182
FXUS66 KLOX 300427
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
827 PM PST Sat Nov 29 2025

.SYNOPSIS...29/726 PM.

A cooling trend will continue through the weekend as onshore flow
returns. Warming is expected Monday as the flow pattern shifts to
offshore with gusty Santa Ana winds possible. A cooling trend
will develop Tuesday and Wednesday as a storm system approaches
the region. There is a chance of rain Wednesday through Thursday,
mainly south of Point of Conception.

&&

.SHORT TERM (SAT-TUE)...29/826 PM.

***UPDATE***

Low clouds have developed along the Central Coast, and are
expected to become widespread across all coasts and valleys
tonight through at least tomorrow morning. The marine layer is
currently around 700 feet deep at LAX airport and 1000 feet deep
at Vandenberg, an indicator that areas most likely to see dense
fog are locations away from the coast and elevated several hundred
feet above sea level (such as the San Fernando and San Gabriel
Valleys). Onshore flow Sunday may maintain clouds across much of
LA and Ventura Counties through the day.

***From Previous Discussion***

A shortwave ridge of high pressure aloft is starting to breakdown
as an upper-level trough of low pressure off the California coast
digs south offshore. Broader troughing aloft across much of the
Western States will bring a cooling trend as a colder air mass
from Canada pipes air from the north into the region through
Sunday. A return of low clouds and fog is expected tonight and
into Sunday morning as onshore flow will remain intact through
tonight.

As the trough axis slides by to the south, an offshore flow
pattern will develop. A colder air mass in the Great Basin will
set up high pressure near the surface and tighten the surface
gradient between the low pressure system offshore. There is a
moderate-to-high (30-50 percent) chance that advisory level
northeast winds will develop across the region between Sunday
night and Monday morning. The highest chance of gusty offshore
winds is placed with Santa Ana winds across the Southland, but
gusty Santa Lucia winds in San Luis Obispo County cannot be
ruled out. EPS ensemble wind gust means lean toward advisory
levels at typical sites like KCMA and K3A6, while multi-model
high-resolution ensembles fall inline with this idea. A wind
advisory for gusty Santa Ana winds was collaborated with
surrounding offices, but given the uncertainty, the best approach
was to wait and let a few more model runs handle it.

With offshore flow pattern slated to develop and the trough likely
to pull farther offshore, a warmer weather pattern will likely
develop across the region for Monday as compressional heating will
take place. As a result, a dry and warm day should be expected
for Monday.

A cold night looks to be setting up on Monday night and into
Tuesday morning. A northerly flow pattern aloft will likely
redevelop. With less winds, a drier air mass in place, and less
cloud coverage, radiative cooling processes will much more
efficient overnight Monday and into Tuesday morning. In wind-
sheltered areas, such as the interior valleys, there is a
moderate-to-high chance that a freeze watch may be needed as
overnight low temperatures could plummet to between 28 and 32
degrees in these areas.

The pattern will likely switch back to onshore on Tuesday as an
inside-slider type trough digs south out of Canada. A cooling
trend should be expected as onshore pressure gradients develop and
offshore flow breaks down.

.LONG TERM (WED-SAT)...29/133 PM.

The inside-slider trough will move into the region between
Wednesday and Thursday. There is a lot of uncertainty given the
cutoff nature of the system. While EPS forecast ensembles lean
wetter with the system than the forecast, the CMC and GEFS
solutions lean drier. EPS member solutions are starting to lean
drier and produce less precipitation in the current run relative
to last several. Given the time of year and the nature of the
trough, amounts with this storm will very likely be light at best.
A colder, showery, and windy pattern seems to be more of the story
with this system, but any changes in movement either farther
offshore or farther inland will produce different results.
Regardless, a much cooler air mass should be expected for
Wednesday and Thursday along with breezy to gusty winds. Frost
and freeze headlines will likely be needed either on Wednesday
night or Thursday night.

The latest forecast ensembles trend toward a warming trend for
the end of next week, but the air mass will likely to take a few
days to recover. A cold start to Friday morning could linger as a
colder and drier air mass will continue. CMC temperatures mean
suggest the coldest day of the stretch occurring on Thursday night
through Friday morning.

&&

.AVIATION...30/0333Z.

At 0022Z at KLAX, the marine layer was around 1000 feet deep. The
top of the inversion was near 2200 feet with a temperature of 17
degrees Celsius.

For the 00Z TAF package, overall moderate confidence in
forecasts. High confidence in VFR conditions for KWJF and KPMD,
with moderate to high confidence in KBUR and KVNY where there is a
20% chance of LIFR conds overnight. For coastal sites, moderate
confidence in current forecasts due to uncertainties with the
behavior of the marine layer. Timing of flight category changes
could be +/- 3 hours of current forecast with flight categories
off by 1 category.

KLAX...Moderate confidence in the 00Z TAF. Timing of flight
category changes could be +/- 3 hours of current forecasts. Also,
there is a 20% chance of LIFR conditions 08Z-14Z, and a 30% chance
of MVFR conds. No significant easterly wind component is
expected.

KBUR...Moderate confidence in the 00Z TAF. There is a 30-40%
chance that VFR conds prevail through the period.

&&

.MARINE...29/735 PM.

For the Outer Waters, moderate to high confidence in current
forecast. Through Sunday morning, high confidence in winds and
seas remaining below Small Craft Advisory (SCA) levels. Sunday
afternoon through Monday morning, there is a 30-50% chance of SCA
level winds. From Monday afternoon through Tuesday afternoon, high
confidence in winds and seas remaining below SCA levels. For
Wednesday, there is a 20-30% chance of SCA level winds. On
Thursday, high confidence in winds and seas remaining below SCA
levels.

For the Inner Waters north of Point Sal, high confidence in
current forecast. Winds and seas are expected to remain below SCA
levels through Thursday.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. Today through Thursday, winds and
seas are expected to generally remain below SCA levels. The only
exception will be on Monday with a 30-40% chance of SCA level
northeast winds from Ventura south to Santa Monica.

&&

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

&&

$$

PUBLIC...Hall/Schoenfeld
AVIATION...RAT
MARINE...RAT/CMC
SYNOPSIS...Hall/Ciliberti

weather.gov/losangeles

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