Area Forecast Discussion
Issued by NWS Los Angeles, CA

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907
FXUS66 KLOX 050659
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1159 PM PDT Sat Oct 4 2025

.SYNOPSIS...04/535 PM.

A broad trough of low pressure over the West will keep cooler
than normal conditions in place through at least Friday. Breezy
northerly winds will continue across some areas into Sunday. A
warming trend is possible toward the end of next week with a
possibility of monsoonal moisture returning to the region for
next weekend.

&&

.SHORT TERM (SAT-TUE)...04/807 PM.

Broad upper-level troughing remains in place over much of the
Western States this evening. The latest water vapor imagery shows
a mostly dry cold front falling apart over northern California.
The boundary will mainly serve to deepen the marine layer depth
over the coming days and to reinforce the northerly surface
gradient this evening across the region. Mostly breezy to locally
windy northerly winds are expected tonight and into Sunday
morning across southern Santa Barbara County and through the
Interstate 5 Corridor tonight, but there is a moderate chance that
gusty Sundowner winds could reach advisory strength across the
southwestern portion of Santa Barbara County.

There is a fairly large spread with what will happen in regards
to the marine layer low cloud field overnight. The latest NAM-WRF
solutions suggest an eddy circulation developing overnight tonight
and into Sunday morning. NAM-WRF boundary layer and 975 mb
relative humidity values are indicative of low clouds developing
overnight and into early Sunday morning, but the latest EPS cloud
cover means favor less clouds at coastal terminals, such as KLAX,
KOXR, and KSMX. High-resolution multi-model ensemble members hint
at some clouds developing, consistent with an eddy circulation.
The marine layer cloudiness was expanded somewhat over the
previous forecast to introduce a bit more cloud coverage, but
coverage will likely remain confined to the Los Angeles County
coastal plain and along the Central Coast. Clouds cannot totally
be ruled out for the Ventura County coast, but the data favors
less cloudiness.

With broad troughing in place, temperatures should remain on the
cool side of normal through the period and likely into late next
week. A few tweaks will be made to overnight low temperatures, but
temperatures look agreeable at this time.

***From Previous Discussion***

After today`s expected warm up, temperature trends are expected
to be pretty flat or slightly cooler through Tuesday as there`s
very little change in the upper level pattern and onshore flow
remains on the lighter side but slowly increasing each day. Do
expect to see a more traditional marine layer returning by Sunday
or Monday. Forecast soundings show a developing marine layer
Sunday at around 1500 feet and deepening to 2000-2500 feet Monday
and Tuesday. Assuming the marine layer does re-establish overnight
lows near the coast south of Pt Conception will likely increase
as SST`s are in the mid to upper 60s. Opted to go a little above
the NBM min temps in those areas.

.LONG TERM (WED-SAT)...04/1209 PM.

Very little change in the pattern is expected Wednesday with
temperatures and sky conditions very similar to Tuesday. By
Thursday and Friday, however, there are an increasing number of
model solutions that favor a warming trend that could lead to
valley and desert highs getting back up into the upper 80s to mid
90s. This is a result of the upper low finally moving east as high
pressure begins to build north from the desert southwest.

Friday and Saturday may be interesting as there are some model
solutions indicating increasing moisture from the next tropical
system moving off the coast of Mexico. It`s a tricky pattern for
sure as there is also a pretty significant upper level low
dropping down the West coast at the same time. While there are
still a wide range of outcomes, less than 10% of the solutions are
indicating any rain chances locally, with most of the solutions
either keeping the storm moving west over the Pacific or getting
shoved east before it crosses into the US.

&&

.AVIATION...05/0657Z.

At 0515Z at KLAX, the marine layer was 500 ft deep. The top of
the inversion was at 1000 ft with a temperature of 19 C.

Good confidence in TAFs for KSBA, KOXR, KCMA, KBUR, KVNY, KPMD and
KWJF.

Moderate confidence in TAFs for KSMX and KSBP where flight cat
changes could be off by +/- 90 minutes.

Low confidence in TAFs for KSMO, KLAX and KLGB with a 40 percent
chc of IFR conds 12Z-16Z (KSMO) and a 40 percent chc of no low
clouds (KLAX and KLGB).

KLAX...Low confidence in TAF with a 40 percent chc of no clouds.
Good confidence in TAF after 17Z. Good confidence that any east
wind component will be under 6 kt.

KBUR...High confidence in CAVU TAF.

&&

.MARINE...04/732 PM.

High confidence in Small Craft Advisory (SCA) level winds across
the outer waters and nearshore waters along the Central Coast
through early Sunday morning. Seas will remain choppy and
hazardous for small craft through tonight. Thereafter, conditions
are likely to remain below SCA criteria through mid-week.

For the inner waters south of Point Conception, SCA level winds
& choppy seas are expected across the Santa Barbara Channel
through late this evening. Thereafter, conditions generally look
to remain below SCA criteria through mid-week.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 645-650-670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Sunday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall/MW
AVIATION...Rorke
MARINE...Black/Ciliberti
SYNOPSIS...Hall

weather.gov/losangeles

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