275
FXUS66 KLOX 202228
AFDLOX

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

.SYNOPSIS...20/105 PM.

A storm will bring rain and mountain snow to the area through
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-SUN)...20/225 PM.

Very little has changed with the assessment of this storm and the
expected impacts aside from the arrival of rain today was a few
hours ahead of schedule. The initial round of precipitation has so
far lived up to its billing of mostly light rain under a tenth of
an inch per hour. This will more or less remain the case through
early this evening as it advances through LA County. Meanwhile,
along the Central Coast rain will be tapering off this afternoon
and evening in most areas except for the far interior sections
east of the Santa Lucias where scattered showers may continue into
Friday morning. Amounts there have been under a half inch in most
locations so far and any additional rain is expected to be on the
lighter side.

For the second part of the storm tonight into Friday models have
been consistent showing a very favorable severe weather threat
across LA County, and in particular the southern part of the
county. A strong vorticity lobe is expected to pinwheel around Pt
Conception later tonight, resulting in backing winds inland and
northwest flow over the Santa Monica Bay resulting in a large
scale counter-clockwise rotation centered right over southern LA
County. The forecast sounding for KLAX shows the backing winds
towards the surface and a hodograph that could certainly support
rotation and a small tornado. CAPE values close to 1000J/kg will
support moderate updrafts that will be favorable for storm
initiation. Overall, the pattern looks consistent with previous
severe weather outbreaks, either from strong straight line winds
from storms, heavy rain, or from a small tornado. The most
favorable area appears to be southeast LA County from Pasadena to
LA/Orange County line, but this could shift east or west depending
on the ultimate track of the upper low.

Periods of heavy rain are likely at times overnight in LA County
and high res models continue to indicate a 10-20% chance of rain
rates reaching 1 inch per hour. WPC also has this area in a
marginal risk for flooding. This will be a much more scattered
heavy rain event than the last event so not all areas will get
these rates, but the areas that do will could have significant
hydrologic impacts.

The heavy rain potential is expected to decrease Friday morning,
however, scattered showers are possible through the day with rain
rates generally a quarter inch per hour or less.

Also of interest Friday is the increase in northeast winds
creating a semi-wet Santa Ana event across portions of LA and
Ventura Counties. A low end wind advisory may be needed tomorrow
in the usual Santa Ana wind favored areas.

While the Santa Ana wind will have a detrimental affect on the
shower chances across the coast and valley areas, the north facing
mountain slopes will benefit from upslope flow that will maintain
the shower potential into Saturday. Can`t completely rule out a
shower at lower elevations but any precip would be isolated and
brief.

Several inches of snow in the mountains are expected with this
system with the snow level around 6000 feet. Could see 8-12 inches
of snow by Saturday in the LA County mountains above 8000 feet
with the beneficial upslope flow Friday and Saturday.

Sunday is expected to be dry but on the cooler side.

.LONG TERM (MON-THU)...20/226 PM.

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...20/201 PM.

Low confidence in forecast, especially regarding winds. It is
best to alter any plans and remain in safe harbor until conditions
improve this weekend.

A storm system will continue to move south before stalling
inside the Southern California Bight, bringing periods of gusty
winds, a large west- northwest swell (especially for the Outer
Waters), rain, and potential thunderstorms into the weekend. The
highest thunderstorm chances are from tonight into Friday
morning. Any thunderstorm can produce erratic wind shifts, heavy
rain, lightning, and even waterspouts. There is a 10% chance for
brief Gale Force winds south of Point Conception through late
tonight.

A combination of Small Craft Advisory (SCA) winds and seas will
be common across the coastal waters through much of the weekend.
Seas will 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 by late tonight. Wind
directions will vary considerably through the course of the storm
which will will result in rough, confused seas, especially south
of Point Conception.

NE winds will become common tonight through Saturday morning as
the core of the storm system remains nearly stationary and spins
inside the Southern California Bight. Winds will be strongest from
Ventura to Santa Monica (20-30 knots), but NE winds gusting up to
25 knots will occur nearshore from Palos Verdes south through
Orange County. NE winds may reach the Channel Islands, but much
lower chances for Catalina Island.

&&

.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...Flood Watch in effect from 10 PM PST this evening through
      Friday morning for zones 88-362-366>373-379-380-548. (See LAXFFALOX).
     High Surf Advisory in effect until 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 remains in effect until 10 AM PST
      Friday for zone 377. (See LAXWSWLOX).
     Winter Weather Advisory remains 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 9 PM this evening to 4 PM
      PST Friday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 6 PM this evening to 4 PM
      PST Friday for zone 655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Saturday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/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