Mount Hermon, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

797
FXUS66 KMTR 150456
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
956 PM PDT Sat Jun 14 2025

...New AVIATION...

.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.

&&

.UPDATE...
Issued at 837 PM PDT Sat Jun 14 2025

Broadly speaking, the forecast remains on track this evening. In
the short term, the biggest question mark is how the marine layer
stratus will develop overnight. The stratus has pulled well off
the coast. This means new clouds will have to reform within the
marine layer, rather than roll-in as we typically see this time
of year. As a result, the confidence in the cloud cover forecast
is fairly low, even over the next 6-12 hours. Most model guidance
brings stratus back to the coast with pockets of overcast skies
along the adjacent valleys. These models are not initializing the
current clear skies well, however, and there will likely be less
cloud coverage, or at least a shorter duration.

&&

.SHORT TERM...
(This evening through Sunday)
Issued at 115 PM PDT Sat Jun 14 2025

Quiet conditions persist as a trough pattern set up off the West
Coast provides a deep onshore flow regime. This will keep temps
around seasonal normals - slightly below normal along the coast.
Otherwise, dry conditions continue at higher elevations
(generally above about 2,000 feet) where humidity recovery is poor
and grasses are very dry.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 115 PM PDT Sat Jun 14 2025

Out persistent trough pattern eventually gets kicked out by a
progressive shortwave trough moving into the West Coast. Not much
worth noting regarding our weather in this case besides the
potential for some drizzle along coastal areas early next week.
Behind the shortwave, we do see a subtle warm up on tap through
Wednesday, but again nothing worth getting bent out of shape for.
We`ll basically see high temps around normal or a few degrees
above. The main hazard over the next week will be dry conditions
inland leading to elevated grass fire danger, especially above
2,000 feet where humidity recovery is poor.

&&

.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...
(Tonight through next Friday)
Issued at 837 PM PDT Sat Jun 14 2025

The gradient between subtropical high pressure in the East
Pacific and lower pressure over the western US will continue to
support a fresh to strong NW breeze through mid-week with moderate
seas. As the gradient tightens late week, winds will increase to a
near gale force NW breeze, causing rough seas to build.

&&

.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 until 9 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Reyes to
     Pigeon Pt 0-10 nm.

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

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

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Flynn
MARINE...Flynn

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