109
FXUS66 KLOX 131755
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
955 AM PST Thu Nov 13 2025

.SYNOPSIS...13/925 AM.

A large storm system will move into the Central Coast this
afternoon and will continue further south tonight into Friday.
The storm will generate periods of moderate to heavy rain this
evening through Saturday, and possibly into early next week.
Flooding of roadways and burn scars is possible, especially
Friday and Saturday.

&&

.SHORT TERM (TDY-SAT)...13/954 AM.

***UPDATE***

No significant changes to the forecast. A large and slow moving
storm is approaching the area. There have been a few stray
sprinkles but the first bands of heavier rain are still at least
several hours away, and in the case of LA County not until Friday
morning at the earliest and more likely Saturday with the second
burst of rain as the upper low is expected to move through. A
Flood Watch has been issued for southern Santa Barbara County,
including the Santa Ynez Range, and the southern Ventura County
mountains later tonight through noon Friday with the initial
impulse coming through creating rain rates up to an inch per hour
in the upslope areas. As this impulse moves east into LA County
and farther away from the upper low Friday morning it will weaken
but could still produce some isolated rain rates up to a quarter
inch per hour. Light to occasionally moderate showers will
continue across Ventura and LA Counties Friday afternoon into
early Saturday morning before the second impulse arrives around
daybreak Saturday, though there are still uncertainties with this
second one. Will be considering a Flood watch issuance for
Saturday for all areas south of Pt Conception this afternoon.

***From Previous Discussion***

POTENTIAL FOR SEVERAL INCHES OF RAIN ACROSS THE AREA WITH MAJOR
IMPACTS MAINLY FRIDAY AND SATURDAY.

A large long wave pattern covers the CONUS with a huge ridge
covering a width from NV to MO. A compact low is moving up the
backside of the ridge, but will not be able to make much eastward
progress and this will allow it to affect CA for the next 3 days
with an emphasis on Srn CA on Friday and Saturday.

Today will not be that action packed as the system is still a ways
off of the coast. Rain will likely develop across NW SLO county
later this morning. Rain will overspread the entire Central Coast
late this morning and during the afternoon as the front moves into
the area. Rainfall amounts will mostly be under a quarter inch
with the usual exception of the far NW tip of SLO county where
.75" of rain could fall. The sfc gradient will increase over SLO
and SBA counties as the front approaches. The winds will increase
in kind and advisory level wind gusts will develop across much of
the two county area. A Wind Advisory from 8 AM to 6 PM is in
effect for south wind gusts up to 45 mph. The rest of the area
will see partly cloudy skies turning mostly cloudy during the
afternoon. Max temps will mostly be in the 60s up and down the
csts and vlys.

Tonight through the predawn hours Saturday the low will move due
south and will end up 250 miles to the SW of Pt Conception. At the
same time a front that originates well to the north of the area
and is separate from the upper low will push through the area.
The entire area will get rain during this period. The strongest
rain will occur over the Central Coast at this time. From late
this evening through dawn the front and the heaviest rain will
move across southern SBA county and

However, there are some solutions that place the upper low in a
much less favorable location that results in quite a bit less
rain. This is a less likely scenario than the one above but still
possible. By Thursday there should be more clarity on the track of
the low and at that point consideration will be given to any
possible Flood watches.  VTA county. It is during this
period when the south flow ahead of the front will interact with
the transverse ranges and produce the heaviest rain. Rain will
move in to LA county around dawn and the entire morning commute
will be wet. Mdls have consistently shown the front weakening as
it moves over LA county and rainfall rates and amounts will likely
end up not as strong as they were over srn SBA county and VTA
county. Still the Malibu area could see a period of heavier rain
right around sunrise. There will be a lull in the rainfall in the
afternoon with even some dry periods (esp for the Central Coast)
and much less in the way of rainfall rates. Peak Rainfall rates
will be mostly around a half inch per hour except across the south
facing slopes from Pt Conception to Ventura county where 1 inch
per hour rates will be possible. There is also a slight chc of a
TSTM with the threat mostly confined to the Central Coast.
Rainfall totals for most of the csts and vlys will be around an
inch (.5 to .75 inches for LA County) with the exceptions of NW
SLO and the transverse range coast

However, there are some solutions that place the upper low in a
much less favorable location that results in quite a bit less
rain. This is a less likely scenario than the one above but still
possible. By Thursday there should be more clarity on the track of
the low and at that point consideration will be given to any
possible Flood watches.

There is still some uncertainly in the Friday night Saturday
forecast as it involves the trajectory of a cut off low. Ensemble
forecasts and the short range hi rez mdls are currently favoring a
trajectory (sweeping up to the NE and over LA/Orange counties)
that will be favorable for another burst of moderate to heavy
rain. This system will bring the heaviest rain to areas south of
Point Conception. The key factor with this system will be its PWAT
values which are a little over 1.5 inches as it picks up some sub
tropical moisture. As mentioned there is less certainty with this
system but it looks like it will deliver an additional 2 to 4
inches of rain with the peak occuring Saturday morning. Again
rainfall rates would be in the half inch per hour with local one
inch per hour amounts possible. Much less rain will fall across
the Central Coast - a half inch to an inch.

With this in mind, residents, especially those in vulnerable
areas, should start taking precautions immediately to prepare for
the storm and protect their interests. This scenario would
potentially create many significant impacts area-wide, including
possible debris flows in the burn areas, significant ponding of
roads and highways, mudslides through the canyons, fallen trees,
etc.

Later today both systems will be well in the range of the hi rez
short range weather mdls and ensembles. These will be analyzed
and decisions will be made on the issuance of any needed Flood
Watches.

.LONG TERM (SUN-WED)...12/1154 PM.

Both the EC and GFS while not in the greatest synoptic agreement
show enough moisture and energy to keep a 30 to 40 percent chc of
rain in the forecast through the period. Much of these pops are
likely the result of ensemble smearing and there will be some dry
periods as well as wet ones. PWs are much lower than during the
Fri/Sat stormy period and additional rainfall amounts across the
entire 4 day period will probably end up in the half inch to 1
inch range. That said this weather pattern has be so changeable
would not be surprised if this period`s actual weather turns out
to be something else.

Good confidence that there will be little day to day changes in
the temperatures. Max temps will mostly be in the lower to mid
60s across the csts/vlys which is 6 to 12 degrees blo normals.

&&

.AVIATION...13/1710Z.

At 1645Z at KLAX, the marine layer depth was around 500 feet. The
top of the inversion was near 2300 feet with a temperature around
17 degrees Celsius.

Overall, moderate confidence in 18Z TAF package. High confidence
in rain impacting all sites through the period. However, low
confidence in timing of rain, and associated CIG and VSBY
restrictions, could be +/- 4 hours of current forecasts.

There is a 10-20% chance of thunderstorms from KSBA northward in
the 21Z-12Z time frame. Any thunderstorms that develop will be
capable of producing frequent lightning, brief heavy rain and
gusty/erratic winds.

KLAX...Overall...moderate confidence in 18Z TAF. High confidence
in rain developing through the period, but low confidence in
timing of rain, and associated CIG and VSBY restrictions, could
be +/- 4 hours of current forecasts. Winds will shift to an
easterly direction after 03Z with high confidence in easterly
winds above 8 knots in the 10Z-20Z time frame.

KBUR...Overall...moderate confidence in 18Z TAF. High confidence
in rain developing through the period, but low confidence in
timing of rain, and associated CIG and VSBY restrictions, could
be +/- 4 hours of current forecasts.

&&

.MARINE...13/910 AM.

High confidence in the forecast for impacts and moderate
confidence for timing. A storm system will bring gusty winds,
steep short period seas, and a slight chance of thunderstorms
across the entire waters through at least Saturday morning. Any
thunderstorms that develop will be capable of producing frequent
lightning, gusty and erratic winds, locally rough seas and even
waterspouts. These will be dangerous conditions for boaters,
especially for the coastal waters along the Central Coast to the
western Channel Islands with gale force winds, steep choppy waves,
and seas in excess of 10 feet. Boaters are advised to remain in
safe harbor.

Expecting Small Craft Advisory (SCA) conditions to become more
widespread for the waters southwest to northwest of the Channel
Islands including the nearshore Central Coast waters into this
morning from northwest to southeast. Gale Force winds are expected
for the waters adjacent to the Central Coast, including
nearshore, from this morning through this afternoon. 20-30 knot
winds will follow. Seas will build to hazardous levels (up to 15
feet) throughout today, then likely decrease to below 10 feet
after Saturday morning.

Inside the California bight, winds and seas will remain below SCA
levels through this morning, then winds will begin to increase
this afternoon. SCA level south-southeast winds (20-30 knots)
will be common through at least early Friday morning, but there is
a moderate chance that SCA conditions (winds and seas) may linger
into Friday evening. Ocean conditions are then expected to be
relatively calm for the rest of the weekend.

&&

.BEACHES...13/109 AM.

A moderately long period west-northwest swell will bring hazardous
surf conditions to portions of Southwest California late Thursday
through at least Saturday morning. In addition to the west-
northwest swell, a storm system will bring produce southerly winds
which will add a southerly wind swell component to the surf. High
Surf Advisories have been issued for the Central Coast and
Ventura County beaches. Please refer to the CFWLOX and SRFLOX for
details.

There is a chance for High Surf Advisories to be issued for Los
Angeles County (50%) and Santa Barbara County (20%) for the late
Thursday night to early Saturday morning period.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 6 PM PST this evening for zones
      340>348. (See LAXNPWLOX).
     High Surf Advisory in effect from midnight tonight to 9 AM
      PST Saturday for zones 340-346. (See LAXCFWLOX).
     Flood Watch in effect from late tonight through Friday
      morning for zones 349>352-376. (See LAXFFALOX).
     High Surf Advisory in effect from 3 AM Friday to 9 AM PST
      Saturday for zone 354. (See LAXCFWLOX).
PZ...Gale Warning in effect until 4 PM PST this afternoon for
      zones 645-670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 4 PM this afternoon to 3
      PM PST Friday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Saturday for
      zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...RAT
MARINE...Lewis/RAT
BEACHES...Lewis
SYNOPSIS...MW/CC

weather.gov/losangeles

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