Mount Wilson, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

602
FXUS66 KLOX 270942
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
242 AM PDT Sun Jul 27 2025

.SYNOPSIS...27/226 AM.

An upper-level trough anchored along the West Coast will keep a
persistent onshore flow pattern in place through Tuesday. Night
through morning low clouds and fog will remain in the forecast for
most coastal and valley locations. A slow warming trend will take
shape through the week, especially outside the marine layer depth
as high pressure aloft over the southeastern United States
meanders west. Closer to the coast, onshore flow will keep the
warming trend moderated with temperatures remaining below normal
through much of the week.

&&

.SHORT TERM (TDY-TUE)...27/224 AM.

The latest water vapor imagery shows an upper-level trough
anchored over the West Coast this morning with a broad upper-level
ridge of high pressure over the southeastern United States. A few
high clouds are developing over the area this morning as a vort
max with the weak trough is moving over the region. Fog product
imagery indicates low clouds and fog well-entrenched along the
Central Coast early this morning, while an eddy circulation over
the southern California is a little slower to regenerate. With the
vorticity maximum moving over the region, drizzle cannot be ruled
out across the coastal and valley areas this morning, but if the
eddy circulation begins to push clouds back into the Southland,
this portion of the area would be in a little more favorable areas
for drizzle to develop.

Low clouds and fog will remain a staple of the forecast for the
next several nights and mornings across most coastal and valley
areas, but 500 mb heights will climb over the next several days.
This will very likely thin the marine layer depth through the
short term period. The troughto the northwest of the area will
serve to keep the marine influence and strong onshore flow in
place. A pattern reminiscent of June will set up with a strong
onshore push and a tight marine inversion developing. Clouds will
likely struggle to clear from the land mass each day, especially
along the Central Coast where the region is much closer to the
trough`s influence. EPS ensemble cloud cover means indicate
minimal clearing each day at K87Q, KVBG, and KLPC, and clouds
should be expected to hug the Central Coast each day.

Outside of the marine influence in the higher valleys, foothills,
mountains, and desert, a gradual warming trend will develop with a
few degrees of warming each day. Temperatures will inch closer to
normal by Tuesday across the interior portions of the area, but
within the marine intrusion, a cooler than normal air mass will
likely remain. The warming trend will be much more muted along the
coast and at the beaches.

A northwesterly surface gradient will keep enhanced diurnal winds
across southern Santa Barbara County for the next several nights,
but gusty Sundowner winds are not expected through the short-
term period at this time.

.LONG TERM (WED-SAT)...27/226 AM.

The northwest surface gradient will tighten a bit more on
Wednesday as a weak upper-level trough moves over central
California. A much cooler air mass to the northwest of the area
and a warmer air mass remaining over southeastern California will
likely set up a tighter northwesterly gradient across the region.
KSBA-KSMX surface pressure gradients tighten for Wednesday
evening and this could be the first evening of advisory level
Sundowner winds.

EPS ensemble members suggest some cooling taking place along the
coast and valley areas as 500 mb heights decline between Wednesday
and Thursday. Onshore flow is likely to increase across the region
and some deepening of the marine layer seems plausible between
Wednesday and Thursday.

After Thursday, 500 mb heights will start to climb again and bring
additional warming away from the coast and into the interior
portions of the area. These areas will likely pop above normal for
late week with temperatures possibly closing in on the 100 degrees
out in the Antelope Valley on Friday. Despite the rising heights,
cluster analysis reveals the persist trough remaining over the
West Coast. This will likely keep onshore flow in place and keep
night through morning low clouds and fog a staple of the forecast
for most coastal and valley areas.

&&

.AVIATION...27/0543Z.

At 0454Z at KLAX, the marine layer was around 1200 ft deep. The
top of the inversion was around 3000 feet with a max temperature
of 19 C.

High confidence in VFR TAFs for KWJF and KPMD.

Low confidence in TAF for KSBA, where there is a 40% chance for
VFR conds to prevail. If cigs arrive, minimum cig height may be
off +/- 500 feet and timing may be off by 2 hours.

Moderate confidence in remaining TAFs. High confidence in cigs
arriving at all sites, except moderate confidence for KPRB, KCMA,
and KBUR, KVNY. For the previous sites, there is a 10-20% chance
VFR conds prevail. Timing of flight cat change may be off by +/-
2 hours. Moderate confidence in minimum cig height (+/- 300
feet).

KLAX...Moderate confidence in TAF. High confidence in winds,
moderate confidence in timing of flight category changes (cigs may
arrive tonight as early as 07Z and as late as 10Z Sun) and cig
heights may be off by +/- 300 ft, but are likely to remain
between OVC010-OVC020 from 07Z-17Z. Timing of dissipation may be
off by +/- 90 minutes). No significant east wind component
expected.

KBUR...Cigs may arrive tonight as early as 09Z and as late as 13Z
Sun) and cig heights may be off by +/- 300 ft, but are likely to
remain between OVC010-OVC020. There is a 15% chance of no cigs
developing tonight.

&&

.MARINE...27/237 AM.

High confidence in unseasonably small (but choppy) seas into
Monday morning, then seas are likely to build to 6-8 feet across
the Outer Waters Monday evening through the period. Moderate
confidence in Small Craft Advisory (SCA) winds from Point Sal to
San Nicolas Island (with local SCA level gusts in the northern
Outer Waters) this afternoon and evening, becoming more likely
Monday afternoon through evening and expanding northward through
at least Thursday. The western portion of the Santa Barbara
Channel will reach SCA during the evenings though at least
Wednesday, with a moderate chance for winds to become widespread
enough to warrant Small Craft Advisories through Monday, then
higher chances Tuesday and Wednesday.

For Wednesday night, there is a a 30% chance of low- end Gales
for the waters beyond 20 miles from shore, with best chances from
around Point Conception south to San Nicolas Island.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT early this
      morning for zones 650-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to
      midnight PDT tonight for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Monday for zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 6 PM this evening to 3 AM
      PDT Monday for zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...Hall

weather.gov/losangeles

Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox