646
FXUS66 KLOX 290259
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
759 PM PDT Sat Jun 28 2025

.SYNOPSIS...28/211 PM.

Dry conditions and near-normal temperatures will persist for the
remainder of this weekend and through early next week. A slight
cool-down is expected for the middle of next week, though dry
conditions will persist. Expect night through morning low clouds
and patchy fog over the coasts and some coastal valleys.

&&

.SHORT TERM (SAT-TUE)...28/756 PM.

***UPDATE***

The forecast is in good shape and only minor changes to
temperatures and marine layer coverage and timing were made.

The marine layer cleared from most of the beaches today, save for
the Central Coast. Low clouds will return tonight, with slightly
less extent into the valleys of LA County possible. Tweaked the
sky coverage to reflect this, as well as brought low clouds into
the Santa Barbara south coast and Ventura County coast earlier and
delayed the return to the LA County coast until later tonight.

High temperatures today generally ranged from the mid 60s to low
70s at the beaches, with the exception of the beaches along the
Central Coast, which topped out in the mid 50s to low 60s thanks
in part to the aforementioned stubborn marine layer. Many of the
valleys were solidly in the 80s and 90s, with the western San
Fernando Valley being the warmest as temperatures in the mid to
upper 90s were widespread. Temps in the mid to upper 90s were
also scattered across the Santa Clarita, Eastern San Gabriel, and
Cuyama valleys. The Antelope Valley and surrounding foothills
reached the low to mid 90s, and seasonal gusty SW winds
(generally 25 to 35 mph) have been observed this afternoon and
evening and will taper off relatively soon. Another round of
winds of slightly lower magnitude is forecast for tomorrow
afternoon and evening.

Tomorrow will look much like today in the way of high temps and
most areas will be within a few degrees of normal. However, high
temps were increased slightly across the LA and Ventura County
valleys. The Central Coast will remain a few degrees below
normal, while the highs in the valleys will remain around 5
degrees above normal. Moderate onshore flow will continue tomorrow
to the east and north, although slightly less in terms of
magnitude. Overall fairly quiet weather will continue.

***From Previous Discussion***

Quiescent weather conditions will prevail throughout the entirety
of the forecast period.

Modest onshore pressure gradients are in place, generally ranging
from 2 to 4 mb for standard location pairings (e.g., LAX-DAG and
LAX-BFL). And with a midlevel ridge extending west from a 592-dam
500-mb high centered south of the Four Corners, coastal stratus
and fog have mostly dissipated as of early this afternoon. Under
sunny skies, temperatures are seasonably warm in most areas away
from the coast, breaching the 90-degree mark in some of the
typical warm spots across the interior such as in the western San
Fernando Valley, Cuyama Valley, and Antelope Valley. Another
couple degrees of warming are anticipated this afternoon. The
modest onshore gradients are keeping wind gusts well below
advisory thresholds, though a few 20-30 mph gusts continue below
favored canyons and passes in the interior.

For the rest of the weekend and into early next week, day-to-day
variability in sensible weather conditions will be minimal, as
the pressure pattern at the surface and aloft only very slowly
evolve. A diffuse upper low, currently located a few hundred
miles southwest of the Channel Islands, will slowly edge
northeastward toward the Central Coast before stalling off the
SLO County coast early next week. The low will deepen along its
trajectory, while the aforementioned upper ridge downstream builds
and amplifies. This amplifying and sharpening trough-ridge
pattern across the Pacific coast will tend to facilitate a
gradual increase in onshore gradients -- perhaps a 0.5-1 mb
increase from day to day. While this should have a tendency of
driving the marine layer -- and its related cooling, cloudiness,
and fog effects -- farther inland from day to day, the building
ridge to the east of the region should offset significant
deepening of the marine layer, at least before Monday night. In
summary, conditions should largely remain similar from day to day.

However, by Monday night and Tuesday, cyclonic vorticity
advection and related differential advection preceding the upper
low will overwhelm height fields over the local area to facilitate
more pronounced deepening and inland spread of the marine layer.
Marine clouds and fog should be slower to clear over coastal areas
and the coastal valleys on Tuesday, and will likely extend farther
inland across most of the coastal valleys by early Tuesday
morning before more slowly dissipating. While seemingly unlikely,
a few patches of very light drizzle could be mixed in with the
deeper marine layer Monday night and/or Tuesday morning,
especially if a mesoscale eddy were to focus onshore flow
somewhere between Santa Monica and Long Beach, and also along the
Central Coast. Otherwise high temperatures Tuesday are expected to
drop by a degree or so from preceding days, in response to the
onset of subtle midlevel height falls, though still reaching the
80s and 90s in most places away from the coast.

Also of note, the increased onshore pressure gradients early next
week will facilitate a small uptick in southwest to west wind
gusts around interior higher terrain. Local gusts to 40 mph are a
possibility by Monday and Tuesday, however, any advisory-level
winds are presently forecast to be too brief and/or spotty to
warrant wind headlines -- i.e., less than 20 percent chance.

.LONG TERM (WED-SAT)...28/211 PM.

Moderately enhanced onshore pressure gradients (8-9 mb LAX-DAG)
will persist through much of next week, while the aforementioned
upper low eventually picks up momentum and accelerates eastward
Wednesday through the end of the week. After the marine layer more
robustly establishes over the area early next week, the cold pool
aloft attendant to the upper low may scour out the inversion
surmounting the marine layer on Wednesday and Thursday, muting
stratus/fog development and/or fostering early-day onset of its
dissipation. However, the cooler air aloft will subdue the diurnal
heating cycle, with Wednesday/Thursday high temperatures expected
to remain below 90 degrees in most areas except the Antelope
Valley.

Heights look to rebound by the end of next week into next weekend,
which should gradually reinforce the marine layer along with
accompanying night through morning low clouds and fog near the
coast. A very slow warming trend is anticipated mainly for
locations away from the coast. However, reinforcing upper
vorticity centers north of the forecast area should have the
peripheral effect of limiting midlevel height rises. This will
tend to mute the overall strength of warming and marine-layer
reinforcement from day to day.

Breezy winds with local gusts of 30-40 mph will persist over the
mountainous interior in enhanced onshore flow facilitated by the
moderate pressure gradients. While a few gusts could exceed 45
mph, confidence in any more than brief/spotty advisory-level gusts
is low, and the probability for wind headlines to be issued is
currently under 20 percent.

In summary, little overall change in sensible weather conditions
is expected through next weekend across the area. It will remain
dry through the period, and the quiescent weather conditions will
continue through the entirety of the long-term forecast period.

&&

.AVIATION...28/2346Z.

At 22Z at KLAX, the marine layer was 0800 ft deep. The top of the
inversion was at 2000 ft with a temperature of 26 Celsius.

High confidence in VFR conditions with afternoon/evening gusty
southwest winds at KPRB, KWJF and KPMD.

Ceiling chances at the other sites: KSBP (70%) KSMX (100%) KSBA
(80%) KOXR (90%) KCMA (70%) KSMO (90%) KLAX (90%) KLGB (80%) KBUR
(30%) KVNY (20%). Moderate confidence of ceilings slightly lower
tonight compared to last night. High risk of LIFR conditions at
KSBP KSMX KSBA, moderate risk at KOXR KCMA.

KLAX...Moderate confidence in VFR conditions persisting through
the 04Z rush. 90% chance of OVC006-012 ceilings forming, as early
as 03Z and as late as 08Z. 10% chance of brief OVC003 10-15Z.
High confidence in any east wind component staying under 08 knots.

KBUR...30% chance of BKN003-006 ceilings 10-15Z Sunday.
Otherwise, VFR conditions will prevail with seasonable onshore
flow.

&&

.MARINE...28/613 PM.

For the Outer Waters, moderate to high confidence in current
forecast. Through Tuesday, high confidence in winds and seas
remaining below Small Craft Advisory levels and much quieter than
usual. For Wednesday through Thursday, there is a 30-50% chance
of both SCA level winds and seas.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Through Wednesday, winds and seas
will remain below SCA levels and remain much quieter than usual.
On Thursday, there is a 20-30% chance of SCA level seas.

For the Inner Waters south of Point Conception, high confidence in
current forecast. Today through Thursday, winds and seas will
remain well below SCA levels.

&&

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

&&

$$

PUBLIC...Cohen/Lewis
AVIATION...Kittell
MARINE...RAT/RK
SYNOPSIS...Cohen

weather.gov/losangeles

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