FXUS66 KMTR 171640
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
940 AM PDT Wed Jun 17 2026

...New UPDATE, MARINE...

.KEY MESSAGES...
Updated at 1245 AM PDT Wed Jun 17 2026 

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

 - Hazardous beach conditions through early Thursday morning with
   increased risk of sneaker waves and strong rip currents.

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

&&

.UPDATE...
Issued at 924 AM PDT Wed Jun 17 2026

Forecast remains generally on track. However, marine stratus looks
to linger a bit longer into the late morning and afternoon hours for
the San Francisco Bay area on north as onshore marine push is a
bit more robust. Dropped high temperatures couple of degrees for 
areas north of the San Francisco Bay as a result. Areas south of 
the bay are seeing stratus retreat back towards the coastline this
morning. 

&&

.SHORT TERM...
Issued at 1245 AM PDT Wed Jun 17 2026 
(Today and tonight)

A marine layer 1000-1500 feet deep will bring extensive cloud
cover to the coast and adjacent valleys this morning. Patchy
drizzle has been observed along the coast and will continue 
through the morning, especially over the higher terrain. By the 
afternoon, clouds should retreat back to the coastline with mostly
sunny skies. The marine influence combined with breezy onshore 
winds this afternoon will keep areas near the coast relatively 
cool, with highs mainly in the 60s to lower 70s. Overall, 
conditions will be very similar to Tuesday. Marine stratus will 
return tonight, along with patchy drizzle redeveloping along the 
coast.

High pressure over the area will start to weaken today, which 
will bring about 2-5 degrees of cooling inland. This will place
temperatures near normal for mid June with highs in the upper 70s
to lower 90s. Most areas will see Minor HeatRisk today with only 
isolated pockets in the interior of Moderate HeatRisk. Despite the
slight cooling, continue to practice smart heat safety 
(especially for those more sensitive to the heat) by limiting time
outdoors, taking frequent breaks in the shade (if outdoors), and 
staying hydrated.

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 tides are expected to 
be 1.7 ft above normal (7.5 ft MLLW) at 12:56 AM early this
morning, and 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 Thursday 
morning. 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 Wed Jun 17 2026 
(Thursday through Tuesday)

A trough off the coast will approach the area on Thursday and
further weaken the ridge. This will continue the cooling trend
across inland areas, with highs dropping by around 5 degrees. The
trough will begin to move onshore on Friday. 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 
a 5% chance of thunderstorms across far northern Napa and Sonoma 
counties Thursday night and Friday with lower chances to the 
south.

The trough will help to deepen the marine layer Friday into the 
weekend with breezy onshore afternoon/evening winds. The inland 
cooling trend will continue with highs Friday and Saturday only 
reaching the 70s to low 80s at the warmest locations, or about 5 
to 15 degrees below normal. Coastal areas will remain relatively
cool due to the marine influence. Drizzle may also develop over 
the coastal waters and along the coast. Troughing will weaken by 
Sunday with ensembles in agreement that a ridge will rebuild 
across the West early next week. This will bring a warming trend, 
especially inland.

&&

.AVIATION...
(12Z TAFS)
Issued at 429 AM PDT Wed Jun 17 2026

Satellite shows low clouds have filtered in sufficiently this
morning, with CIGs currently at all TAF sites, mostly low- end 
MVFR. Stratus has made it into LVK and SJC, likely to prevail 
there through 15-16z this morning. Intermittent -DZ possible at 
times this morning and again Thursday morning. The low clouds 
retreat back to the coast beginning around 16z, and VFR should 
prevail for all but the immediate coastal sites after 18z and into
the afternoon as gusty seabreeze winds return. Gusts around 15kts
through the afternoon, with highest confidence at SFO and APC. 
The marine layer will filter in again tonight with slightly lesser
chances to reach LVK and SJC, which are expected to remain VFR 
for Thursday morning (moderate confidence). 

Vicinity of SFO...BKN-OVC stratus with bases around 1200ft MSL 
will prevail through 16z before slowly retreating back towards 
the coastline, potentially lingering nearby through 20-21z. Gusty
westerly winds increase around 20z, with intermittent gusts up to
18kts through 07z Thur before weaker Thursday morning. Similar 
gusts for Thursday afternoon. Stratus fills in again after 07z 
Thurs, although MVFR CIGs may occur as late as 09z. Clearing 
likely by 15-16z Thur. 

SFO Bridge Approach...Stratus will clear this morning at a similar
time as the terminal, 16-17z with VFR prevailing thereafter.
Lesser chances for clouds Thursday morning with likely SCT MVFR
for the bridge approach. 25-40% chance of BKN/OVC closer to
sunrise on Thursday. 

Vicinity of SJC and OAK...Stratus with bases around 1000-1400ft
MSL will clear by 15-16z from SJC, around 2 hours before OAK, 
with VFR for the afternoon. Gustier northwest winds develop after 
20z, as high as 15kts. MVFR stratus will push into the area after 
05z, although likely hold out from OAK until after 08z. Model 
guidance puts chances for a CIG at SJC Thursday morning at around 
10-15%, but confidence is low to moderate for this given that 
stratus overperformed this morning. 

Monterey Bay Terminals...BKN-OVC bases 1000-1300ft MSL continue
until around 17z, but stratus will remain in the vicinity into the
afternoon, especially for SNS. Low clouds with similar bases moves
into the terminals again this evening, potentially as early as 
00z Thur for SNS, likely closer to 02z for MRY, prevailing through
all of Thursday morning. 

&&

.MARINE...
(Today through Monday)
Issued at 924 AM PDT Wed Jun 17 2026

Winds have mostly subsided this morning, with onshore pushes
maintaining moderate to fresh southwest winds for San Francisco
and San Pablo Bays through the afternoon and evening hours.
Onshore winds will impact the near coastal areas of Point Sur
north to Point Pinos, and Pigeon Point to the Golden Gate. Fresh
to locally strong onshore winds in the afternoons and evening
will continue for the San Francisco Bay, San Pablo Bay, Monterey
Bay, along with the near coastal area near Point Sur daily
through at least the end of the workweek. Elsewhere, expect light
to gentle winds for the reminder of the week into the weekend
with light to moderate seas and weak southwesterly swell across
the coastal waters.

&&

.BEACHES...
Issued at 1245 AM PDT Wed Jun 17 2026 

Long period southerly swell at around 15 to 17 seconds will persist 
through early Thursday 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 5 AM Thursday morning. 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 tonight for CAZ006-505-509-
     529-530.

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

PZ...None.
&&

$$

UPDATE...Slagle 
SHORT TERM...Tangen 
LONG TERM....Tangen 
AVIATION...Zuber 
MARINE...Barislavich

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Prepared by Boulder-Creek.com Weather at: Wed Jun 17 10:30:02 PDT 2026