Simi Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

978
FXUS66 KLOX 161109
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
309 AM PST Tue Dec 16 2025

.SYNOPSIS...16/159 AM.

Well above normal temperatures will continue through Friday, with
locally gusty north to northeast winds peaking Tuesday Night and
Wednesday. Dry conditions will continue at least through Saturday,
but there is growing potential for a winter storm next week.

&&

.SHORT TERM (TDY-THU)...16/235 AM.

Skies are mostly clear this morning save for coastal morning low
clouds and dense fog along the LA coast. Offshore flow from both
the N and E will produce locally gusty canyon winds this morning.
(side note: the Tule Fog in the San Joaquin Vly is likely
affecting the pressure at KBFL and this is producing higher than
normal offshore gradients from the north. This higher pressure,
however, does not seem to have the same effect on the winds that a
non Tule gradient of similar values produces) The offshore flow
will combine with much higher than normal hgts (588 dam or +17
dam over normal) to bring max temps in the mid 70s to mid 80s
across the csts and vlys. These max temps are generally 12 to 18
degrees above normal.

The offshore push to the west will weaken tonight and this will
allow a shallow marine cloud layer to develop across most of the
csts. Patchy dense fog will likely accompany the clouds since the
marine layer will likely be 500 ft or lower. A decent N to S push
will bring low clouds to the Paso Robles area. A decent push from
the north will combine with a little northerly upper support and
will bring gusty winds to the mtns and hier vlys. The winds could
reach advisory levels in the I-5 corridor.

The upper high will weaken a tad wednesday and hgts will fall to
about 585 dam. Enough mid and high clouds will advect into the
area to make it a partly cloudy day. The lower hgts, increased
cloud cover and weaker offshore flow to west will all combine to
lower temps by 2 to 4 degrees. The interior may cool more as the
north flow brings in cooler air from the interior.

The offshore flow form the east increases on Thursday and this
along with the continued offshore flow from the north will create
a weak Santa Ana. It does not look like it will produce advisory
level winds but it will keep the low clouds away and allow 2 to 4
degrees of warming which once again will bring max temps that are
12 to 18 degrees above normal to the forecast area.

.LONG TERM (FRI-MON)...16/246 AM.

The offshore flow ends pretty quickly Friday into Saturday and
onshore flow increases on Sunday. At the upper levels the large
upper high will be pushed to the south and westerly flow will set
up over the state. Hgts will fall through the period and end up
around 579 dam. The marine layer will be pretty wiped out Friday
but will reform by Saturday morning when plenty of coastal low
clouds are forecast in the morning. By Sunday mostly cloudy skies
will move over the area as they advect in with the westerly flow.
Max temps will fall each of the three days and by Sunday max temps
will end up mostly in the mid 60s to mid 70s across the csts/vlys.
Despite all of the cooling max temps will be above normal all
three days.

All eyes on next week as the both the EC-AI and GFS-AI mdl
continue to show a period of storminess developing. The GFS is
faster than the EC. Exact timing and details are still quite
murky but there is a chc of rain each day Mon through Fri (this is
a result of many different mdl solutions the actual period of rain
will likely be 2 or 2 and half days south of Pt Conception and 3
or 3 and half days for the Central Coast). Some solutions are
quite wet so people with travel plans should keep an eye on this
developing forecast. One thing is fairly certain: this will not
be a snow maker as the flow is from the south which will keep the
snow levels well above the major passes.

&&

.AVIATION...16/1104Z.

Around 10Z, the marine layer was around 400 feet deep at KLAX.

High confidence in the current forecast, except moderate
confidence in the current forecast for coastal terminals from
KOXR southward.

VFR conditions are expected through the period, except for a high
to likely chance of VLIFR to LIFR conditions at coastal terminals
south of KOXR through 16Z, and again after 08Z Wednesday.

KLAX...There is a 60 percent chance of VLIFR to LIFR conditions
through at least 16Z. VFR conditions could develop as soon as 15Z
or late as 1730Z. There is a 10 percent chance of MVFR
visibilities lingering until as late as 22Z. Any easterly winds
should remain less than 7 knots.

KBUR...VFR conditions are expected through the period. No wind
impacts are expected at this time.

&&

.MARINE...16/304 AM.

High confidence in the current forecast through Thursday, then
moderate to high confidence thereafter.

For the waters southwest through northwest of the Channel Islands
and the nearshore waters along the Central Coast, there is a 50-80
percent chance of Small Craft Advisory (SCA) level winds through
Friday, highest during the afternoon and evening hours. There is a
30-40 percent chance of widespread GALES each afternoon and
evening through Wednesday night, but local GALE force gusts are
possible each afternoon and evening from Point Conception south to
San Nicolas Island. Winds will likely diminish some for Thursday
and Friday with chances of SCA level winds decreasing to a 40-70
percent chance, highest Point Conception south to San Nicolas
Island, but seas will approach SCA levels for late week.

Inside the southern California bight, winds and seas will remain
below SCA levels through Wednesday, but there is a moderate (30-40
percent) chance of SCA level winds across the western portions.
Winds  will increase on Wednesday with chances for SCA level
winds increasing to a high (40-50 percent) chance. Gusty north to
northeast winds reaching SCA levels are possible nearshore on
Wednesday night and into Thursday morning. Winds and seas should
drop below SCA levels for Friday and Saturday.

A shallow marine layer depth across the inner and southern coastal
waters will bring areas of dense fog this morning and potentially
lingering through Wednesday morning at times.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 10 AM PST this morning for
      zones 342-345. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from noon today to 9 PM PST
      this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Thursday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Hall
MARINE...Hall
SYNOPSIS...RK/Ciliberti

weather.gov/losangeles

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