091
FXUS66 KLOX 040022
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
522 PM PDT Mon Jun 3 2024

.SYNOPSIS...03/224 PM.

A warming trend can be expected 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-THU)...03/222 PM.

Low clouds persisted over much of the L.A. County coast and vlys
early this afternoon, and over some of the coast and vlys of VTU
County and the far SE SBA County coast. Patchy low clouds were
also noted along the beaches of the Central Coast. All the low
clouds S of Point Conception will likely clear to or off the coast
this afternoon. In addition, a fair amount of hi clouds will
continue to move into the forecast area from the N.

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.

Flat upper level ridging will prevail over the forecast area
through tonight, with H5 heights around 585-586 dam. Upper level
ridging will build strongly into srn CA on Tue, with H5 heights
rising to 589 dam, then rise further thru Wed to around 590 dam.
The upper level ridging will linger over srn CA Wed night and Thu
with H5 heights continuing around 590 dam.

The high clouds will continue to move over the region tonight
into Tue with partly cloudy skies overall. However, marine layer
low clouds should still affect the Central Coast although will
likely clear out Tue morning as NE flow sets up. S of Point
Conception, marine layer clouds and fog will affect the coast and
into some of the adjacent vlys, but not quite as far inland as the
last few nights. For Tue night and Wednesday, low clouds and fog
will affect the coast S of Point Conception with little inland
penetration to the adjacent vlys. On Wednesday morning, low
clouds should move from the S and affect parts of the Central
Coast as well. Low clouds and fog will move to coastal areas
rather quickly Wed evening, then spread just a little inland Wed
night into Thu morning. Due to an expected shallow and strong
marine inversion below 1000 ft, it looks like patchy dense fog
will be possible with the low clouds. Otherwise, mostly clear
skies overall can be expected across the region thru Thu, except
low clouds may linger at the beaches especially on Wed and Thu.

As a side note, the upper level flow is forecast to turn E-SE for
Wed and Thu, with some mid-level moisture possibly moving into the
area. It would not be out of the question for some afternoon cu
buildups to occur over the mtns, especially the VTU County mtns.
There is even a non-zero chance of a shower or thunderstorm on Thu
for the mtns but is not reflected in the fcst due to the low chance
(10 percent or less).

Breezy to gusty offshore flow will is expected night and morning
hours mainly over SLO/SBA Counties Tue night thru Thu morning.
Otherwise, normal diurnally driven breezy winds are expected
overall Tue thru Thu.

Temps will heat up thru Wed thanks to the building upper level
high pressure system. For Tue, hi temps should be 3-13 deg above
normal for many areas, increasing to 5-15 deg above normal Wed
except 14-17 deg above normal for the Antelope Vly and SLO County
interior vlys, where there is an Excessive Heat Watch in effect.
Altho temps will cool a couple of degrees on Thu, they will remain
well above normal and the Excessive Heat Watch will continue for
the SLO County interior Vlys and Antelope Vly. The hottest temps
will be in these areas with highs expected to be in the 95-108
range overall. Please see the latest Non-Precipitation Weather
Message (LAXNPWLOX) for further details on the expected heat and
for the current Wind Advisories.

.LONG TERM (FRI-MON)...03/223 PM.

The GFS and EC mean ensembles are in fairly good agreement for
the extended period. The western periphery of an upper level high
over AZ/NM will linger on Fri over srn CA, then should weaken some
on Sat before some upper level troffiness moves into the area Sun
and Mon.

There will still be a non-zero chance of an afternoon shower or
thunderstorm in the mtns on Fri, otherwise dry weather will
prevail during the extended period. Marine layer clouds will
affect the coast and some adjacent vlys each night and morning Fri
thru Sun, then the marine inversion should deepen enough for Sun
night and Mon for widespread low clouds to move well inland over
the region and up to the coastal slopes. Otherwise, mostly clear
skies can be expected thru the period.

A cooling trend is expected Fri thru Mon. Temps will still be a
few degrees above normal Fri, then cool to several degrees below
normal by Mon, except still a few degrees above normal for the
interior vlys and deserts.

&&

.AVIATION...04/0021Z.

At 2355Z at KLAX, the marine layer was 2800 ft deep. The top of
the inversion was at 4500 feet with a temperature of 22 deg C.

Considerable high clouds disrupting the low cloud field this
afternoon. Expect a shallower marine layer tonight, with clouds
likely confined to coastal and lower valley areas. An eddy
circulation will likely keep marine layer depth relatively
higher across LA County where cigs will most likely in MVFR
category (with 20% chance of IFR category). Otherwise, looking
for IFR to LIFR cigs at other coastal/valley TAF sites, with
20% chance of VLIFR conditions at KSMX.

KLAX...Moderate confidence in the 00Z TAF. MVFR cigs likely
to impact KLAX much of tonight into Tuesday morning, with
a 20% chance of IFR cigs. There is a 20% chance of an east wind
component of 7-8 kt from 09Z-17Z Tue.

KBUR...Moderate confidence in the 00Z TAF. Most likely that
MVFR cigs will return late tonight and early Tuesday morning,
with a 20% chance of IFR cigs and also a 20% chance that
skies will remain clear.

&&

.MARINE...03/205 PM.

In the outer waters, NW winds are a little slow to increase to
Gale Force levels this afternoon (90% chance), however they are
still expected to develop and continue thru late tonight. Small
Craft Advisory (SCA) level 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 or Thu
morning. 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, 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 remains in effect from Wednesday morning
      through Thursday evening for zones 344-381>383. (See LAXNPWLOX).
     Wind Advisory remains in effect until 3 AM PDT Tuesday for
      zones 349-351-377-378-381. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 645-650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Tuesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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