379
FXUS66 KLOX 020519
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1019 PM PDT Tue Sep 1 2026

.SYNOPSIS...01/750 PM.

Stagnant pattern through Friday, with below normal temperatures,
patchy marine layer clouds, and moderate Sundowner winds. Several
potential scenarios for the Labor Day weekend, with anything from
benign conditions, tropical rain, or even hot offshore winds.

&&

.SHORT TERM (TUE-FRI)...01/818 PM.

***UPDATE***

Today made out to be a sunny day once the morning patchy marine
layer clouds burned off. High temperatures were mainly in the 70s
and 80s across the region, with 60s the Central Coast. Typical
sub-advisory gusty late afternoon/evening onshore winds have been
affecting the Antelope Valley. Meanwhile, Sundowner winds have
started to pick up this evening across the Santa Barbara Southwest
Coast, where a Wind Advisory is in effect until 6am PDT Wednesday
morning.

Current satellite imagery shows patchy marine layer clouds forming
along the Central Coast, but not much else at this time. Expecting
clouds to spread throughout the Central Coast overnight, with less
confidence for south of Point Conception. Onshore surface
pressure gradients are a little bit weaker tonight compared to
yesterday and no clouds are currently in sight, so if clouds do
form, it would either be randomly on sight, or pushed in much
later tonight, and for a few hours into the morning.

Similar conditions are expected tomorrow with little change in the
upper level pattern and a slight decrease in onshore winds from
the N/S gradient.

***From Previous Discussion***

Overall, 12Z models in good synoptic agreement through the short
term period. At upper levels, a trough will remain over the West
Coast, varying in strength from day-to-day. At the surface,
moderate onshore flow will continue to the east with some offshore
flow from the north.

With this pattern, relatively benign weather is expected for the
area. Main concern will be winds, specifically Sundowner winds,
across southern Santa Barbara county. High resolution models
indicate stronger SBA-SMX gradients tonight which will produce
stronger winds across the western Santa Ynez Range and will likely
hit advisory-levels overnight. So, have issued a WIND ADVISORY for
the western Santa Ynez Range and adjacent coastal strip through
600 AM Wednesday morning. Based on SBA-BFL gradient, there may be
some gusty winds across the eastern Santa Ynez Range (Montecito
area), but advisory-level winds are expected at this time. For
Wednesday night, models indicate even a bit strong northerly flow,
so advisory-level winds will likely continue across southern
Santa Barbara county.

As for clouds, there will be some marine layer stratus/fog each
night and morning across the coastal plain and some coastal
valleys, due to the onshore flow and potential eddy circulations.
However, confidence in areal coverage each night remains low.
Other than any stratus/fog, skies should remain mostly clear
through Friday.

Finally for temperatures, there will only be minor day-to-day
changes, based on the whims of the marine influence and changes in
H5 heights. For most areas, high temperatures will remain about
2-6 degrees below seasonal normals.

.LONG TERM (SAT-TUE)...01/932 PM.

For the long term period, an upper low is forecast to wobble over
and around the Pacific Northwest through the Labor Day weekend.
Models vary on the exact path of the wobble, but cyclonic flow
aloft will remain over the area through early next week. At the
surface, focus remains on current Tropical Storm Marie. While some
more models/ensemble members are starting to come into agreement
with a more northwestward track away from SW California, still
quite a bit of uncertainty in exact details for impacts across the
region this weekend.

Currently, Marie is located between 15N and 20 N, and around 110W.
The latest forecast from the National Hurricane Center has Marie
intensifying to hurricane strength early this morning, following a
track to the northwest through the Labor Day weekend. The chances
of Marie directly hitting Southern California as a hurricane or
tropical storm remain VERY LOW (with only a few ensemble members
from the models indicate any track close to Southern California).

However, despite the HIGH likelihood of Marie maintaining a west
to northwest track away from the West Coast, there still be some
noticeable impacts for the area from this storm. With the upper
level pattern, moisture from Marie will be advected over the area
during the Labor Day weekend, but the amount of moisture will be
greatly impacted by the exact track of the hurricane. At this
time, there is a 50-60% chance of widespread light rainfall
(amounts 0.10-0.50 inches) Sunday through Tuesday and about a
10-15% chance of heavy rainfall and thunderstorms. As for winds,
there will be about a 10-15% chance of moderate to strong easterly
winds ahead of any rainfall, which could produce some fire
weather concerns. Finally, there is high confidence in significant
coastal risks which are detailed in the Marine and Beaches
segments of this discussion.

Needless to say, the weather for the upcoming Labor Day weekend
may by highly dynamic. A minor change in the track of Marie could
result in significant changes to the current forecast. So, given
the uncertainty with this pattern, stay tuned and monitor the
latest forecasts.

&&

.AVIATION...02/0519Z.

At 0439Z at KLAX, the marine layer was 1100 feet deep with an
inversion at 2500 feet and 21 degrees C.

High confidence on VFR TAFs at KPRB, KSBA, KOXR, KCMA, KBUR, KVNY
KWJF, and KPMD. 10% chance for very brief MVFR cigs at coastal
sites sometime between 12Z-17Z.

Low to moderate confidence in SCT to BKN MVFR conds for remaining
sites, with best chance of cigs at KSMX/KSBP. Small chance for
IFR conds at those sites. 50% chance for VFR conds to prevail at
KLGB, and 30% chance for very brief MVFR cigs at coastal sites
sometime between 12Z-17Z at KLAX/KSMO.

KLAX...Moderate confidence in TAF. There is a 30% chance for brief
BKN012-015 cigs developing sometime from 12Z-17Z. No significant
east wind component expected.

KBUR...High confidence in TAF otherwise, with a 10% chance for
brief BKN0010-15 cigs from 12-16Z.

&&

.MARINE...01/900 PM.

Moderate to high confidence for Small Craft Advisory (SCA) level
winds and short-period seas across the southern Outer Waters
today through Friday, with a 20-40% chance of SCA level winds
extending to the inner and outer waters north of Point Sal
(greatest chance in the afternoon/evenings). For Saturday, there
is a 30-40% chance of SCA level wind across all of the Outer
Waters.

SCA level winds appear likely across the Santa Barbara Channel for
Wednesday evening, with local SCA gusts possible for the inner
water south of Point Sal. For Thursday evening, there is a 60-80%
chance for SCA winds for the Santa Barbara Channel and a 30%
chance of local SCA winds for the inner waters off the coast of LA
and Orange Counties.

Expecting increasing southerly swell this weekend due to tropical
activity to the south. The details and timing are very much
dependent on the track of the tropical storm, but confidence is
moderate to high that the coastal waters will see a larger than
normal in southerly swell over Labor Day Weekend.

&&

.BEACHES...01/300 PM.

While there remains a range of outcomes in terms of the track of
Tropical Cyclone Marie, SoCal is likely to see an increasing
southerly-southeasterly swell this weekend into Tuesday (which may
combine with the swells from the current Hurricane Karina). This
most likely scenario would result in high surf advisories for
south facing beaches (Avalon, Long Beach Peninsula, Malibu, Point
Mugu) during a busy holiday weekend (especially Sunday into
Monday night), with very strong rip currents.

Additionally, evening high tides are expected to be around 7 feet
during portions of the event. As a result, there is an increasing
chance of moderate coastal flooding of low- lying areas and
significant beach erosion. There is a chance that coastal flood
advisories will be issued.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 6 AM PDT Wednesday for zones
      349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Thursday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Thompson/KL
AVIATION...Lewis
MARINE...Phillips/RS
BEACHES...Lewis/Gomberg/RS
SYNOPSIS...Lewis

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office