424
FXUS66 KLOX 201806
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1006 AM PST Thu Nov 20 2025

.SYNOPSIS...20/919 AM.

A storm will bring rain and mountain snow to the area today into
Saturday morning, heaviest tonight into Friday morning in Los
Angeles County. Gusty east winds are expected Friday in some
areas. High pressure will push temperatures back to normal this
weekend which will continue through the holiday week.

&&

.SHORT TERM (TDY-SAT)...20/1006 AM.

***UPDATE***

The rain is arriving a couple hours earlier than expected but
otherwise more or less on track. Rain rates with this initial
round are expected to be under a quarter inch per hour and in most
cases under a tenth of an inch. And for most of SLO and SB
Counties this initial batch of rain will be 90% or more of the
total for the storm. Elsewhere, and especially in LA County,
showers will continue into Friday with the potential for heavy
showers and thunderstorms. Hi res models have been consistent
showing a strong signal for storms overnight (between 10pm and
6am) tonight in southern LA County with a 30-40% chance of rain
rates up to or locally exceeding a half inch per hour. Still not
expecting to issue any flood watches at this time but periods of
heavy rain are possible tonight in LA County.

***From Previous Discussion***

In general, the storm system remains on track to impact the area
today through Friday, maybe into Saturday, with minimal changes
to the expected impacts and details.

RAIN IMPACTS: Focused over Los Angeles and Ventura Counties,
especially Thursday afternoon and night. With the soils still
soggy from the recent rains, the additional rain will bring an
enhanced risk for mudslides over vulnerable areas, and rock
slides on the canyon roads with additional closures. More traffic
than usual with slippery roads and minor flooding. The risk for
burn scar debris flows is not zero but very small (5% chance) and
tied to an unfortunate thunderstorm forming right over a burn
scar. This low risk is especially so considering the minimal
impacts from the recent heavy rains. Flood Watches are NOT
expected.

SNOW IMPACTS: Focused over Los Angeles and Ventura Counties, where
Winter Weather Advisories are in effect. Snow levels will
generally be 6000 feet or above for most of the precipitation, but
will likely lower to 5000 feet at times. This means some mountain
roads and communities will see accumulating snow and icy
conditions.

THUNDERSTORM IMPACTS: Thunderstorms and/or enhanced cells will
become more likely later this afternoon through most of the day on
Friday. Isolated heavy downpours and wind gusts up to 50 mph are
possible with any of these storms. Lightning could affect coastal
areas and beaches. There is a remote risk for a tornado, mainly
over Los Angeles County Thursday night.

WHAT YOU CAN DO: Limit time on the roads and outside. Stay weather
aware. If you hear thunder, see lightning, or experience sudden
wind shifts, head indoors. If you have to travel in the mountains,
bring chains or a 4x4 vehicle. Continue to monitor the latest
forecasts.

DETAILS: Our next storm system is headed our way. A long and
narrow cold front is currently working through San Fransisco and
Monterey and will sweep down the coast today and tonight. Widespread
light to moderate rain will affect all four of our counties. By
this evening, the center of the low pressure system driving this
front will drop south quickly and into the southern California
waters by Friday morning. This will also destabilize the
atmosphere by tonight and bring a 10-20 percent chance of
thunderstorms and heavier rain cells which lingers into Friday.
With a fair amount of wind shear, there is a remote risk (less
than 2% chance) of a brief tornado, mainly over Los Angeles
County. The path of this low will also force some rather gusty
east winds on Friday in what one might call a wet Santa Ana. These
winds will likely occur over a big area than usual. Expecting
impactful delays at LAX airport with a long duration period of
east wind operations.

The unusual evolution of this storm will reverse the typical
distribution of the rain, with the higher totals and rates to the
south compared to the north. The cutoff nature of the system
means there will be a larger range of potential outcomes than
usual, including timing with an 6-12 hour earlier or later end
than currently advertised both on the table. The path of the
system and the resulting drying east winds also adds to that range
of outcomes, but will enhance the rain and snow for the backside
mountains and deserts. With all that stated, the most likely
outcomes are as follows. For SLO and Santa Barbara Counties, look
for totals of 0.25 to 0.75 inches, with local 0.5 to 1.5 inches
in some mountains. Peak rates of 0.10 to 0.25 inches per hour,
except for local 0.25 to 0.50 inches per hour in thunderstorms.
For LA and Ventura Counties, look for totals of 0.75 to 1.25
inches, with local 1.0 to 2.0 inches in some mountains. Peak rates
of 0.2 to 0.4 inches per hour, except for local 0.50 to 0.75
inches per hour in thunderstorms. Snow amounts for elevations
above 6,000 feet will be 2 to 6 inches, highest in LA and Ventura
Counties. Local 8 inches are possible. Light accumulations down to
5,000 feet. Decided to convert the previous Winter Storm Watch to
a Winter Weather Advisory as the snow rates just do not look that
heavy. Precipitation over the Tejon Pass/Grapevine should stay as
rain through the event, but could be heavier than our previous
storms.

Temperatures will be cool today and Friday, but with the east
winds some coastal areas will likely see warming on Friday. By
Saturday, all areas will see warming as the low should move
through and the east winds continue. In fact, we could see highs
in the lower 70s.

.LONG TERM (SUN-WED)...20/350 AM.

While temperatures might cool a little on Sunday as the east winds
turn off and return to a more normal onshore pattern, temperatures
will remain around normal through next week (including
Thanksgiving). The marine layer with low clouds and fog should
also make a return, but might be limited by Wednesday as north
winds start to form. A rain-free period through at least Black
Friday looks almost certain. There are growing signals however for
another storm sometime in the Saturday through Tuesday time range
(Nov 29-Dec 2).

&&

.AVIATION...20/1801Z.

At 1739Z at KLAX, there was a deep moist layer to 5500 feet, with
an inversion to 8000 feet and a temperature of 1 degree Celsius.

A storm system will bring widespread rain on Thursday with at
least MVFR categories and possible localized IFR conditions during
the heaviest rain, with the highest chance of that over LA and
Ventura Counties 20-03Z. LLWS 5-15 knots likely at most airports.
10-20% chance of thunderstorms 20/23Z-21/18Z, highest for Ventura
County and Los Angeles County. Moderate confidence in timing (+/-
3 hours).

KLAX...Moderate confidence in TAF. -SHRA followed by consistent
rain will continue into late tonight. IFR cigs and vsbys possible
with any heavy rain, best chances between 00Z-08Z. MVFR and VFR
cigs are most likely outside of heaviest rain. 20% chance of
TSTM 00Z-16Z. Any TSTM will likely produce very gusty and erratic
winds. Winds will remain east-southeast through the period. There
is a 30% chance for east winds to reach 15-20 kts as soon as 04Z,
strongest winds 07Z-end of period.

KBUR...Moderate confidence in TAF. -SHRA followed by consistent
rain will continue into late tonight. IFR cigs and vsbys possible
with any heavy rain, best chances between 23Z-07Z. MVFR and VFR
cigs are most likely outside of heaviest rain. 10% chance of TSTM
23Z-12Z. Any TSTM will likely produce very gusty and erratic
winds. Gusty SE winds will e common

&&

.MARINE...20/820 AM.

A storm system will move south along the California Coast,
bringing gusty winds, a large west- northwest swell, rain, and
potential thunderstorms Thursday into the weekend. The highest
rain and thunderstorm chances exists from Thursday afternoon
through Friday afternoon. Any thunderstorm can produce erratic
wind shifts, heavy rain, lightning, and even waterspouts.
Wind directions will vary considerably through the course of the
storm. This will result in rough, confused seas. Due to lack of
confidence in exact location of storm`s core, Gale Force winds
are possible virtually anywhere across the coastal waters.
However, more likely south and west of Point Conception.

A combination of Small Craft Advisory (SCA) winds and seas will
be common across the coastal waters through much of the weekend.
Seas will rapidly increase to upwards of 15 feet across the Outer
Waters, 10 feet for the nearshore Central Coast Waters, and 5 to
8 feet inside the Southern California Bight through this evening.
10-20 knots southerly winds are expected ahead of cold frontal
passage, and NW winds 20-30 knots expected in the wake of the
front.

High resolution models indicate that the low will remain
far enough north impacting the inner waters south of Point
Conception with an extended period of SCA conditions and
thunderstorm chances into at least Friday afternoon.

On the heels of the system moving through, a moderate Santa Ana
Wind event will develop. Northeast winds 20-30 knots will be
common nearshore from Ventura to Malibu Friday morning through
Saturday evening. There is a moderate chance these winds reach the
Channel Islands across the Santa Barbara Channel. Northeast to
southeast winds 10-20 knots with gusts to 25 kt at times are
likely nearshore from the Palos Verdes Peninsula south through
Orange County. Models have been trending down slightly, so it is
unlikely at this point for winds of that magnitude to reach
Catalina Island.

Confidence remains low in the forecast for winds, especially
south of Point Conception, as the direction and magnitude of
winds is highly dependent on the track of the upper level low
pressure system. It is best to alter any plans and remain in safe
harbor until conditions improve.

&&

.BEACHES...20/404 AM.

High Surf Advisories are now in effect from Today through Sunday
night along the Central Coast and Ventura County. There is a 30%
chance for High Surf Advisories to be issued for the Los Angeles
County coasts during that timeframe.

Highly variable winds will create rough surf conditions across all
coasts. In addition, there is a chance for thunderstorms Thursday
through Friday night at all beaches. Thunderstorms can produce
lightning, heavy downpours, gusty- erratic winds, and even
waterspouts.

Beach erosion with isolated, minor coastal flooding is possible
for west-northwest facing beaches, especially during peak high
tide from 8 AM to 1 PM from Friday through Sunday, with highest
risk along the Central Coast.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect from 3 PM this afternoon to 3 AM
      PST Monday for zones 340-346. (See LAXCFWLOX).
     High Surf Advisory in effect from 3 AM Friday to 3 AM PST
      Monday for zone 354. (See LAXCFWLOX).
     Winter Weather Advisory now in effect until 10 AM PST Friday
      for zone 377. (See LAXWSWLOX).
     Winter Weather Advisory in effect until 4 PM PST Friday for
      zones 379-380. (See LAXWSWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Friday for zone
      645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      PM PST Friday for zones 650-655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Saturday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Kittell/RK
AVIATION...Lewis
MARINE...Lewis
BEACHES...Lewis/Black
SYNOPSIS...MW/RK

weather.gov/losangeles

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