Area Forecast Discussion
Issued by NWS Los Angeles, CA

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740
FXUS66 KLOX 152017
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
117 PM PDT Tue Sep 15 2026

.SYNOPSIS...15/1157 AM.

Warm but below normal temperatures will continue through
Thursday, with expanding coastal morning low clouds. Temperatures
are likely to increase towards the end of the week.

&&

.SHORT TERM (TDY-THU)...15/1206 PM.

Deep marine layer influence well into the coastal foothills today
will expand further inland and upward into additional lower
mountain slopes and interior San Luis Obispo County into
Wednesday. Patchy drizzle is possible just about anywhere within
the mid level cloud deck early Wednesday morning. Fog may impact
lower mountain passes including lower portions of the I-5 corridor
as the low clouds deepen to between 3000-4500 feet. Reverse
clearing is likely where low clouds hang on longer coastal
valleys and especially foothills where a few spots may struggle to
clear much of the day.

A weak trough briefly stalling just north of San Fransisco and
the deepening marine layer will contribute to another few degrees
of cooling and breezy onshore winds for the far interior.

We enter a more progressive pattern Thursday and especially
beyond. The trough will slide east of the region by Friday with a
pop up ridge warming temperatures several degrees and approaching
normal by Friday or Saturday. The marine layer will shrink in
coverage and size and may undergo shrinking pains where it
struggles to reform, leading unexpectedly sunny skies sometime
Friday or Saturday.

.LONG TERM (FRI-MON)...15/1204 PM.

Not much going on in the xtnd very weak ridging moves into the
area Friday and continues into Saturday hgts may approach 588 dam.
Mdt onshore flow will continue to the east. There will be weak
offshore flow in the morning from the north but it will turn to
weak onshore flow in the afternoon. The morning offshore push
should reduce (but not eliminate) the morning low cloud coverage.
Look for 2 to 4 degrees of warming each day. This will lead to max
temps in the 70s and lower 80s across the csts and 80s in the
vlys on Saturday. Despite the warming these max temps are still 2
to 4 degrees blo normal.

A weak upper low will move into the area Sunday and Monday. It
currently looks to be moisture starved, although it should provide
sufficient dynamics to gin up a deep marine layer and perhaps some
morning drizzle or a passing shower.

Although the exact weather pattern becomes more uncertain, we have
fairly high confidence that benign weather will prevail into the
middle part of next week.

&&

.AVIATION...15/1728Z.

At 1701Z at KLAX, the marine layer was 3200 feet deep. The top of
the inversion was at 4500 feet with a temperature of 20 C.

High confidence a deep marine layer bringing low clouds to all
coastal and valley sites (10% chance at KPMD & KWJF). MVFR conds
will dominate south of Point Conception, with IFR to MVFR to the
north. There is a 15% chance of -DZ at any site with low clouds
late tonight into Wed morning.

North of Point Conception: 50% chance of no clearing today with
IFR-MVFR conds continuing at KSBP/KSMX. Low confidence in arrival
time (+/ 4 hours) and min cig height (+/- 500 ft) at KPRB
tonight.

South of Point Conception: 30% chance of no clearing today with
MVFR-VFR cigs continuing. Otherwise arrival times may be off +/- 3
hours and some sites may see cigs remain greater than BKN/OVC022
through the period.

KLAX...Moderate confidence in TAF except low confidence in
clearing this morning. There is a 30% chance for no clearing of
MVFR-VFR cigs, otherwise clearing time likely from now through
22Z. Cigs may remain above BKN/OVC022 through the period. Moderate
confidence in any east wind component remaining below 8 kt after
this morning and again late tonight.

KBUR...Moderate confidence in TAF except low confidence in
clearing this morning. There is a 30% chance for no clearing of
MVFR-VFR cigs, otherwise clearing time likely from now through
22Z.

&&

.MARINE...15/116 PM.

High confidence in relatively light winds over the area through
Thursday morning, with a return of normal outer waters (and
potentially Santa Barbara Channel) northwest Small Craft Advisory
(SCA) winds for Thursday night through the weekend. These winds
will generate a building short period swell over all waters. Best
chances for SCAs to be issued exist for the outer waters south and
west of Point Sal Thursday, then SCA winds are likely to become
more expansive Friday through this weekend.

&&

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

&&

$$

PUBLIC...RM/Rorke
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...RK

weather.gov/losangeles

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