Topanga, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

314
FXUS66 KLOX 130311
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
811 PM PDT Sat Sep 12 2026

.SYNOPSIS...12/541 PM.

Near normal temperatures are expected on Sunday, followed by below
normal temperatures through at least Wednesday. Low clouds will
affect coastal areas during the night to morning periods, along
with gusty onshore winds each afternoon. Warming is likely to
return towards the end of this coming week.

&&

.SHORT TERM (SAT-TUE)...12/810 PM.

***UPDATE***

Gradual cooling has affected the region over the past couple of
days, with max temperatures near to slightly above normal today.
Highs along the coast were in the 70s to lower 80s, with mid 80s
to mid 90s over the interior. Additional slight cooling is
expected tomorrow, lowering to near or slightly below normal. The
most significant temperatures drops are likely to occur over the
far interior, lowering around 6 to 10 degrees below today`s highs.

Gusty winds are affecting portions of the area, including NW to N
Sundowners over the western Santa Barbara South Coast where gusts
are increasing to over 40 mph at of 700 PM. Wind Advisories are
in effect for the whole South Coast and adjacent Santa Ynez
Foothills through 6 AM Monday. Across the eastern sections where
north to northeast winds are expected, speeds may be slower to
rise to advisory levels. KSBA to KBFL gradients are forecast to
increase further Sunday night compared to tonight. Gusty northerly
winds will affect other areas north of Point Conception,
including the Central Coast south of Morro Bay and the Santa
Lucias. Northerly winds will also increase through the Grapevine,
possibly reaching Advisory levels Sunday night.

Breezy onshore winds are affecting interior areas as well, such as
the passes and canyons into the Antelope Valley and interior SLO
County, and are expected to occur each afternoon to evening
period.

Night to morning low clouds and fog will mainly affect coastal
areas thanks to light offshore flow over the next several days.

***From Previous Discussion***

A relatively quiet stretch of weather will continue over the next
several days across southwestern California. Areas south of Point
Conception will see cooling through Wednesday, with highs
generally cooler than mid-September averages, especially Monday-
Wednesday. The combination of light offshore flow in the overnight
through morning period and limited marine layer cloud cover
(thanks to the offshore flow) will result in slight warming over
the Central Coast Sunday and Monday, with a cooling trend taking
the reigns Tuesday-Wednesday. More noticeable will be the much
less muggy feeling weather at atmospheric mositure is much lower
than last week, and will continue to decrease through tonight.

Breezy onshore winds will be common each afternoon, with some
gusty northwest to northeast winds across some interior and even
some coastal mountains (eastern Santa Ynez/Santa Lucias), with a
low to moderate chance for wind advisories to be needed for Sunday
night in windiest areas, such as the Grapevine area.
Additionally, gusty Sundowner winds will impact southern Santa
Barbara County through Monday morning, and a Wind Advisory is in
place.

Night through morning marine layer clouds will be common at times,
however offshore flow will limit marine keep clouds along the
Central Coast the next couple of nights. Sundowner winds will
likely keep marine layer clouds away from the Santa Barbara south
coast and potentially Ventura County.

.LONG TERM (WED-SAT)...12/1243 PM.

Little change expected Tuesday-Wednesday with a fairly stagnant
upper pattern and persistent moderate to strong onshore flow.
There may be slight cooling each day, but the fairly mild mid-
September should continue. The marine layer will likely become
more robust across all coasts and maybe some lower valleys.

The consensus in models for Thursday through the end of next week
is for warming, as high pressure builds in from the southeast and
onshore flow weakens. The magnitude of that building high
pressure and the offshore trends are still to be settled, which
means the magnitude of the warming is uncertain. Temperatures
pushing above normal look very likely, with a low but non-zero
chance of Heat Hazard-level hotness. Peering down to the south,
there are a couple of tropical systems that could provide some
moisture, but the signal is weak at this point.

&&

.AVIATION...13/0049Z.

At 2351Z at KLAX, the marine layer was 1400 feet deep. The top of
the inversion was at 3400 feet with a temperature of 24 degrees
Celsius.

For the 00Z TAF package, high confidence in CAVU conditions for
KPRB, KSBA, KWJF and KPMD.

For all other sites, low to moderate confidence due to uncertainties
in marine layer cloud coverage overnight. There is a 40% chance
of MVFR/IFR conditions at KSBP, KOXR and KCMA 08Z-15Z. For KBUR
and KVNY there is a 30-40% chance that no CIGs occur, or that CIGs
appear briefly or intermittently. For the LA Basin TAFs, timing
of flight category changes could be +/- 3 hours of current
forecasts.

KLAX...Low to moderate confidence in the 00Z TAF. The timing of
MVFR conditions could be +/- 3 hours of current forecast of
09Z-17Z. CIGs could be brief or intermittent. No significant
easterly wind component is expected.

KBUR...Low confidence in the 00Z TAF. The timing of CIG/VSBY
restrictions could be +/- 3 hours of current 09Z-16Z forecast.
There is a 30-40% chance that no CIGs occur.

&&

.MARINE...12/639 PM.

High confidence in current suite of Small Craft Advisories (SCA)
and Gale Warnings (GLW). Gale Force winds are expected for all
outer waters through Sunday night, with Sunday afternoon and
evening likely the strongest. Gale conditions may linger into
Monday morning, with moderate confidence that SCA winds will
linger into late Monday night or early Tuesday morning. Strong
SCA winds will reach into the nearshore waters along the Central
coast and Santa Barbara Channel through the weekend. These winds
will generate a building short-period fresh swell over all waters,
peaking in the afternoon & evening hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 6 AM PDT Monday for zones
      349-351-352. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 11 PM PDT this evening
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Sunday for zone
      650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 PM PDT this evening
      for zones 670-673-676. (See LAXMWWLOX).
     Gale Warning in effect until 6 AM PDT Monday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Lewis/Ciliberti
AVIATION...Ciliberti
MARINE...DB/RK
SYNOPSIS...RK/BL/CC

weather.gov/losangeles

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