073
FXUS66 KLOX 220245
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
745 PM PDT Sat Sep 21 2024

.SYNOPSIS...21/726 PM.

A warmer and drier pattern will establish through Monday as high
pressure aloft builds over the region. A warmer air mass will
likely remain in place through much of next week away from the
coast, with the hottest daytime temperatures forecast for Monday.
Onshore flow will persist through the period, maintaining night
through morning low clouds and fog for coastal areas and some of
the valleys.

&&

.SHORT TERM (SAT-TUE)...21/741 PM.

***UPDATE***

A quiet weather pattern is in store for Southwest California
through the short term, and into much of next week. Building high
pressure aloft will cause the marine layer to shrink somewhat
tonight into Sunday morning, with less extensive low clouds than
last night, and likely earlier clearing trends. Stratus tonight is
expected to move over the coastal areas and the coastal valleys,
and with weakening onshore flow, expect good clearing for all
areas in the afternoon. High temperatures will rise 6 to 12
degrees away from the coast compared to today`s highs, with 2 to
5 degrees of warming near the coast.

As the ridge aloft strengthens into Monday, the marine layer will
shrink further, with overnight low clouds confined to coastal
areas and temperatures will bump up another few degrees. Peak
highs on Monday will be in the mid 90s to around 100 degrees in
the warmest valleys.

***From Previous Discussion***

A slow clearing marine layer kept coast and valleys relatively
cool today, mostly 60s and 70s, while interior areas warmed up
considerably. At least some of that interior warming will migrate
towards the valleys and coast Sunday into next week as building
high pressure aloft and weakening onshore flow combine to
dramatically lower the marine layer depth. Highs Sunday expected
to rise 10 degrees over today across the valleys and 2-5 degrees
closer to the coast. The marine layer, which was 3000` this
morning south to 1000` north, is expected to be cut in half by
Sunday and Monday, resulting in much earlier clearing at least for
inland areas. Another 3-6 degrees of warming expected Monday
bringing warmest valley highs to the mid to high 90s, roughly 4-8
degrees above normal.

A slight increase in onshore flow is expected Tuesday afternoon
that will cool temperatures a couple degrees across coast and
valleys but either little change or slight warming across the
interior.

.LONG TERM (WED-SAT)...21/148 PM.

Overall very quiet weather expected across southwest California
the rest of next week with most of the ensemble based guidance
maintaining temperatures at near to slightly above normal through
the period. However, there is increasing spread in the ensemble
solutions later next week resulting is decreasing confidence in
the forecast. None of the solutions show rain south of the Bay
area, but there are some solutions with a deeper trough along the
West Coast Thu-Sat with cooler than normal temperatures.

&&

.AVIATION...22/0121Z.

At around 00Z at KLAX, the marine layer was about 1800 ft deep
with an inversion up to 4000 ft and a maximum temperature of 22 C.

High confidence in TAFs for KPRB, KPMD, and KWJF.

Moderate confidence for all coasts and valleys. Arrival and
clearing of cigs may be off by +/- 2 hours. Cigs may be off by 1
category at times, with periods of LIFR conditions possible for
coastal sites from 12Z-17Z. There is a 30% chance of no cigs for
KBUR and KVNY.

KLAX...Moderate confidence in TAF. Arrival and clearing of cigs
may be off by +/- 2 hours, and cigs may be off by 1 category at
times. No significant east wind component expected.

KBUR...Moderate confidence in TAF. Arrival and clearing of cigs
may be off by +/- 2 hours, and there is a 30% chance of no cigs at
all.

&&

.MARINE...21/117 PM.

For the Outer Waters (Central Coast south to San Nicolas
Island), moderate to high confidence in winds and seas remaining
below Small Craft Advisory (SCA) level thru Wednesday, except for
a 30-40% chance for low end SCA level wind gusts near Pt
Conception Sunday evening thru late night. Then there a 30-50%
chance of SCA level wind gusts beginning late Wednesday afternoon
and evening, then higher confidence for Thursday and Friday, which
will also lead to building steep seas.

For the inner waters along the Central coast, high confidence in
conds remaining below advisory levels through early Thursday, with
moderate confidence in increasing winds in the afternoon Thursday
and Friday.

For the Inner waters south of Point Conception, moderate to high
confidence in conditions remaining below SCA levels through
Wednesday. There is a 20-30% chance of local low end SCA gusts in
the far western portion of the Santa Barbara Channel and the San
Pedro Channel Sunday afternoon. Additionally, there is a 30-40%
chance of SCA level winds across the western portions Wednesday
thru Friday in the afternoon thru evening hours.

&&

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

&&

$$

PUBLIC...MW/Smith
AVIATION...Schoenfeld
MARINE...Lewis
SYNOPSIS...Smith

weather.gov/losangeles

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