523
FXUS66 KLOX 010252
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
752 PM PDT Mon Aug 31 2026

.SYNOPSIS...31/751 PM.

Stagnant pattern through Friday, with below normal temperatures,
coastal clouds, and moderate Sundowner winds. Several potential
scenarios for the Labor Day weekend, with anything from benign
conditions possible, tropical rain, to hot offshore winds.

&&

.SHORT TERM (MON-THU)...31/748 PM.

With upper level trough across California and increasing onshore
flow, we have seen a cooling trend across most areas today, with
many areas seeing temperatures 5 to 10 degrees below normal
for this time of year. Current satellite imagery showing low
clouds off the Central Coast, and is expected to spread inland up
there, as well as portions of the LA/Ventura coast later tonight.
In addition to the lowering heights and stronger onshore flow,
there will be a weak eddy circulation each night which will likely
maintain a deeper marine layer depth around 2000 feet, with a few
areas perhaps even seeing some drizzle in the morning.

Onshore winds will remain enhanced across the interior during
the next few days, with gusts mostly in the 25 to 40 mph range.
This will be most enhanced across the Antelope Valley and adjacent
foothills, as well as the LA county mountains. In addition, there
will be weak to moderate sundowner winds across southwest
Santa Barbara county the next few nights. Tonight`s event is
trending weaker, with the 7 pm SBA-SMX gradient only at -1.8 mb
as compared to -4 mb yesterday at this time. There will be a
gradual increase in sundowner wind potential for Tuesday and
Wednesday evenings, when wind advisories may be needed.

***From previous discussion***

Multiple large troughs of low pressure will drive the weather
through the week. The core of the energy and moisture will stay
far enough to the north to not be concern with any rain or strong
winds, but it will maintain below normal temperatures. To clarify
however, with this being the hottest time of the year, below
normal temperatures does not mean it is time to dust off the
jackets. It will still feel warm, but thankfully not hot like it
was last week. Tropical moisture will stay away from the region as
well so it will also not feel as muggy as it did last week. With
ocean temperatures still in the 70s however, it will still feel
more humid than usual.

A deep marine layer (2,000+ feet) will continue through the week
as well, and should deepen a little more tomorrow as the trough
sags to the south. Would expect a spot or two to see drizzle in
the morning where the clouds develop, especially near the Central
Coast foothills. Solid night through morning low clouds are most
likely on the Central Coast, but coverage to the south should
remain spotty thanks to the warmer ocean temperatures, despite the
marine layer being just as deep. It is impossible to predict
exactly where those random spots of clouds will form.

Sundowner winds will continue each night over southwest Santa
Barbara County and flirt with an Advisory each time. Tonight looks
just under Advisory levels, while Tuesday and Wednesday night
look just over.

.LONG TERM (FRI-MON)...31/606 PM.

Little change expected on Friday compared to the first half of the
week.

All eyes remain focused on the Labor Day holiday weekend period. A
Hurricane is likely to develop by Wednesday or Thursday from the
clump of clouds currently just off the Baja coast. Once it forms,
it will likely move to the northwest through Saturday and towards
southern California. The big question is where will it head after
Saturday. Some deterministic models, like the current GFS, keeps
the storm moving northward and right through southern California
by Monday or Tuesday. Others, like the deterministic ECMWF, show
the storm turning to the west and never even sniffing California.
These are just two of many projections, but they do represent the
two extreme scenarios between a major rain and wind event and
little to nothing. Peering into the ensemble solutions, they
suggest that the heavy rain scenario is the least likely outcome
(5-10% of the 100 projections have 2+ inches of rain), but there
are a fair number of solutions showing light to moderate rain
(mostly under 1 inch) which would likely have minimal impacts.
The completely dry scenario comprises 20-30% of the solutions.
Which means in terms of rain, the most likely outcome is for some
light to moderate rain impacting the holiday weekend. As far as
timing is concerned, there is a small chance of showers starting
as early as Saturday, with also a small potential for monsoonal
thunderstorms over the mountains and deserts. From Sunday into
Monday night, rain chances are somewhat higher.

The wind story is similar, with a low but non- zero chance of
strong east to northeast winds causing fire and downed tree
concerns. With all that said, this is definitely a period to
monitor with a range of outcomes on the table. Due to the rarity
of this storm, expecting there to be a lot of uncertainty even as
we get to the weekend, but hopefully some details will come more
into focus by mid-week once the storm actually form.

&&

.AVIATION...01/0000Z.

At 2345Z at KLAX, the marine layer was 1300 feet deep. The top of
the inversion was at 2900 feet with a temperature of 22 Celsius.

High confidence on VFR conditions through Tuesday at KWJF KPMD.

High confidence in IFR/MVFR conditions tonight through Tuesday at
KPRB KSMX KSBP. Moderate confidence for KLAX KSMO KLGB, and low
confidence for KOXR KCMA KSBA KBUR KVNY.

KLAX...High confidence in VFR conditions to follow through at
least 06Z. Moderate confidence of MVFR cigs between 07z and 18z.
High confidence in an east winds staying under 8 knots.

KBUR...High confidence in VFR conditions through at least 08Z.
There is a 20% chance of 1-3 hours of MVFR ceilings between 10Z
and 17Z, with very low confidence on timing.

&&

.MARINE...31/142 PM.

High confidence that Small Craft Advisory (SCA) winds and short
period seas will be most common from Point Sal to San Nicolas
Island through the majority of the week. The western Santa Barbara
Channel will be flirting with SCA each evening. The nearshore
Central Coast waters will likely stay under SCA through Tuesday,
with a window of low-end SCA Wednesday and Thursday.

&&

.BEACHES...31/749 PM.

There is growing confidence for significant impacts at the coast
this Labor Day weekend. Unless the storm takes a full left turn
after Saturday, the south-southeast swell will be pumping through
the weekend into Tuesday, especially considering the swells from
the current Hurricane Karina are also still around. The most
likely scenario would result in high surf advisories for south
facing beaches during a busy holiday weekend (especially Sunday
into Monday night) with very strong rip currents. In addition,
evening high tides are also expected to be 6.5 to 6.8 feet by
Sunday evening, and around 7 feet by Monday evening. As a result,
there is an increasing chance of at least minor coastal flooding
of low-lying areas and beach erosion near times of high tides each
evening. If peak surf happens to coincide with times of high
tide, there is the potential for moderate coastal flooding/beach
erosion which could require coastal flood advisories. At this
time, the highest and most energetic swell energy will likely come
from a more southeasterly direction. A few areas that could be
especially susceptible to southeasterly swell include Catalina
Island (including Avalon), Long Beach to Cabrillo Beach, Malibu
and Point Mugu. If the storm gets closer to the coast, those
coastal impacts will be amplified.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 2 AM PDT Tuesday for
      zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 6 AM PDT Wednesday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/RK
AVIATION...Gomberg
MARINE...RK
BEACHES...Gomberg/RK
SYNOPSIS...RK

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office