385
FXUS66 KLOX 021138
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
438 AM PDT Sun Jun 2 2024

.SYNOPSIS...02/332 AM.

Temperatures cooler than normal will linger today due to strong
onshore flow and a persistent marine layer. A warming trend will
establish through Thursday due to high pressure aloft building in
and weakening onshore flow. The warming trend will be most
pronounced away the coast into the interior valleys. Closer to
the coast, night through morning low clouds and fog with persist
with moderate to strong onshore flow continuing. Clouds may
continue to struggle to clear from the beaches.

&&

.SHORT TERM (TDY-TUE)...02/438 AM.

The latest satellite imagery indicates low clouds and fog pushing
well into the coastal slopes of the mountains early this morning
as strong onshore flow and a persistent deep marine layer depth
remain in place. An eddy circulation continues to spin just
northwest of Santa Catalina Island, deepening the marine layer
depth to between 3000 and 3500 feet deep south of Point
Conception. To the north, the marine layer depth is closer to
around 2000 feet deep this morning as clouds are pushing into the
interior valleys of San Luis Obispo County. Patchy drizzle is
possible this morning and there is a good chance that an update
will issued to the forecast as some rain gages are starting to
pickup drizzle and ceilings at area airports are falling
slightly. A cooler weather pattern will linger today across much
of the coastal and valley areas, and these areas are likely below
to slightly below normal. Across the interior, temperatures will
start to warm as downsloping effects continue and onshore flow
starts to wane.

Gusty Sundowner winds are weakening across southern Santa Barbara
County this morning, but the northerly surface pressure gradient
will tighten over the coming days, potentially bringing another
couple rounds of Sundowner winds. With the gradient progged to be
slightly weaker today, wind advisory headlines were tabled for
this afternoon and tonight, but the gradient will tighten on
Monday night and could bring another round of advisory level
Sundowner winds. Gusty northerly winds will also develop through
the Interstate 5 Corridor and a wind advisory will likely be
needed for this area, as well. Marginally gusty winds could
possibly also extend into portions of the far western Antelope
Valley.

A warming trend will take shape over the coming days as 500 mb
heights climb. The developing northerly surface pressure gradient
and climbing heights will weaken the onshore push each day and
thin the marine layer depth some. The warming trend will become
more pronounced between Tuesday and Wednesday across the interior
portions as hot temperatures will develop across interior valleys
and adjacent foothills, but closer to the coast, a persistent
moderate to strong onshore push will remain and keep the warming
trend more moderate along the coast. The likely scenario will be
for a June Gloom pattern to keep low clouds and fog hugging the
beaches each afternoon, then the clouds will push back in during
the evening.

.LONG TERM (WED-SAT)...02/437 AM.

Temperatures will warm closer to critical levels for excessive
heat across the Antelope and San Luis Obispo Interior Valleys on
Wednesday. NBM solutions are suggesting a greater than 95 percent
chance of 100 degree high temperatures for KPMD and KWJF on
Wednesday, and high chance of temperatures reaching 105 degrees.
Chances for very hot temperatures are lower elsewhere but still
near excessive criteria across the Carrizo Plain. Given it will be
a close call, an excessive watch was added for Wednesday
afternoon and evening for Antelope and San Luis Obispo Interior
Valleys and adjacent foothill areas to highlight the potential for
excessive heat. As it is a marginal case, it would not be
surprising to see the watch either dropped or converted to an
advisory or warning. With the southeast flow aloft developing with
the ridge building into southeast California, it is possible that
this watch could also be extended into Thursday.

There is good amount of uncertainty for Thursday and Friday as EPS
and GEFS solutions offer up quite a bit of spread for high
temperatures. The chances for 100 degree temperatures fall in NBM
solutions into Thursday. There is a low chance that an early
start to the Southwest Desert Monsoon could develop across
southern California. This could cut into temperatures by
increasing cloud cover across these areas. In hinting at the
possibility, EPS cloud cover means do increase some between
Thursday afternoon and into next weekend.

With the ambient southeast flow aloft, PoPs and chance for
thunderstorms are non-zero for Thursday and Friday, but PoPs
still remain below mentionable levels during the afternoon and
evening. Pattern recognition would suggest the pattern consistent
with the monsoon developing but forecast ensemble and
deterministic solutions do not have a good handle on it. Stay
tuned for updates on this.

A cooling trend should develop for next weekend as troughing digs
into the region.

&&

.AVIATION...01/2309Z.

At 2215Z at KLAX, the marine layer was 2600 ft deep. The top of
the inversion was at 4800 feet with a temperature of 20 deg C.

Overall, moderate to high confidence in 00Z TAF package. High
confidence in return of CIG/VSBY restrictions to all coastal and
valley sites, but only moderate confidence in timing of flight
category changes (could be +/- 2 hours of current forecasts).

KLAX...Moderate confidence in 00Z TAF. There is a 40% chance that
IFR conditions will not develop overnight. 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. Timing of flight category
changes could be +/- 2 hours of current forecasts.

&&

.MARINE...01/836 PM.

In the northern outer waters zone (PZZ670), Gale Force winds will
continue tonight. Then, SCA conds are expected (80% chance) late
tonight thru Tue. There is a 40% chance gales Sun afternoon/eve.
There is a 50% chance of SCA conds Tue night/Wed morning. Conds
should then be below SCA levels Wed afternoon through Thu.

In the southern two outer waters zones, (PZZ673/676), SCA conds
will likely continue through at least late Monday night or
Tuesday. Conds should then be below SCA levels late Tue night
through Thu.

In the inner waters N of Pt. Sal, SCA level winds are likely (70%
chance) during the afternoon/eve hours today thru Mon and possible
thru Tue. Conds will then be below SCA levels Tue night through
Thu.

In the inner waters S of Pt. Sal, there is a 60% chance of SCA
winds in western portion of the SBA Channel during the afternoon
and evening hours through Mon. Otherwise, conds over the inner
waters should be below SCA levels thru Thu.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Watch in effect from Wednesday morning through
      Wednesday evening for zones 344-381>383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 645-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zones 670-673. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Monday for zones 670-673. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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