this evening. Winds increase again for the next
couple afternoons and evenings with strong breezes anticipated,
leading to hazardous conditions for small crafts. Light to
moderate seas with southwesterly swell will continue into the
weekend. Moderate west/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...Berislavich

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Prepared by Boulder-Creek.com Weather at: Wed Jun 17 16:30:02 PDT 2026