071
FXUS66 KMTR 091203
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
503 AM PDT Mon Jun 9 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 110 AM PDT Mon Jun 9 2025

Remarkably stable weather pattern this week with temperatures
generally near the seasonal average, marine layer clouds each night
and morning, and breezy onshore winds each afternoon and evening.

&&

.SHORT TERM...
(Today and tonight)
Issued at 110 AM PDT Mon Jun 9 2025

Upper level ridging across the Pacific Northwest is just beginning
to erode, with a cutoff low that had been meandering off California
now basically absorbed into the synoptic-scale flow across the
western United States. The Bodega Bay and Point Sur profilers have
not shown much change in the marine layer depth from yesterday,
leading to high confidence that stratus will expand quite far inland
this morning, as it has for the last couple of days, with patchy fog
and drizzle possible in coastal and favored upslope areas. High
temperatures remain in the upper 70s to middle 80s inland, with the
warmest spots reaching temperatures near 100, while the coastal
regions continue to be cool with highs in the upper 50s to middle
60s, barring warmer spots near Santa Cruz and the Big Sur coast
where temperatures reach the middle 70s. Finally, breezy and gusty
onshore winds will develop during the afternoon and evening, with
the strongest gusts of 20 to 30 mph through the gaps and passes,
along the coastal jets, and within the Salinas Valley.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 110 AM PDT Mon Jun 9 2025

The upper level ridge continues to erode through the next couple
days, with a trough coming into the region later this week.
Temperatures through the week remain remarkably stable. Perhaps
Friday and Saturday will see temperatures a few degrees cooler than
those from earlier in the week, as the trough reinforces the onshore
flow and deepens the marine layer, but temperatures will generally
remain near or slightly below seasonal averages. Speaking of the
marine layer, the marine layer stratus should build inland each
night and morning before dissipating through the afternoon, while
winds will remain breezy and gusty each afternoon and evening.

&&

.AVIATION...
(12Z TAFS)
Issued at 438 AM PDT Mon Jun 9 2025

Enhanced IR satellite imagery indicates an obviously deeper marine
layer this morning. As the morning weather balloon ascends, the
depth is revealed to be around 2,200 feet. This depth is causing
widespread stratus across the Bay Area and Central Coast. The
cloud layer is also relatively thick, with cloud bases around 500
feet and tops over 2,000 feet. This cloud layer depth will cause
a later erosion time compared to previous days, with coastal sites
likely keeping ceilings all day.

Vicinity of SFO...While surface winds are westerly, boundary layer
averaged winds are more northerly. This means the clouds are
streaming over the Bay rather than over the coastal mountains,
and SFO won`t enjoy the donut hole of clear skies seen over much
of the weekend. IFR ceilings are expected through the early
morning with improvement this afternoon as a moderate to strong
WNW breeze kicks in. Low clouds will almost certainly return this
evening. Note: the SJC ASOS is down and our technicians will
troubleshoot the issue this morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR ceilings approaching airport
minimums are observed this morning with no signs of improvement
until around 17Z. With the ceilings so low, there is also around a
25% for the visibility to drop below 1 mile over the next 2 or 3
hours. Guidance is split on whether ceilings will break at MRY
this afternoon, but persistence has encouraged me to take the
pessimistic approach with IFR impacts throughout the TAF period.
SNS has a better chance of clearing before stratus returns this
evening.

&&

.MARINE...
(Today through Saturday)
Issued at 438 AM PDT Mon Jun 9 2025

A moderate to fresh NW breeze will persist across the coastal
waters through mid week. A low amplitude, long period
southwesterly swell arrives Monday, bringing enhanced currents
and causing waves to break in deeper water. A tighter pressure
gradient will bring strong NW winds and rough seas through the
second half of the week.

&&

.BEACHES...
Issued at 117 PM PDT Sun Jun 8 2025

A long period southerly swell will enter the waters Monday into
Tuesday bringing a higher risk for rip current along beaches.
Breaking waves about 5 to 7 feet, but strong currents and sneaker
waves will be the bigger hazard. Use caution near the water and
never turn your back on the ocean.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Pigeon Pt to Pt Pinos 0-10 nm-SF Bay N of Bay
     Bridge.

     Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for Pigeon Pt
     to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-SF Bay N
     of Bay Bridge.

     Small Craft Advisory from 3 PM this afternoon to 3 AM PDT
     Tuesday for Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 9 PM PDT
     Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Flynn
MARINE...Flynn

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