809
FXUS66 KLOX 010331
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
831 PM PDT Fri May 31 2024

.SYNOPSIS...31/817 PM.

A cooler than normal weather pattern will continue across much of
the area through the weekend as a persistent marine layer remains
in place with strong onshore flow. A warming trend is expected
next week, especially for the interior portions of the area
Wednesday and Thursday as onshore flow weakens.

&&

.SHORT TERM (FRI-MON)...31/829 PM.

Another warm day across the interior, with some of the warmest
locations (including Antelope Valley and Paso Robles) climbing
into the lower to mid 90s. A weak upper level trough across the
region combined with a strong onshore flow pattern near the
surface will bring a deepening marine layer trend. As of 8 pm,
satellite imagery showing a rapid surge of low clouds into coastal
and coastal valley locations. Current ACARS data showing the
marine layer depth around 2000 feet this evening across the LA
Basin so we will likely see low clouds spreading into some of the
interior valleys overnight. This will also lead to a few degrees
of cooling for most areas on Saturday/Sunday. The LAX-DAG
gradient peaked at around +9 mb this afternoon, with similar
gradients expected through Monday. Onshore wind gusts between
25 and 35 mph have been common this afternoon/evening across
the interior, with local gusts to 45 mph in the Antelope Valley
foothills. Similar onshore wind gusts are expected through the
weekend.

*** From previous discussion ***

A few degrees of warming and slightly earlier marine layer
clearing are likely Sunday and Monday as the trough starts to
shift east and high pressure begins to assert itself over the
west. Still below normal temperatures for coast/valleys but not as
much so.

.LONG TERM (TUE-FRI)...31/230 PM.

High pressure will be building over the western states starting
Tuesday and lasting through Wednesday and possibly Thursday before
another trough of low pressure returns for later next week into
next weekend. The warmup will be brief, and mostly confined to
the interior areas, but will likely result in our first 100
degrees readings in quite some time. Based on all the ensemble
runs from the NAEFS and EPS there is a greater than 80% chance of
100 degree or higher temperatures in the Antelope Valley on
Wednesday with lower chances Tuesday and Thursday. Similar chances
for far interior SLO County.

Closer to the coast it`s a much different story. Though warming is
expected for all areas, the amount of warming will be much more
moderate, and for coastal areas high will likely only top out in
the lower 70s at most with some beaches staying cloudy much of the
day. Onshore flow is expected to weaken and be at its lowest point
Tuesday and Wednesday but SST`s are still only around 60 which
will keep temps from warming up too much. Ensembles still indicating
around 60% chance of low 90s in the warmer valley areas like
Woodland Hills Wednesday, but likely in the mid to high 80s
otherwise.

Troughing returns later next week into next weekend for a likely
return of June gloom conditions and well below normal
temperatures for coast and valleys.

&&

.AVIATION...31/2323Z.

At 2230Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was at 5200 feet with a temperature of 21 deg C.

For the 00Z TAF package, high confidence in deserts TAFs as well
as KPRB. For other TAF sites (coastal and coastal valley),
moderate confidence in TAFs. High confidence in return of CIG and
VSBY restrictions for coastal and coastal valley sites, but low to
moderate confidence in timing of flight category changes.

KLAX...Moderate confidence in 00Z TAF. High confidence in CIG/VSBY
restrictions, but moderate confidence in timing of flight category
changes (could be +/- 2 hours of current forecasts). No significant
easterly wind component is expected.

KBUR...Moderate confidence in 00Z TAF. High confidence in return
of CIG/VSBY restrictions, but moderate confidence in timing of
flight category changes (could be +/- 2 hours of current
forecasts).

&&

.MARINE...31/815 PM.

In the northern outer waters zone (PZZ670), SCA winds are
expected to continue through at least Sunday night. Elsewhere in
the outer waters, winds and seas are expected to remain below SCA
levels thru Saturday morning. SCA level winds are likely (70%
chance) in zones 673/676 by starting Saturday afternoon and
continue through at least Sunday night. SCA conds are likely (70%
chance) in all the outer waters Mon and Monday night before
gradually subsiding Tuesday. Conds will likely be below SCA levels
for Wed.

In the inner waters N of Pt. Sal, there is a 30% chance of SCA
level winds Saturday afternoon. SCA conds are likely (60-70%
chance) during the afternoon/eve hours Sun through Mon. Conds
should then be generally below SCA levels Tuesday and Wednesday.

In the inner waters S of Pt. Sal, there is a 40% chance of SCA
winds in western portion of the SBA Channel during the afternoon
and evening hours Saturday through Sunday. Otherwise, conds over
the inner waters should be below SCA levels through Wednesday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Monday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 2 PM Saturday to 3 AM PDT
      Monday for zone 673. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/MW
AVIATION...RAT
MARINE...Gomberg/Sirard
SYNOPSIS...Hall

weather.gov/losangeles

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