Bethel Island, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

813
FXUS66 KMTR 151028
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
328 AM PDT Sun Jun 15 2025

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

.SYNOPSIS...
Issued at 115 PM PDT Sat Jun 14 2025

Cool and calm conditions prevail. Warm temperatures inland, but
still near seasonal normals. Slight warming trend inland mid next
week. Dry conditions persist across high terrain, leading to
elevated grass fire danger.

&&

.SHORT TERM...
(Today and tonight)
Issued at 327 AM PDT Sun Jun 15 2025

No significant change to the forecast, with persistence carrying
through at least today into early Monday before a subtle pattern
change takes shape in the form of a slightly deepening trough
approaching from the west Monday afternoon. Weak shortwave H50 rises
today out ahead of the approaching trough will result in another
respite of June Gloom for most locations with patchy low stratus
lingering across the San Mateo coastline into the Bay area this
afternoon. With the steadier, increasing fetch of onshore flow
getting closer late tonight we`ll see more widespread marine layer
stratus develop by early Monday morning.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 327 AM PDT Sun Jun 15 2025

The aforementioned subtle pattern change will see shortwave ridging
on the backside of the weak trough passing across our area Monday,
helping to lift temperatures on Tuesday and Wednesday slightly above
normal. The brief warm up will through the middle of the week will
see temperatures return to mostly normal for the end of the week as
another trough is positioned to our west. A secondary, deeper and
sharper trough next weekend may bring gusty winds and a potential
increase in fire (grassland) weather concerns through the remainder
of the extended forecast.

&&

.AVIATION...
(06Z TAFS)
Issued at 954 PM PDT Sat Jun 14 2025

VFR conditions have persisted through the evening, though patches of
stratus are starting to form along the coast. In the big picture,
the region and coastal waters are much more clear than you would
expect under onshore flow in June. While the marine layer is in
place, its mostly cloud free due to low moisture in the atmosphere.
This makes the aviation forecast tricky as we must wait for stratus
pockets to form, rather than roll in off the coast. Most model
guidance is insisting that will happen, but the exact location and
duration is hard to pin down. Some terminals will likely stay VFR
through the night, and those that do develop ceilings will likely
have a shorter duration than normal.

Vicinity of SFO...Moderate onshore winds are easing overnight. The
chance for ceilings at SFO remains similar to a coin-flip, though
the fact that the area is still mostly clear certainly makes it seem
more optimistic that VFR conditions could last through the morning.
The 06Z TAFs are keeping MVFR ceilings at OAK however, as the HREF
remains more aggressive in the East Bay. If any ceilings do form they
will clear quickly Sunday morning before moderate onshore winds
develop Sunday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Low clouds have started to form along the
Monterey Peninsula, and will likely reach the terminal shortly with
NW winds helping to advect and grow the small cloud deck. SNS will
also likely develop ceilings, though the duration will be limited to
a few hours around sunrise. The ceiling height should settle in
the IFR category, as the marine layer is more shallow over the
southern terminals due to higher pressure.

&&

.MARINE...
(Today through Friday)
Issued at 327 AM PDT Sun Jun 15 2025

Surface high pressure will support a fresh to strong northwest
breeze occasionally approaching gale force across the coastal
waters with moderate seas through mid-week. An eastward passing
upper level trough combining with a strengthening onshore pressure
gradient will result in gusty onshore winds across the bays Monday
afternoon and evening.

&&

.FIRE WEATHER...
Issued at 556 PM PDT Sat Jun 14 2025

No real notable changes to the ongoing forecast fire weather wise.
Still highlighting elevated fire weather conditions across the
interior Central Coast. While not in our forecast area, a decent
veg fire developed and spread quickly to over 1k acres in SLO.
This could have easily happened in San Benito or Monterey
counties.

Observations over the last 24 hour and predicted weather continue
to show marine layer influence keeping fire weather conditions in
check for lower elevations and coastal areas. However, about
roughly 2k feet and farther inland conditions remain mild and dry
both day and night. On top of that is onshore flow leading to
breezy conditions each afternoon. Some of the winds are being
enhanced by topography leading to gustier flow in the valleys,
gaps, passes with 20-35 mph gusts.

Simply put, if you`re recreating outdoors, be one less spark in
these elevated fire weather conditions.

MM

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM to 9 PM PDT Monday 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 Monday for Mry Bay.

     Small Craft Advisory until 3 PM PDT Monday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 9 PM PDT Monday
     for Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Canepa
MARINE...Canepa

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