227
FXUS66 KLOX 230811
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
111 AM PDT Sun Mar 23 2025

.SYNOPSIS...22/953 AM.

Dry and occasionally breezy conditions are expected through next
week. Temperatures will be near or slightly above normal today,
then a significant warmup is expected Sunday into Monday. High
temperatures on Monday will be well above normal, with
temperatures in the 90s across the warmest valleys of Los Angeles
and Ventura Counties. A cooling trend will start Tuesday with
temperatures closer to normal by Thursday.

&&

.SHORT TERM (TDY-TUE)...22/831 PM.

Much of the region is seeing partly cloudy skies tonight as a
result of an upper level trough to the north. A combination of
slightly stronger onshore flow and lowering 500 mb heights has
allowed temperatures today to be a few degrees cooler compared
to yesterday at most locations. A weak eddy circulation will
likely spin up some low clouds for the LA county coastal plain,
while moisture from the San Joaquin Valley will likely generate
low clouds across the interior valleys of San Luis Obispo County.
Latest HREF guidance trending slightly less probable of low
clouds moving up the coast into the Ventura county coastal plain
and Santa Barbara south coast.

A weak inside slider will move SE of the region tonight, turning
flow offshore and bringing some gusty winds this evening and
overnight from the N-NE for areas north of Point Conception and
NW-N for areas southward. The western Santa Barbara South Coast
and western Santa Ynez range have a wind advisory in effect for
these winds, with expected wind gusts of 40 to 50 mph. The gusty
sundowner winds are starting to spread eastward into the Montecito
Hills area where gusts of 35 to 45 mph have been observed. These
winds being generated by the Santa Barbara-Bakersfield gradient
of -4.2 mb. As a result, a wind advisory may need to be expanded
into the eastern Santa Ynez range. North to northeast wind
gusts of 25 to 40 mph will also be likely across the interior
mountains, the Santa Lucia Mountains, Santa Ynez Mountain Range,
as well as the western portion of the Antelope Valley
floor/foothills and I-5 Corridor. Brief isolated gusts of 40 to 50
mph will not be out of the question for the typical northerly
wind corridors.

*** From previous discussion ***

Along with the low clouds, lowering 500 mb heights (due to the
aforementioned inside slider) may result in some drizzle tonight
into tomorrow morning across the coastal areas where clouds do
form. Additionally, some moisture may bring drizzle to the
northern slopes of the interior mountains along the Kern County
line for the same time period.

As the inside slider moves away from the region, a
ridge will build in behind and turn flow more north-northeast due
to weakening onshore flow on Sunday. Due to the northerly offshore
flow and weakening onshore flow, low clouds will likely not last
long in the morning. These offshore trends combined with rising
500 mb heights from the strengthening upper level ridge will kick
off the warming trend, bringing 3 to 6 degrees of warming to
coasts/valleys and 4 to 8 degrees across the interior. While the
beaches will only see highs in the 60s, the rest of the
coasts/valleys will be in the 70s and lower 80s, with local mid
80s in the warmest valley locations.

High pressure will continue to build on Monday, making Sunday the
warmest day of the stretch and warmest day of the year so far. An
upper high will be in place over Southern California, resulting in
500 mb heights rising to 583 dam (about 10 dam higher than
normal). Just as important, offshore flow will develop from the
east while offshore flow from the north continues. While winds
will remain sub-advisory and be on the weaker side, the offshore
flow will contribute to the warming temperatures. Almost all
areas will warm by 5 to 10 degrees compared to Sunday. The coasts
will end up in the 70s and lower 80s (a few beaches will stay in
the upper 60s) and the warmest valleys will mostly be in the mid
80s to lower 90s. These temperatures will be 10 to 20 degrees
above normal. The most recent EC run does show temperatures being
a few degrees warmer than forecast on Monday and keeping
temperatures just as warm on Tuesday, but the rest of the guidance
remained on track. While the chances are still low, a heat
advisory or two may be needed if other guidance trends warmer like
the EC.

.LONG TERM (WED-SAT)...22/320 PM.

On Tuesday, the ridge breaks down and the offshore flow weakens.
This will bring 3 to 6 degrees of cooling to most of the area.
Max temps will remain well above normal. As previously mentioned,
the EC does limit the cooling of temperatures on Tuesday, but
until other guidance hops on the warmer trend, decided to keep
forecast as is.

Weak troffing will move over the southern half of the state on
Wednesday and onshore flow will increase. There is a chance that
some low clouds will develop but more likely they will hold off
until Thursday. There will probably be enough mid level clouds
moving overhead to make it a partly cloudy day. Max temps will
drop 5 to 10 degrees which will bring the coasts and lower valleys
to below normal, while the rest of the area will remain a few
degrees above normal.

An upper level low will move into the northern half of the state
on Thursday resulting in lowering heights and increasing cyclonic
flow. This will likely produce an abundance of coastal low clouds
as well as plenty of mid and high clouds. There is a less than 10
percent chance that SLO county may see some rain as the system
passes by. More cooling is on tap especially across the interior,
causing max temps to almost all end up below normal for this time
of year.

Not the best model agreement starting Friday, but the ensemble
consensus points to a decent marine layer stratus pattern and a
few more degrees of cooling. Out on the horizon, long range
models and ensembles have been hinting at a storm system for the
start of April. However, guidance continues to have a large
variety of outcomes ranging from no rain to moderate to heavy
rain. Stay tuned to the forecast as more details will be available
as we get closer.

&&

.AVIATION...23/0743Z.

At 0712 at KLAX, the marine inversion was 500 feet deep, with an
inversion up to 2300 feet with a temperature of 15 C.

Moderate confidence in coastal and valley TAFs from KSBA
southward with a 10-20 percent chance of MVFR/IFR cigs for
KBUR/KVNY/KSBA sometime between 10Z-17Z and a 30-40 percent
chance that VFR conditions prevail for KSMO/KOXR/KCMA. There is a
10-20 percent chance of DZ where low cigs do occur and timing of
cig arrivals may be off by 2 hours.

Moderate confidence for KPRB with low clouds likely sometime
10-18Z, but timing may be off by 2 hours and one flight category.

High confidence elsewhere.

KLAX...Moderate confidence in TAF. There is a 20% chance that VFR
conditions prevail through the period. Should low clouds occur,
timing may be off by 2+ hours, and may be as low as BKN006.

KBUR...Moderate to high confidence in TAF. There is a 10 percent
chance of brief BKN008-BKN015 cigs between 12-18Z.

&&

.MARINE...22/539 PM.

For the Outer waters, high confidence in widespread strong Small
Craft Advisory (SCA) to GALE conditions at times through late
tonight. The strongest winds are expected for the waters around
Pt. Conception, Northern Channel Islands, down to San Nicolas
Island (including western portions of PZZ676), and northern
portions of PZZ670. Patchy dense fog is possible overnight,
especially for the SBA Channel and the waters well offshore of
the Central Coast (PZZ670).

Thereafter, lingering SCA conds are expected through late
overnight Sunday. Conditions will remain below SCA levels Mon and
Tue, before returning as early as late Wednesday afternoon. SCA
level winds look to be widespread Thursday and Friday, with a
20-30% chance for GALES. Seas are also expected to reach SCA
levels during this timeframe, likely peaking in the 12-16 foot
range.

For the Inner waters, there is a 60% chance of SCA level winds in
PZZ645 tomorrow afternoon/eve. The strongest winds will likely be
across the waters around and to the south of Port San Luis. Conds
are generally expected to remain below SCA criteria Mon and Tue,
before returning as early as Wed lasting thru at least Fri. There
is a low chance (20-30%) of GALES Thu and Fri in PZZ645/650.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory now in effect until 6 AM PDT early this morning
      for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT early this
      morning for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 6 AM PDT early this
      morning for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT early this morning for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Lund
AVIATION...Schoenfeld
MARINE...Black
SYNOPSIS...JMB/KL

weather.gov/losangeles

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