211
FXUS66 KLOX 171754
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1054 AM PDT Thu Sep 17 2026

.SYNOPSIS...17/907 AM.

Generally quiet weather expected with cooler than normal
temperatures and a deep marine layer today. Slight warming and a
shrinking marine layer are expected Friday into the weekend.

&&

.SHORT TERM (TDY-SAT)...17/917 AM.

***UPDATE***

The marine layer depth based on pilot reports across the LA Basin
is a robust 5300 feet this morning. However, a reverse clearing
trend is already in progress with significant clearing already
ongoing across the LA Basin. The VBG sounding measured a similar
depth there as well but clearing is a little slower there south of
Morro Bay.

This is a result of a 568dam low over northern California. Models
indicate that this low will lift out Friday and Saturday with weak
ridging that will lead to lowering marine layer and modest
warming over the weekend.

***From Previous Discussion***

Not much to talk about as the weather for the next three days will
be very unremarkable. The only real thing of note is that the
weather is not very "September-like" at all.

Today and Friday will feature SW slightly cyclonic flow from an
upper low moving through far northern CA. Hgts will be near 586
dam today and then rise to 588 dam on Friday. Moderate onshore
flow will continue to the east. There will be weak offshore flow
in the N/S direction in the morning, but it will switch to weak
onshore in the afternoon. A very deep marine layer will continue
today with plenty of stratus covering the csts and vlys. The lack
of an eddy and the offshore push from the north will reduce the
amount of marine layer stratus coverage Friday morning. Today`s
max temps will be very similar to Wednesday`s and will run 5 to 10
degrees blo normal. Friday will see 3 to 6 degrees of warming
which will result in coastal highs in the 70s with 80s in the
vlys.

A little pop up ridge is set to move over the state on Saturday.
Offshore trends and increased hgts will further reduce the morning
low clouds. More sunshine, less onshore flow and higher hgts will
all combine to boost max temps by 2 to 5 degrees. Despite the
warming most max temps will still be 2 to 4 degrees under normals.

.LONG TERM (SUN-WED)...17/249 AM.

All mdls continue to advertise a high hgt (578 dam) dry upper low
passage for Sunday and Monday. The most likely outcome for this
passage will be an increase in marine layer stratus and 2 to 3
degrees of cooling each day. There is a 5 to 10 percent chc that
the system could find enough moisture to produce some mtn
convection, but this scenario is only seen by a scant few of the
ensembles. If any precipitation does occur it is very most likely
only to be morning drizzle.

Srn CA will be sandwiched in between a large upper low off the WA
cst and an upper high over TX. Hgts will end up around 587 dam.
The onshore flow is forecast to weaken some and this should kick
off a two day warming trend with most sites seeing 3 to 6 degrees
of warming each day. This warm up should bring most max temps up
to seasonal normals by Wednesday.

&&

.AVIATION...17/1753Z.

At 1716Z at KLAX, the marine layer was 3900 feet deep. The top of
the inversion was at 5800 feet with a temperature of 16 C.

High confidence in TAFs for KPMD and KWJF.

Moderate confidence in remaining sites. MVFR to VFR cigs should
burn off by 20Z. There is a 30% for MVFR cigs at KSBA after 15Z.
30% chance for no cigs at KOXR, KCMA, KVNY, and KBUR tonight. 10%
chance for LIFR conds at KPRB/KSBP/KSMX late tonight.

KLAX...Moderate confidence in TAF. Cigs may vary between 025 and
035 through 20Z. BKN035 conds may persist through 00Z. Return of
MVFR cigs tonight likely between 07Z and 13Z. Good confidence
that any east wind component tonight will remain below 8 kt.

KBUR...Moderate confidence in TAF. Cigs may vary between 025 and
035 through 20Z. BKN035 conds may persist through 00Z. 30% chance
for no cigs tonight.

&&

.MARINE...17/835 AM.

Moderate confidence in fairly typical Small Craft Advisory (SCA)
northwest winds developing across the outer waters this afternoon
and evening focused south and west of Point Sal, then higher
confidence in more widespread SCA winds Friday through Sunday
across the outer waters and nearshore waters along the Central
Coast. Choppy, short period seas will develop.

SCA winds will likely remain confined to the western portions of
the Santa Barbara Channel this afternoon and evening, but moderate
confidence in SCA winds spreading to eastern portions Friday
through Sunday (in the afternoon/evenings). Local gusts near 20
knot will be common each afternoon and evening through the San
Pedro Channel and Santa Monica Bay.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Saturday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Rorke
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...MW/Lewis

weather.gov/losangeles

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