FXUS66 KMTR 200815
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
115 AM PDT Sat Jun 20 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1245 AM PDT Sat Jun 20 2026

 - Hazardous beach conditions with increased risk of sneaker waves
   and strong rip currents continue through the extended forecast

 - Minor HeatRisk with below normal temperatures through the 
   weekend

 - Warmer temperatures and Moderate HeatRisk concerns return by 
   midweek across the interior

&&

.SHORT TERM...
Issued at 1245 AM PDT Sat Jun 20 2026
(Today and tonight)

The pattern overall will remain similar today as a broad upper 
level trough sits overhead. Stratus will expand across most areas
this morning within a marine layer around 3000 feet deep. Drizzle
may develop along the coast this morning as well, resulting in 
locally slick roadways. The deep marine layer and continued 
onshore flow will keep temperatures similar to yesterday, with 
highs along the coast ranging from the upper 50s to around 70. 
Inland, temperatures will remain below normal with highs reaching 
the 70s to lower 80s. Clouds should retreat back to the coast this
afternoon, giving way to sunny skies in most areas. However, 
clouds may not fully erode in coastal areas due to onshore flow 
and orographic effects. Onshore winds will once again be breezy 
this afternoon and evening with gusts 15-30 mph, strongest in 
gaps/passes.

The marine layer will begin to compress tonight as the upper 
level trough weakens. Marine stratus will still fill in most 
valleys tonight, but the extent should be lower overall. Patchy 
fog will also be possible along the coast and in wind-sheltered 
valleys.

&&

.LONG TERM...
Issued at 1245 AM PDT Sat Jun 20 2026
(Sunday through Friday)

The upper level trough will continue its weakening trend on Sunday
and the marine layer will compress further. Decreasing marine 
influence and warming temperatures aloft will begin a warming 
trend, especially inland, where many locations will reach the 80s,
with a few readings approaching 90 degrees in the warmest spots. 
The warming trend will continue Monday and Tuesday as a broad 
ridge builds across the western U.S. Highs will reach the 80s and 
90s through the week across the interior. Hot temperatures will be
accompanied by the potential for Moderate HeatRisk and increased 
heat impacts, although overnight cooling limits concerns somewhat.
Closer to the coast, confidence in the temperature forecast is 
lower, but at least some warming is expected. More significant 
warming along the coast/SF Bay shoreline could develop if a weaker
onshore or offshore wind pattern occurs, but confidence in this 
scenario is low. This potential will continue to be monitored as 
we head into next week.

As mentioned in previous discussions, ensemble guidance continues
to indicate moisture rotating north around the upper ridge 
centered over the Desert Southwest. By Wednesday and Thursday, 
there is a low (around 10%) chance that the moisture and 
accompanying instability makes it far enough west to bring a 
threat for thunderstorms to the Bay Area and Central Coast. 
Overall, the chance of this scenario occuring is low, but it 
could have a large impact. While the current forecast package does
not include thunderstorms, this potential will continue to be 
closely monitored over the coming days. 

&&

.AVIATION...
(06Z TAFS)
Issued at 953 PM PDT Fri Jun 19 2026

The marine layer has begun to move onshore with patchy stratus
developing near SJC, LVK, and SNS will result in widespread MVFR 
ceilings across the region. Coastal sites may see some drizzle 
around sunset time through midnight. Any accumulating 
precipitation is expected to remain very light, between 0.02-0.03 
inches, and may cause a slight reduction in visibility. Stratus
will recede back off land around 18 to 19Z Saturday.  

Vicinity of SFO...SW winds are gradually weakening in the area 
and will continue into the overnight hours returning after 20Z
Saturday. As the marine layer deepens to around 2500 feet 
overnight, MVFR ceilings are expected to impact the terminal as 
early as 08Z Saturday and persist through 19Z Saturday.

SFO Bridge Approach...SW wind and gusty pattern is similar to SFO. 
MVFR ceilings will develop slightly after SFO (09-10Z) and dissipate 
to SCT before SFO does (17-18Z). Will remain patchy through the late 
morning and become fully VFR by 19Z.

Vicinity of SJC and OAK...SW winds are continuing to weaken and
will continue into the overnight hours. MVFR ceilings will impact
OAK first around 07Z Saturday followed by SJC a couple hours 
later (09Z Saturday). Winds ease overnight before increasing again
Saturday morning when the stratus begins to scatter out of their 
respective areas.

Monterey Bay Terminals...Winds continue to gradually weaken and
will continue into the overnight hours. MVFR ceilings return this
evening, impacting SNS first around 06Z and MRY by 07Z Saturday. 
Medium confidence on the timing of stratus at MRY as it may be 
intermittent at times. There also might be some light drizzle 
associated with the marine layer as it comes onshore, similar to 
this morning, but confidence is too low to include in the TAF. 

&&

.MARINE...
(Tonight through next Thursday)
Issued at 920 PM PDT Fri Jun 19 2026

Winds will increase becoming fresh to strong out of the west into
the early evening hours. Hazardous conditions for small craft are
expected across the San Francisco Bay, Suisun Bay, San Pablo Bay
and Monterey Bay. Long period southwest swell will persist into
the weekend with moderate W/SW winds across the outer waters.
Winds will briefly ease Saturday but will increase again across
the outer northern water early Sunday into the beginning of next
week.

&&

.BEACHES...
Issued at 1245 AM PDT Sat Jun 20 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 tonight. 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 9 PM Saturday to 3 AM PDT Monday for 
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Tangen
LONG TERM....Tangen
AVIATION...Malarkey
MARINE...Canepa

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Prepared by Boulder-Creek.com Weather at: Sat Jun 20 02:30:03 PDT 2026