782
FXUS66 KLOX 041144
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
344 AM PST Tue Nov 4 2025

.SYNOPSIS...04/311 AM.

Broad troughing over the eastern Pacific Ocean will keep a cooler
than normal weather pattern in place through Thursday. An
atmospheric river type system in northern California will slowly
move southward into San Luis Obispo and Santa Barbara Counties
through Wednesday night, weakening as it moves down the state. A
warming trend will develop for late week as high pressure aloft
builds in.

&&

.SHORT TERM (TDY-THU)...04/318 AM.

The latest water vapor imagery shows an upper-level trough over
the eastern Pacific Ocean near 46N and 150W early this morning.
Moisture out ahead of the storm is starting to produce rain over
northern California. The system, an atmospheric river type storm,
will continue move south into Central California through
Wednesday night, falling apart as it moves down the state. Any
rainfall with this system will mostly remain over northern and
central California, but a few showers or night through morning
drizzle cannot be ruled out across the Southland.

Showers out ahead of the storm could develop across northwestern
San Luis Obispo County and the Santa Lucia range as early as this
evening. A warm air advective pattern develops along the Central
Coast of California this evening and should create a more
favorable environment for orographic lift to produce light
precipitation along the Coast Ranges. High-resolution multi-model
ensembles members favor high to likely chances for rain in the
Santa Lucia range tonight. While amounts will be light, rainfall
totals could start adding up in the places like Rocky Butte in
northwestern San Luis Obispo due to the favorable pattern. As the
storm moves closer to the region on Wednesday morning, periods of
rain will develop across northwestern San Luis Obispo County.
Rain will still be likely across much of the Central Coast on
Wednesday, but amounts will likely be lighter as the atmospheric
river will weaken and fall apart. To the south, the flow pattern
ahead of the storm could create periods of showers or widespread
and accumulation drizzle during the night and morning across
southern Santa Barbara County and southern Los Angeles County. A
moist flow pattern will likely upslope into the Transverse Ranges
and could produce some mountain showers across the Santa Ynez
mountains and maybe the Santa Monica mountains. A deep marine
layer depth, potentially lifting to near 4000 feet deep, could
interact with the upper-level dynamics to squeeze out some
precipitation. Rainfall amounts with the system will generally be
a tenth of an inch or less, except for a quarter to three quarters
of an inch in northwestern San Luis Obispo County. That being
said, there is a 30 percent chance that local amounts could add up
higher than that in the Santa Lucia Mountains.

Breezy south to southwesterly winds could develop between tonight
and Wednesday across San Luis Obispo County, across the interior
portions of the area, and out into the Antelope Valley. There is
a moderate chance that a wind advisory could be needed late
tonight and into Wednesday across the San Luis Obispo County
valleys and the Santa Lucia mountains. The latest NAM-WRF
solutions indicate 950 mb winds approach 20 to 25 knots, putting
it in a marginal category as the storm system advances on the
Central Coast. Wind advisory level winds could also develop in the
Antelope Valley on Wednesday afternoon and evening as 850 mb
winds will increase as the surface pattern tightens with the
approaching storm. The latest ensemble members do not add much in
the way of confidence, leaning more toward the weaker side of
advisory criteria for each area.

Snow levels will remain quite high as the coldest air with storm
stays well north of the area, but a cooler than normal air mass
will be in place for today and Wednesday as onshore flow
strengthens out ahead of the storm. The coolest day of the week
for most areas is likely to be Wednesday.

There is a high chance that upslope showers could linger into the
northern slopes of the mountains on Thursday morning. A wind
advisory could also be needed as well as the system`s colder air
mass will slam up against the northern slopes of the mountains and
create thermal and pressure gradients across the Interstate 5
Corridor. At this time, the latest EPS wind gust means suggest
the winds being sub-advisory at KSDB.

Otherwise, ridging aloft will begin to build in on Thursday and
temperatures will start to warm up across the region. A warming
and drying trend will establish and continue into the end of the
week.

.LONG TERM (FRI-MON)...04/318 AM.

The warming trend will sharpen on Friday as weak offshore flow
develops beneath upper-level ridging aloft. The ridge axis looks
to nose into the state late Friday as 500 mb heights climb and
850 mb temperatures warm. Temperature in the mid 70s to upper 80s
will be common Friday and Saturday across coastal and valley
areas, likely producing daytime high temperatures between 6 and 12
degrees above normal for this time of year.

The earliest chance of cooling will be Sunday when the ridge axis
slides east, but there is a moderate chance that a warm weather
pattern could linger into early next week. The latest cluster
analysis suggests the ridge lingering over the West into at least
Tuesday, but the main questions will be how strong the ridge will
be, and how much offshore flow will remain?

The ensemble members are still advertising a pattern change to a
wet weather pattern sometime next week. A broad wet pattern could
develop sometime between next Tuesday and the end of the week.
Forecast ensemble means lean toward somewhere between one to two
inches of rain to affect the region, the bulk of it likely
occurring late next week. Almost four-fifths of the EPS AI
perturbations give the region over one inch, an almost half of the
EPS AI members produce two inches. Almost of all the GEFS, EPS,
and CMC forecast ensemble members have rain a some point after
Tuesday. What needs to be determined still is the exact timing,
amounts, and impacts associated should the wet pattern materialize
as progged. With much time until then and many more model runs to
build or decay confidence, people should monitor the latest
forecasts or stay tuned here.

&&

.AVIATION...04/1144Z.

At 0753Z at KLAX, the marine layer was 900 ft deep. The top of
the inversion was at 2200 feet with a temperature of 20 C.

High confidence in TAFs for KPRB, KWJF and KPMD.

Moderate confidence in the remainder of TAFs. Timing of CIG/VSBY
restrictions may be of +/- 2 hours & flight minimums by one cat.

KLAX...Moderate confidence in the 12Z TAF. CIGs may scatter out
from around 21Z Tuesday to 03Z Wednesday (30% chance). Otherwise,
expecting CIG heights to gradually deepen through fcst period,
with a small chance for intermittent IFR CIGs 008-009 through 15Z
Tuesday. Forecast sounding data suggest that the 2000ft threshold
could be reached around 06Z Wednesday (+/- 2 hours). 10% chance
that east wind component reaches 7-8 knots from 10Z to 17Z Wed.

KBUR...Low confidence in the 12Z TAF. 10% chc of VLIFR Conditions