Thousand Oaks, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

249
FXUS66 KLOX 141201
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
501 AM PDT Mon Apr 14 2025

.SYNOPSIS...14/455 AM.

A deep marine layer depth with strong onshore flow will continue
a cooling trend through the work week. Night through morning low
clouds and fog can be expected with drizzle possible each night
and morning. A cold upper level low pressure system is forecast
to bring showers to the area between Thursday night and Friday
night. A thunderstorm cannot be ruled out especially in the
mountains and deserts on Friday. Dry and milder conditions with a
warming trend can then be expected for next weekend.

&&

.SHORT TERM (TDY-WED)...14/500 AM.

Low clouds and fog are well entrenched across the region this
morning as broad upper-level troughing is anchored off the
California coast. Morning drizzle is starting to occur across
portions of the area as upper-level dynamics start to move over
the region. Two cutoff troughs can been seen on satellite imagery
this morning with one trough sitting about 230 miles west-
southwest of Point Conception, and another cutoff low sitting
about 500 miles south-southwest of Point Conception. Both troughs,
rotating around each other in a Fujiwhara effect, will continue
to provide a cooler weather pattern with a deep marine layer and a
threat of night through morning drizzle through tonight.

The southern trough will eject out of the broader circulation
late this afternoon and this evening across Baja California and
into southern California. Then, another trough near 37N and 137W
will drop in and merge with the northern trough, deepenening it as
it approaches the California coast on Wednesday. A cooler weather
pattern is likely to continue into late week, along with a deep
marine layer producing extensive low clouds and fog with night
through morning drizzle. Clearing will be inhibited along the
beaches each day as there is a high to likely chance that clouds
will hug the coast each day into Wednesday and maybe Thursday.

As the trough ejects out to the south of the area this afternoon
and evening, there is a non-zero chance of showers. Shower chances
could increase again on Wednesday as the deeper trough approaches
Point Conception. Quite a bit of dynamics and 500 mb heights
declining to 560 dam are certainly plausible to extend the night
through morning drizzle into later in the day or produce light
showers across the region. While PoPs remain lower than forecast,
moisture and precipitation parameterization schemes in the model
solutions typically struggle with trough circulations and dynamics
to the southwest of the region. NAM BUFR time height sections are
hinting at a deep enough marine layer by Wednesday morning to
turn the marine intrusion into a deep moist layer and continue
the possibility of light drizzle or rain. If NAM BUFR time height
sections are correct, the moist layer could deepen to near 7000
feet by Wednesday night across the Southland. This would be plenty
sufficient to produce showers or light rain.

.LONG TERM (THU-SUN)...14/458 AM.

The upper-level trough will drift over the Southland on Thursday
and bring the possibility of afternoon and evening showers and
thunderstorms. A cooling trend will continue into Thursday and
Friday as much colder air starts to pipe into the area as a trough
in the Gulf of Alaska will move over a ridge in the Pacific
Northwest and dig south down the leading edge. This could provide
an additional shot of colder air aloft to destabilize the air
mass for convective showers to develop. The two troughs will merge
at some point between Thursday and Friday with a colder air mass
being ushered in behind the trough for Friday. While the
instability looks to be best on Friday, showers and thunderstorms
cannot be ruled out on Thursday either.

Gusty winds are possible between Wednesday and Friday across the
Antelope Valley and across the interior portions of the region as
strong onshore pressure gradients approaching 10 mb onshore. EPS
ensemble members indicate gusty winds for KPMD and KWJF, albeit
just shy of advisory levels. Earlier ensemble wind gust means had
much stronger winds. Any change in the troughs direction could
result in much gustier winds across the region.

Cluster analysis continues to agree for a warming trend developing
over next weekend as an upper-level ridge over the North Central
Pacific Ocean will nose into the West Coast. While there are
variations to the ridge in the cluster analysis, all four WPC
clusters would suggest a warming trend developing. A thinner
marine intrusion should be expected with less low cloud coverage.

&&

.AVIATION...14/0017Z.

At 0010Z at KLAX, the marine layer was around 1500 feet deep. The
top of the inversion was around 2600 ft with a temp of 19 C.

Moderate confidence in all TAFs, except high confidence in desert
TAFs. Cigs likely to redevelop tonight across most coastal/valley
YAF sites except KPRB. Timing of flight cat changes may be off by
+/- 3 hours. Cigs may drop one flight cat lower than forecast
overnight.

KLAX...Moderate confidence in TAF. There is a 20% chc of LIFR
cigs tonight. Good confidence that any E wind component will
remain under 6 kt.

KBUR...Moderate confidence in TAF. There is a 30% chc that cigs
will arrive as early as 06Z Mon.

&&

.MARINE...13/753 PM.

Winds have subsided below Small Craft Advisory (SCA) levels,
however seas may linger around/just below 10 feet across the outer
waters into this evening. Otherwise, SCA conds are not expected
across all the coastal waters through Thursday night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Hall
AVIATION...Gomberg
MARINE...Lund
SYNOPSIS...Hall

weather.gov/losangeles

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