681
FXUS66 KLOX 250351
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
851 PM PDT Thu Jul 24 2025

.SYNOPSIS...24/421 PM.

Night through morning low clouds and fog will continue to be a
staple of the forecast for most coast and some valley locations
through Sunday. Persistent onshore flow will remain in place
through the weekend over the California coast and keep an onshore
flow regime across the area. Temperatures will continue to be on
the cool side of seasonal normals into early next week, then a
warming trend should start to develop as onshore flow weakens.

&&

.SHORT TERM (THU-SUN)...24/850 PM.

***UPDATE***

The upper level low up north continues to support a deep marine
layer with clouds reaching far into interior San Luis Obispo
County, while at the same time, high pressure starts building in
from the south. This morning, satellite imagery showed
significantly less coverage of stratus for Ventura and LA
Counties. We should see a similar pattern overnight tonight, but heights
are trending lower south of Point Conception which means we could
see a bit more stratus tonight than last night. Breezy sundowner
winds have developed over western portions of the Santa Ynez
range, but are expected to stay below advisory levels tonight.
Temperatures look similar with minimal changes and the current
forecast looks on track.

***From Previous Discussion***

A few clouds linger along the beaches this afternoon, but mostly
clear skies prevail across the land mass today. Low clouds and
fog will return again tonight across most coastal and valley
areas as a persistent and deep marine layer depth remains in
place. Strong onshore flow is likely to persist through the
weekend as a weak upper-level trough of low pressure will linger
over the California coast into Sunday. Low clouds and fog are
expected to become well-entrenched tonight and into Friday morning
due to strong onshore flow. An eddy circulation in place across
the southern California bight this morning will likely reform and
strengthen overnight as a low-level northwest flow parallel to
the southern California coastline creates a conducive environment
for eddy generation. The marine layer depth near 1300 feet deep at
KLAX currently should deepen overnight to between 1600 and 2000
feet deep. As the trough axis approaches the coast on Saturday,
the marine layer depth should deepen additionally to between 2000
and 3000 feet deep. Patchy night through morning drizzle cannot be
ruled over as some weak instability is moving over the region
tonight and into Friday morning, and again Friday night and into
Saturday morning. With strong onshore flow and a persistent marine
layer depth in place, the air mass will continue to remain on the
cooler side of normal. A cooling trend should continue into
Saturday.

A low-level northwest flow pattern in place will enhance the
diurnal downslope wind regimes over the next couple of days.
Marginally strong Sundowner winds will develop each night,
potentially nearing advisory levels this evening across
southwestern Santa Barbara County. NAM-WRF surface pressure
gradients suggest KSBA-KSMX values to be on the weak side of
advisory criteria, while NAM BUFR time height sections indicate
wind maximums in the core of the Sundowner winds to be just shy of
advisory levels. Any issuance of a wind advisory will be tabled
for now. Local gusts to 45 mph may still occur this evening near
Gaviota, but the winds look to be shy of advisory levels.

Between Saturday and Sunday, the trough axis will move ashore and
the marine layer depth should start to shrink. The most notable
thinning of the marine layer depth is expected along the Central
Coast. Onshore flow should still remain intact and keep
temperatures below normal, but a warming trend will start to
develop, especially away from the coast.

.LONG TERM (MON-THU)...24/210 PM.

A warming trend will continue into much of next week as 500 mb
heights rise through the period. Cluster analysis hold on to an
upper-level trough to the northwest of the region, which should
allow for onshore flow to persist. Onshore pressure will be
weaker, but persistent night through morning low clouds and fog
are likely to persist across most coastal and some lower valley
areas. EPS ensemble members favor warming over the region,
especially away from the coast and into the interior valleys and
desert. A few degrees of warming will likely take shape each day.
Closer to the coast, onshore flow will likely keep the warming
trend more moderated.

A low-level northwest flow pattern is likely to persist with a
cooler air mass to the northwest and a warmer air mass over the
Desert Southwest region. The possibility of gusty Sundowner winds
will remain in the forecast each evening as a result.

&&

.AVIATION...25/0246Z.

At 2328Z at KLAX, the marine layer was around 1000 ft deep. The
top of the inversion was around 2900 feet with a temperature of
20 C.

High confidence in VFR TAFs for KWJF and KPMD.

Moderate to high confidence in TAFs for KPRB, KSBP, KSMX, and KSBA.
Lower confidence in remaining coastal sites. Arrival of cigs may
be off by +/- 2 hours. There is a chance for IFR cigs at KPRB,
KSBP, KCMA, KOXR, and KSMX after cigs arrive.

Moderate confidence in TAFs for KBUR and KVNY. There is a 10-20%
chance for IFR/MVFR cigs between 10Z and 16Z.

KLAX...Moderate confidence in TAF. Arrival of cigs tonight may be
as early as 08Z or as late as 13Z. Minimum cig height may be off
+/- 200 ft. Any east component wind between 08Z and 17Z should
remain below 6 kts.

KBUR...Moderate confidence in TAF. There is a 10-20% chance of
brief cigs around 11Z to 16Z.

&&

.MARINE...24/841 PM.

NW Small Craft Advisory (SCA) winds will impact the outer waters
south of Point Conception through the period, especially in the
afternoon and evening hours. Winds will increase to SCA levels for
the northern outer waters Sunday afternoon and continue through
the remainder of the period.

The inner waters along the central coast will see local SCA level
gusts in the afternoon and evening through Saturday, then SCA winds
will become more widespread Sunday through the period (50% chance
for SCA issuance each day).

For the Santa Barbara Channel, moderate to high confidence in SCA
level winds across most of the Channel through late night, and
high confidence in SCA winds returning Friday afternoon and night,
with a 40-50% chance for SCA level winds reaching nearshore from
Ventura Harbor south to Point Mugu. Then SCA level winds will
impact the western half of the Channel each afternoon/evening
through the period, with lower chances of winds reaching the
eastern portion.

For the inner waters off the coast of Los Angeles and Orange
Counties, SCA level WNW wind gusts affected areas around Point
Dume, across the Santa Monica Bay (including nearshore), the San
Pedro Channel, and south and west of Catalina Island. Another
round of weaker SCA level winds are possible Friday afternoon and
evening for a similar area (40% chance for an SCA issuance).
Thereafter, sub- advisory conditions are likely into next week.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Friday for zone
      650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Saturday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall
AVIATION...Phillips
MARINE...Lewis/Ciliberti
SYNOPSIS...Hall/Ciliberti

weather.gov/losangeles

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