147
FXUS66 KLOX 261626
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
926 AM PDT Tue Aug 26 2025

.SYNOPSIS...26/909 AM.

Mostly sunny skies today except for some afternoon clouds and
possible thunderstorms over the mountains and Antelope Valley.
There will be noticeable cooling today across the coast and
valleys followed by a very slow warming trend that will last
through the Labor Day weekend with high near to slightly above
normal.

&&

.SHORT TERM (TDY-THU)...26/925 AM.

***UPDATE***

Low clouds filled in rapidly this morning with tops all the way up
to 2200 feet. Oddly, gradients are actually slightly weaker than
yesterday but that could be at least partially in response to the
convection that occurred around the state overnight. In any case,
the explosion of low clouds this morning is definitely a sign that
cooling is in our immediate future, and the 24 hour change map
shows that in spades today with with most areas down at least 4-8
degrees from yesterday at this time and some as much as 15 degrees
cooler.

The NKX sounding this morning is still quite unstable with PW`s
still in the 1.5" range. Meanwhile, the VBG sounding is much drier
and very stable so it difficult to say exactly where the western
boundary of the convection will be, but likely still around the
Ventura mountains. While CAPE values are still impressive for this
region (around 2000 j/kg), the bases remain very high, around
10000 feet, so like the last couple days there will be good
potential for downburst winds and dry lightning, but also with
very small cores of heavy rain that will likely miss the rain
gauges. Overall, expecting similar rain rates as the last couple
days, mostly under a half inch but with very small pockets of
rates as high as .75/hr. The highest rates would be in the eastern
San Gabriels where the PW`s are highest.

***From Previous Discussion***

The VTA/LA mtns, the Antelope Vly, and possibly the NE portion of
SBA county will see CU and then towering CU develop starting
early in the afternoon. A slight chc of TSTMs will develop over
most of these mtns and the steering flow will push them into the
Antelope Vly. The best chc (~40%) for TSTMs will occur over the
eastern San Gabriel Mtns. These storms look to be fairly high
based which means the principle hazards will be downburst winds
and dry lightning. A few ensemble forecasts show a little more low
level moisture so there is a non zero chc of the TSTMs producing
heavier rains which would produce flooding hazards esp in and near
to the Bridge Burn Scar. Most areas will experience noticeable
cooling today with many temps in the area falling 3 to 6 degrees
from ydy`s values. A less robust marine layer may make portions of
the Central Coast the exception with a few degrees of warming.

A high hgt (583 dam) upper low moves just to the west of the state
on Wednesday bringing with it dry SW flow. This will eliminate the
monsoon threat. The change in flow and lower humidities should
allow for better marine layer coverage along the coast, but there
is a chc that it will be reluctant to form again. The drier air
will allow for some warming (1 to 2 degrees).

Not much change slated for Thursday. The upper pattern sets into
a classic trof to the NW upper high to the SE pattern with Srn CA
in between with dry NW. Most max temps will warm a degree or two.
Most max temps will be within a couple degree of normals.

.LONG TERM (FRI-MON)...26/259 AM.

The upper pattern will be fairly static through the long term,
which covers the Labor Day Weekend. CA will be sandwiched between
a trof to the NW and an upper high to the ESE. This pattern will
not change much through the period. At the SFC look for a fairly
constant pressure pattern with the W/E gradient varying between
weak onshore in the morning and mdt onshore in the afternoon. The
N/S gradients will be weakly offshore in the morning and then
weakly onshore in the afternoon.

The one thing that will be different is that on Friday the
moisture from former tropical storm Juliette will wash over the
area bringing partly ocnl mostly cloudy skies to the area and
enough mid level moisture to warrant a slight chc of TSTMs over
the LA mtns.

Night through morning low clouds are forecast everyday. This might
be overdone, however, as the mdls have been more wrong than right
about the marine layer fcst for the past week. If the low clouds
do develop they will only affect the coasts and the Santa Ynez
Vly.

Unremarkable weather will then dominate the area from Saturday
though Monday. The slow warming trend that kicked off Wednesday
will continue through Sunday, although if there are enough mid and
high clouds Friday will end up cooler. By Sunday max temps will be
near normal with 80s across the coasts (70s at the beaches) and
80s in the vlys.

Not looking at any real wind issues. There will likely be some sub
advisory Sundowner winds across the western portion of the SBA
south coast east evening.

&&

.AVIATION...26/1142Z.

At 0652Z at KLAX, the marine layer was 700 feet deep. with an
inversion top at 2500 feet with a temperature of 26 C.

Moderate to high confidence in valley/desert TAFs, and moderate
confidence in coastal TAFs. There is a 10-20% chance of IFR cigs
developing until 16Z at KPRB, KSBP, and KSBA. Timing of cig
arrivals tonight for coastal sites may be up to 3 hours off of
current forecast, and one category off at times.

There is a chance of thunderstorms from 20Z Tue to 02Z Wed across
the Antelope Valley and high elevation interior mountains.

KLAX...Moderate confidence in TAF, cig clearing may be off by 1.5
hours today, and the return of cigs tonight may be off by up to 3
hours. No significant easterly wind component is expected.

KBUR...High confidence in TAF.

&&

.MARINE...26/742 AM.

For the Outer Waters, moderate to high confidence in current
forecast, with Small Craft Advisory (SCA) conditions unlikely
through tonight. Wednesday through Saturday, there is a 30-50%
chance of SCA winds, mainly around Point Conception during the
afternoon and evening hours.

For the Inner Waters north of Point Sal, high confidence in winds
and seas remaining below SCA levels through Saturday.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For the western half of the Santa
Barbara Channel, there is a 20-30% chance of SCA level winds
through Saturday, mainly during the late afternoon and evening
hours. For the remainder of the southern Inner waters, winds and
seas are expected to remain below SCA levels through Saturday.

&&

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

&&

$$

PUBLIC...MW/Rorke
AVIATION...Schoenfeld
MARINE...Schoenfeld/Lewis
SYNOPSIS...MW

weather.gov/losangeles

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

NWS Flagstaff Office