138
FXUS66 KLOX 140623
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1123 PM PDT Sun Jul 13 2025

.SYNOPSIS...13/802 PM.

Night through morning low clouds and patchy fog will affect the
coasts and most valleys through most of this work week. High
temperatures will remain below normal through Monday except for
far interior valleys. A cooling trend will develop Tuesday and
continue through the middle of the week when valley highs are
only expected to be in the 80s.

&&

.SHORT TERM (TDY-TUE)...13/759 PM.

***UPDATE***

The marine inversion was around 1300 ft deep early this evening
and should deepen some overnight. Low clouds never really cleared
off the coast much today and were already expanding along the
coast and moving inland over much of the coastal plain. The low
clouds will push a bit further inland into the adjacent vlys
overnight. Low clouds and fog are also expected to develop over
the southern Salinas Vly in SLO County late tonight. Patchy
drizzle cannot be ruled out with the low clouds late tonight as
well. Otherwise and elsewhere, mostly clear skies will prevail
thru the night. Breezy to gusty SW to W winds, strongest over the
L.A. County mtns and Antelope Vly foothills, will slowly diminish
overnight.

The current forecast is on track in the short-term and do not
anticipate any zone updates this evening.

***From Previous Discussion***

Continued minimal day to day changes are expected through
Wednesday. A weak high pressure system of 595 to 596 dam will
remain over the region with slight changes through Monday morning,
and continue to break down over the Monday night through
Wednesday period, slowly lowering heights to 591 dam by Tuesday.
Additionally, strong onshore flow will continue with gradients
peaking during the afternoon hours both to the east (5 to 9 mb)
and to the north (4 to 6 mb).

Thanks to this strong onshore flow, night through morning low
clouds and fog will continue to make an appearance into coastal
valleys through the days, with slow to minimal clearing at the
west-facing beaches each day. An early return of marine layer
clouds will also occur as a result of the strong onshore
gradients. Additionally, with the deep marine layer and the
strong temperature inversion overtop due to high pressure, patchy
drizzle will be possible across the coasts and valleys during the
morning hours Monday and Tuesday, similar to this morning.

Max temperatures on Monday will be very similar to todays, with 70s
across the coasts (mid to upper 60s beaches) and 80s and lower
90s in the valleys. These max temps are mostly 3 to 6 degrees
below normal for this time of year. The interior areas such as
Cuyama and Antelope Valley, however, with no marine influence
will continue to see max temps from 100 to 105 each day which is 5
degrees above normal. The lower heights on Tuesday and Wednesday
(both will be very similar) will bring max temps down by 2 to 4
degrees at the coasts and 3 to 6 degrees elsewhere.

Lastly, gusty onshore winds will continue across interior areas
such as the western Antelope Valley and foothills each afternoon
and evening. These winds will be near advisory levels, but only a
few of the typical gusty locations will see gusts near 45 mph.

.LONG TERM (WED-SAT)...13/232 PM.

For the long term period at the surface, the strong onshore flow
will continue through Thursday, and may even become a mb stronger,
before starting to weaken Thursday night through Friday. As for
the upper level pattern, high pressure will linger over the Great
Basin, with a weak low pressure system near SoCal (opening the
door for some easterly flow into the region starting Thursday
afternoon).

The conditions for Thursday will be very similar to
Tuesday/Wednesday. The night through morning low clouds and fog
will continue unabated and the beaches will continue to struggle
with clearing. Max temps will continue to run 3 to 6 locally 8
degrees below normal with highs only in the 80s across the
valleys. Strong onshore flow will continue to bring gusty (likely
advisory level) winds to some of the mountains as well as the
western portions of the Antelope Valley and foothills.

Thursday afternoon/evening, both the GFS and EC deterministic
runs, as well as the majority of their ensembles, are starting to
agree that moisture between 850 and 500 mb will move into the
region from the SE and really ramp up Friday into the weekend.
The NBM has little in the way of cloud cover forecast, but would
not be surprised is skies were at least partly cloudy. As of now,
the highest probability for monsoonal thunderstorms remains the
the E and SE of our region, however, there is still a 10 to 15
percent chance for thunderstorms across the LA/Ventura interior
mountains and the Antelope Valley during the afternoon and
evening hours Thursday through Sunday.

&&

.AVIATION...14/0602Z.

At 0505Z at KLAX, the marine layer was 1300 ft deep. The top of
the inversion was at 4100 feet with a max temperature of 24 C.

High confidence in TAFs for KWJF and KPMD.

MDT confidence in remaining TAFs. Timing of flight cat changes may
be off by 90 minutes. There is a 20 percent chc of SCT conds for 1
to 2 hours in the afternoon at sites with no clearing fcst.

There is a 20% chc for cigs 002-004 at KPRB between 12Z and 16Z.

KLAX...Moderate confidence in TAF. There is a 20% chance of
clearing (or brief) from 21Z to 00Z. No significant east wind
component expected.

KBUR...Moderate confidence in 00Z TAF. Arrival of cigs tonight
may be off +/- 2 hours. There a 30 percent chc of cigs below 005.

&&

.MARINE...13/708 PM.

Through this evening, localized Small Craft Advisory (SCA) W to
NW winds may impact the waters around Point Conception south to
the Channel Islands, western portions of the Santa Barbara Channel
and nearshore from Point Mugu to Pacific Palisades.

Otherwise, relatively benign conditions are expected through
Thursday, with the exception of patchy dense fog tonight into
tomorrow morning. SCA level winds focused across the outer
waters may become more widespread Friday into the weekend.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Lund/Sirard
AVIATION...Rorke
MARINE...Black
SYNOPSIS...Black/KL/Sirard

weather.gov/losangeles

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