Altadena, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

075
FXUS66 KMTR 261748
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1048 AM PDT Thu Jun 26 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 902 AM PDT Thu Jun 26 2025

Seasonal temperatures with night and morning stratus will continue
into next week.

&&

.UPDATE...
Issued at 902 AM PDT Thu Jun 26 2025

Much less stratus coverage this morning with the marine layer
around 1100 feet and mainly impacting SF Bay and Monterey Bay
region with lots more sunshine for the North Bay this morning.
Local northeast winds aloft are coming off Mt Saint Helena and
ushering in drier air and sunny skies across the North Bay this
morning. Low clouds in the Berkeley hills should erode shortly
while the Salinas Valley clouds are starting to slowly mix out.

In general expect a few degrees of a warming trend for inland
areas today with some earlier sunshine even with continued onshore
wind pattern.

Expect the marine layer to continue to compress to less than 1000
feet into Friday. This in combination with building ridge should
lead to inland highs back into the lower to mid 90s for places
like Santa Rosa, Concord and Livermore just in time for a nice
summer weekend. Models suggest a decent cool down by Sunday as a
weak trough off the coast induces a cool southwesterly onshore
push for places like Santa Rosa and Napa. Next weeks forecast will
revolve around that upper low. Will check over the 12z models and
focus on the extended for the afternoon packages.

&&

.SHORT TERM...
(Today and tonight)
Issued at 227 AM PDT Thu Jun 26 2025

Another June day on tap with temperatures generally near seasonal
normals. The marine layer is currently being observed at 1,100
feet on the Fort Ord profiler with satellite showing stratus along
the Pacific Coast, through the Golden Gate Gap, and down the
Northern Salinas Valley. Expect stratus to retreat towards the
coast by late-morning with some mist/drizzle possible until then.
Your weather nugget of the day is that the 00Z 06/26/2025 weather
balloon recorded a precipitable water value of 0.42 inches, that
is below the 10th percentile (0.48 inches) for the day.

A Coastal Flood Advisory (the last one of this astronomical high
tide sequence) is in effect from 11PM Thursday through 2AM Friday
for Bayshore locations of the San Francisco Bay and San Pablo Bay
for minor coastal flooding during nocturnal high tide. Known impacts
occur in Bayside Marin County where coastal locations next to
Richardson Bay such as Sausalito, Tam Valley, Manzanita, the
Sausalito-Mill Valley Bike Path, and the Manzanita Park N Ride
experience localized flooding. As always, do not drive around
barricades or through water of unknown depth.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 227 AM PDT Thu Jun 26 2025

Typical June Gloom/No Sky July long term forecast on tap with one
caveat...

Global ensemble clusters are in agreement of an upper-level
shortwave trough making its way into our area late weekend into
early next week. All three deterministic models (Canadian, ECMWF,
and GFS) show a negatively-tilted 582 dam upper-level cutoff low off
our coast at 12Z (5AM) Monday. While that may sound exciting, as of
now there`s no mentionable precipitation or thunderstorm chances.
Precipitable water values are forecast to increase, but point model
soundings show 0 CAPE, so instability seems to be the missing
ingredient from the three ingredients method (lift, instability,
moisture). As is typical with cutoff lows, they are notoriously
difficult to forecast due to their lack of jet stream support. Add
in an active Eastern Pacific Basin and the forecast becomes even
more complex - which is what we are dealing with!

&&

.AVIATION...
(18Z TAFS)
Issued at 1047 AM PDT Thu Jun 26 2025

MVFR currently at MRY, OAK and SFO with clearing anticipated by 19Z-
1930Z. Low ceilings (LIFR/IFR) at HAF that may linger through much
of the day. Winds increase this afternoon with gusty conditions at
most terminals, easing overnight and into Friday morning. However,
low clouds (IFR/MVFR with the greatest potential for LIFR at MRY and
SNS) are forecast to return to the Bay Area and Monterey Bay
terminals by late evening or early Friday morning. Any low ceilings
that do develop will clear out late Friday morning with increasing
onshore winds.

Vicinity of SFO...MVFR returning to VFR by late morning. Onshore
winds increase once again this afternoon with gusts currently
forecast to be 31 kt. Winds ease after sunset with a return to
IFR/MVFR ceilings. Any low clouds that do develop will
scatter out by 18Z Friday. Moderate confidence.

SFO Bridge Approach....The San Mateo Bridge Approach will likely
remain clear though the TAF period; however, low stratus clouds
between OAK, SFO, and northward through the Golden Gate Bridge are
forecast to return late this evening and into Friday morning.

Monterey Bay Terminals...MVFR at MRY returning to VFR by late
morning. Onshore winds increase this afternoon before easing late in
the evening. IFR/MVFR ceilings likely to return late this evening
and potentially lowering to LIFR early Friday morning. High
confidence.

&&

.MARINE...
(Today through Tuesday)
Issued at 1047 AM PDT Thu Jun 26 2025

Fresh to strong northwesterly breezes with near-gale force gusts
will continue through Friday. Gale force gusts can be expected
near the coastal jet regions of Point Reyes and Point Sur this
afternoon and evening. Moderate to rough seas will also continue
through Friday, with northwesterly winds easing over the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 11 PM this evening to 2 AM PDT
     Friday for CAZ006-506-508.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

     Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
     Reyes 0-10 nm.

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

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

     Gale Warning from 3 PM this afternoon to 3 AM PDT Friday for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT Friday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

UPDATE.......RWW
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...RGass
MARINE...RGass

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