Sun Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

628
FXUS66 KLOX 190344
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
844 PM PDT Wed Jun 18 2025

.SYNOPSIS...18/842 PM.

A cooling trend will take shape through Friday as an upper-level
trough of low pressure moves over the Pacific Northwest. Broad
troughing will linger into the middle portion of next week and
keep a persistent marine layer depth in place. Night through
morning low clouds and fog will become a staple of the forecast
period, struggling to clear from the coast at times. Gusty
northerly winds are expected to develop for late week across
southern Santa Barbara County and through the Interstate 5
Corridor.

&&

.SHORT TERM (WED-SAT)...18/842 PM.

Southwest flow aloft is continuing to strengthen this evening as
an upper-level ridge of high pressure pushes east and an upper-
level trough digs into the Pacific Northwest. Onshore flow will
strengthen over the coming days as southwest flow increases.
Night through morning low clouds and fog will reestablish over the
coming days and become a staple of the forecast.

An eddy circulation is developing across the southern California
bight this evening and the low cloud field is alluding to the low
clouds and fog becoming more entrenched overnight and into
Thursday morning. A few tweaks to the marine layer induced low
clouds and fog were made to the forecast through Thursday night,
but overall, the general idea is the same.

A tightening northerly pressure gradients will redevelop on
Thursday night and tighten each night through Saturday. Gusty
Sundowner winds will develop across southern Santa Barbara County
on Thursday afternoon and evening, then the pattern will likely
strengthen further on Friday and Saturday.

***From Previous Discussion***

A late season trough will push into northern California bringing
the relief from the heat as well as unseasonably strong northwest
to west winds across the region by Friday with widespread advisory
level (gusts 30 to 50 mph) winds possible, including many coastal
areas, especially from The Ventura County and points north.
Isolated warning level gusts around 60 mph will be possible for
the interior mountains, especially near the I-5 corridor and for
the Santa Ynez mountains, especially west of San Marcos Pass.
Isolated power outages, downed trees, and increased risk for large
wildfires possible with the strong winds. A wind advisory has
been issued for Thursday through early Friday for southwest Santa
Barbara County with additional advisories likely as we near the
event.

A deepening marine layer will enhance cooling to coastal areas,
bring more widespread low clouds and fog and patchy drizzle
(focused during the morning hours), especially for Los Angeles
County and the Central Coast.

.LONG TERM (SUN-WED)...18/221 PM.

The gusty northwest winds will likely continue into Saturday with
similar concerns to Friday before weakening significantly into
Sunday with further weakening into Monday. Weak troughing will
likely remain in place Sunday through at least Tuesday, supporting
below normal temperatures with seasonably weak onshore winds and
a fairly deep marine layer with night to morning low clouds and
fog. Patchy drizzle will again be possible, especially Saturday
morning as the trough passes just to our north.

&&

.AVIATION...18/2322Z.

At 2239Z at KLAX, the marine layer was 500 feet deep. The top of
the inversion was 3800 feet with a maximum temperature of 30 C.

High confidence in TAFs for KPRB, KPMD, and KWJF.

Moderate to low confidence in TAFs for KBUR and KVNY. There is a
30% chance for IFR to MVFR between 09Z and 17Z.

Low confidence in remaining TAFs. Timing of cig/vsby restrictions
may be off +/- 2 hours and flight cat minimums off by one. There
is a 20% chance of LIFR at KSMX from 08Z to 16Z Thu. There is a
30-40% chance of IFR conds at KSMO for same timeframe.

KLAX...Low confidence in 00Z TAF. Cig arrival and departure times
may be off +/- 2 hours, with a 30-40% chance of IFR cigs 005-009.
No significant wind issues expected through the forecast period.

KBUR...Low to moderate confidence in 00Z TAF. There is a 30%
chance for cigs (005-012) between 09Z and 17Z. If cigs do arrive,
there is a 10% chance of LIFR conditions.

&&

.MARINE...18/502 PM.

High confidence in widespread Small Craft Advisory (SCA) to Gale
Force winds and steep, choppy seas for the Outer Waters and
portions of the Inner Waters through Saturday night, with SCA
winds and seas lingering into Sunday evening. While confidence is
high that Gale Force winds will impact nearshore waters along the
Central Coast, there is also a moderate chance for Gale Force
winds to reach nearshore beaches from Ventura Harbor south to
Point Mugu Thursday through Saturday in the afternoon through
evening hours, with best chances Friday and Saturday.

The Inner Waters off the Los Angeles and Orange County coasts
will see SCA level wind gusts in areas such as Malibu, the San
Pedro Channel, and the Western portion of the zone Thursday
through Saturday, with better chances Friday and Saturday. There
is a 30% chance of SCA level seas for SW portions of PZZ655 Friday
evening into the overnight hours. Otherwise, seas are expected to
remain below SCA criteria.

Sub-advisory conditions look to kick off the early part of next
week across the entire coastal waters.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 4 PM Thursday to 9 AM PDT Friday
      for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Thursday for
      zones 645-673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM Thursday to 3 AM PDT Friday
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM to 6 PM PDT Thursday
      for zone 650. (See LAXMWWLOX).
     Gale Warning in effect from 6 PM Thursday to midnight PDT
      Thursday night for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Sunday for zone 670. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM Thursday to 3 AM PDT Sunday
      for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall/Munroe
AVIATION...Black
MARINE...Lewis/Black
SYNOPSIS...Hall

weather.gov/losangeles

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