003
FXUS66 KLOX 031634
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
934 AM PDT Mon Jun 3 2024

.SYNOPSIS...03/522 AM.

A warming trend will establish through Wednesday due to high
pressure aloft building in and weakening onshore flow. The warming
trend will be most pronounced away the coast. Hot weather will
develop across the interior for much of this week with
temperatures much above normal for this time of year. Closer to
the coast, the warming trend will be moderated due to continued
night through morning low clouds and fog and moderate to strong
onshore flow.

&&

.SHORT TERM (TDY-WED)...03/858 AM.

***UPDATE***

The marine inversion early this morning ranged from near 1000 ft
deep at VBG to near 2700 ft deep at LAX. Low clouds and patchy
dense fog covered much of the Central Coast this morning but were
already starting to dissipate. S of Point Conception, the low
clouds were mostly over the L.A. County coast, vlys and lower
coastal slopes. However, the low clouds, which were fairly sparse
over VTU County early this morning have expanded some over the
coast and vlys before mid morning. The low clouds were also
expanding into the eastern portion of the S SBA County coast as
well. All the low clouds are expected to clear back to or off the
coast by early this afternoon, with some low clouds possibly
lingering at the SBA County Central Coast beaches. In addition,
there should be a fair amount of hi clouds moving into the
forecast area from the N thru this afternoon.

Through this afternoon and evening, strong and gusty NW to N
winds will affect the northern VTU County mtns to the I-5 Corridor
and into the Antelope Vly and foothills, particularly the west
side. Gusts up to 45 to 50 mph will be possible, and Wind
Advisories are in effect for these areas. Strong and gusty NW to N
winds are also expected to affect SW SBA County this evening, and
Wind Advisories are in effect for these areas as well. Elsewhere
in the foothills and mtns and along the Central Coast, gusty sub-
Advisory level NW to N winds can be expected this afternoon into
this evening.

Temps will turn several degrees warmer than yesterday for many
areas, with afternoon highs a few degrees above normal for much of
SLO/SBA Counties and into the Antelope Vly, but remain a few
degrees below normal elsewhere. Highs in the in the inland coast,
vlys and lower mtns will range from the mid 70s to mid 80s over
SLO/SBA Counties to the 70s to around 80 for VTU/L.A. Counties,
except in the upper 80s to lower 90s in the lower mtns and
Antelope Vly.

***From Previous Discussion***

West to northwest winds will develop across southwestern Santa
Barbara County, through the Interstate 5 Corridor, and down into
the western portion of the Antelope Valley through this afternoon.
Then, the winds will turn more northerly and affect the
southeastern portion of Santa Barbara County. Wind advisories
remain in effect for southwestern Santa Barbara County, the
Interstate 5 Corridor, and the western Antelope Valley foothills
for portions of today and tonight, but wind advisories were
expanded into the northern Ventura County mountains for today and
tonight and into the southeastern Santa Barbara County tonight.
There is a moderate to high chance gusty west to northwest winds
reaching advisory levels along the Central Coast and into the
Santa Ynez Valley, through the backcountry portion of the Santa
Barbara County mountains, and across the Antelope Valley floor
west of Highway 14.

Troughing to the north of the area will send quite a bit of middle
and high level cloudiness over the area through Tuesday. The
forecast keep a partly to mostly cloudy stance outside of the
marine layer depth due to the amount of cloudiness pushing south.
Adding confidence to the scenario, a look of infrared imagery
indicates a decent amount of cloudiness moving south this morning
across northern California.

Despite a thinning marine layer depth due to the ridge and the
northerly surface pressure gradient in place this morning, there
is a still a threat of a drizzle. Local 3-km WRF solutions
maintain a favorable flow pattern this morning and Tuesday morning
with weak omega values through the mixed layer. As far as this
morning, though rare, there have been times where ridging aloft
will clamp down on the dense marine air mass and will squeeze out
drizzle. As we move into Tuesday morning, the drizzle makes more
sense conceptually as the dynamics with the trough will lift the
low cloud deck and squeeze out drizzle.

High pressure should start to take control of the pattern on
Tuesday as the trough vacates the region and retreats south of
the U.S. border off the coast of Baja California. High pressure
aloft will build into the region, weakening onshore flow, and
thinning the marine layer depth. The air mass will heat up outside
of the depth of marine layer. A significant warming trend is
forecast for the interior portions of the area between Tuesday and
Wednesday, but the warming trend is more muted along the coast.
Still, there is a moderate chance that low clouds and fog could
get wiped out along the Central Coast between Tuesday and
Wednesday as enough offshore flow could develop. South of Point
Conception, confidence remains high that the marine influence will
remain wedged in and keep the warming trend moderated. Low clouds
and fog could continue to linger into the afternoon hours each
day, keeping the beaches shrouded in cloud cover.

Due to the hot weather forecast early in the month of June, the
climate normals are much lower. An excessive heat watch remains
in effect for Wednesday and Wednesday evening for the interior
portions of the area, such as the interior San Luis Obispo County
valleys, and the Antelope Valley and adjacent foothill areas.
Forecast highs are poised to be close to 15-20 degrees above
normal for this time of year on Wednesday.

.LONG TERM (THU-SUN)...03/521 AM.

A hot weather pattern will continue well away from the coast into
Thursday, and possibly into Friday. The forecast ensembles are
warming temperatures for Thursday and Friday. On Wednesday, NBM
solutions now give a greater chance of 100 and 105 degree high
temperatures for KPMD, KWJF, and KPRB. There is a greater than 95
percent chance of high temperatures reaching 100 degrees out in
the Antelope Valley and a greater than 75 percent chance of KPRB
reaching 100 degrees on Wednesday. On Thursday, a greater than 85
percent chance exists for the Antelope Valley. With the ensembles
trending warmer, the excessive heat watch on Wednesday and
Wednesday evening was extended into Thursday evening.

A southeast flow pattern still develops for late week and could
bring an early start to the monsoon in southern California. While
low confidence exists at this point, the pattern recognition could
come into play for late week or even into the upcoming weekend as
the trough moving to the south will lift back across the area.
Southeast flow aloft will increase and could pipe subtropical
moisture into the region for late week or over the weekend. Forecast
ensemble members have backed off precipitation for Thursday and
Friday, but it remains a non-zero chance given the pattern. There
are a handful of EPS ensemble members giving precipitation for
KPMD and KGXA for Friday through Sunday with NBM solutions giving
a 5 percent chance of rain for Wrightwood-Big Pines on Friday and
through the weekend.

&&

.AVIATION...03/1316Z.

At 12Z at KLAX, the marine layer was 3000 ft deep. The top of the
inversion was at 4300 feet with a temperature of 19 deg C.

Another deep marine layer, but the cloud field was not as solid as
it has been. However, clouds were filling in, and by sunrise,
clouds should be widespread in all coastal and valley areas with
the exception of the portions of southern SBA County, portions of
the valleys of VTU County, and the Cuyama Valley. Clouds were
also pushing into the coastal slopes. Conditions were mostly MVFR
across L.A. County, (except IFR to VLIFR in the foothills), and
IFR to VLIFR from Ventura County northward. Expect skies to clear
by late morning in the valleys, and by early afternoon across the
coastal plain. Clouds may still linger at some beaches today.
Expect a shallower marine layer tonight, with clouds likely
confined to coastal and lower valley areas. Conds will be IFR to
LIFR, except low LIFR in coastal and some lower valley areas of
L.A. and VTU Counties.

KLAX...Moderate confidence in the 12Z TAF. There is a 20% chance
that cigs will scatter out as early as 19Z. There is a 20% chance
that cigs will not return until at least 06Z. There is a 20%
chance of an east wind component of 7-8 kt from 09Z-16Z Tue.

KBUR...Moderate confidence in the 12Z TAF. There is a 20-30%
chance that cigs will scatter out as early as 17Z. There is a 20%
chance that tonight will remain clear.

&&

.MARINE...03/917 AM.

In the outer waters, Small Craft Advisory (SCA) level NW winds
are expected to increase to Gale Force levels this afternoon (90%
chance), then continue thru late tonight. SCA conds are expected
late tonight thru Tue (90% chance). There is a 30-40% chance of
Gale Force wind gusts late Tue afternoon and evening across the
northern zone (PZZ670) and northwest portion of the central zone
(PZZ673), and a 20-30% chance late Wed afternoon and evening for
the northwest portion of PZZ670. Winds are expected to drop below
advisory levels in the southern zone (PZZ676) late Tue afternoon
or eve, across PZZ673 Wed, and across PZZ670 late Wed night. SCA
level winds are not expected Thu/Fri, but there is a 50% chance of
SCA level seas in northern areas Thu.

In the inner waters N of Pt Sal, steep seas were near advisory
levels this morning, and SCA level NW winds are expected (80%
chance) this afternoon/evening. Winds and seas will likely drop
below SCA levels late tonight/Tue morning, but are likely again
(70% chance) Tue afternoon/eve. SCA conds are not expected late
Tue night thru Fri.

In the southern inner waters, SCA level winds are likely (60-70%
chance) in the western third or so of the SBA Channel this
afternoon thru late tonight. Otherwise, SCA conds are not expected
across the inner waters S of Pt. Conception thru Fri. SE winds
will develop late each night and morning thru Wed or Thu, with
isolated winds around 15 knots thru passages and channels, and
between islands.

Steep and choppy seas will likely affect the outer waters thru at
least Wed night, with choppy seas spreading into western portion
of the SBA Channel and the southern inner waters at times.

There is a chance of dense fog in the waters from Point Mugu
northward late tonight thru Thu, mainly during the late night
thru morning hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Watch now in effect from Wednesday morning
      through Thursday evening for zones 344-381>383. (See LAXNPWLOX).
     Wind Advisory remains in effect from 3 PM this afternoon to 3
      AM PDT Tuesday for zones 349-351. (See LAXNPWLOX).
     Wind Advisory in effect from 6 PM this evening to 3 AM PDT
      Tuesday for zones 350-352. (See LAXNPWLOX).
     Wind Advisory remains in effect until 3 AM PDT Tuesday for
      zones 377-378-381. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Tuesday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until noon PDT today for zones
      670-673-676. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Tuesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall/Sirard
AVIATION...DB
MARINE...DB/Lund
SYNOPSIS...Hall

weather.gov/losangeles

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