969
FXUS66 KLOX 121844
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1144 AM PDT Tue Aug 12 2025

UPDATED AVIATION SECTION

.SYNOPSIS...12/714 AM.

The hot weather across the valleys and interior will continue
into this evening. Night through morning low clouds and fog will
continue along the coast and into some coastal valleys through the
period and will prevent those areas form heating up. A cooling
trend will begin Wednesday as an upper-level trough influences
the West Coast.

&&

.SHORT TERM (TDY-THU)...12/811 AM.

***UPDATE***

GOES fire products showing the Gifford Fire burning in central San
Luis Obispo County, with smoke visibly streaming to the SSE into
Santa Barbara County. Marine clouds are all along the central
coast as well as southern Ventura and LA Counties. Temperatures
are similar to this time yesterday, and already into the upper 80s
in portions of the Antelope Valley. Not anticipating any
extension of the heat products, which are in effect until this
evening. No impactful changes from the previous discussion.

***From Previous Discussion***

The marine layer is about 1000 ft deep which is deep enough to
get into the Santa Ynez Vly and portions of the San Gabriel Vly.
Currently there are no clouds from Santa Monica northward but the
low clouds should fill in by dawn, except there is a 30 percent
chc that the SBA south coast will remain clear.

Max temps are the main talking point for today`s forecast. An
upper high sitting atop of the state is keeping a heat dome over
the area. Strong onshore flow to the east in the afternoon is
creating downsloping warming winds across the Antelope Vly. This
will bring very dangerous heat to these areas and an extreme heat
warning is in effect for these areas where max temps will range
from 105 to 108 degrees. Most of the rest of the interior sections
including the lower mtn elevations are under a heat advisory for
max temps from 100 to 104 degrees. Please see the product
LAXNPWLOX for all of the heat related details.

There will be another Sundowner tonight across the western portion
of the SBA south coast but this on looks a tad weaker than last
evenings and should come in just under advisory levels.

The ridge begins to break down on Wednesday with hgts falling to
592 dam. On Thursday the ridge is pushed to the east by trof and
hgts fall further to 588 dam. At the same time the eddy is
forecast to spin up and this will increase amount of night
through morning low clouds and fog. Max temps will cool 2 to 4
locally 6 degrees on Wed with most areas seeing an addition 2 to 4
degrees of cooling (4 to 6 degrees across the LA mtns and
Antelope Vly) on Thursday. While there will be plenty of 100 to
102 degree heat in the interior (103 to 104 degrees in the
Antelope Vly) the 2 to 4 degrees of cooling should be just enough
to prevent heat advisories. By Thursday most of the csts/vlys will
see max temps in the 70s/80s a with only 90s across the interior.

There will be a stronger Sundowner Wednesday evening and a wind
advisory is likely for the western portion of the SBA south coast.

.LONG TERM (FRI-MON)...12/1221 AM.

A fairly static pattern will dominate the long term. Long wave
troffing will be over the state on Fri/Sat. On Sunday the trof
will move to the west and set up over east PAC. Hgts will be near
588 dam through the period. Somewhat atypical (for August)
onshore flow will continue through the period. Look for strong
onshore flow to the north and east in the afternoon becoming weak
to mdt due to the diurnal pressure curve in the early morning.

A persistent night through morning low cloud pattern will
continue along the coasts. There will only be limited valley
penetration (The Santa Ynez Vly will be the notable exception)as
the hgts will likely keep the marine layer under 1000 ft.

There will be two days of cooling Fri/Sat with Saturday`s max
temps ranging from near 70 across the near shore area with 70s
across the rest of the coastal areas. The vlys will end up only in
the 80s. These max temps are mostly 5 to 10 degrees below normal.

The strong onshore push to the east will generate gusty afternoon
winds across the some mtns and the western Antelope Vly. These
winds will create locally elevated fire wx conditions.

&&

.AVIATION...12/1843Z.

At 1626Z at KLAX, the marine layer was 2000 ft deep. The top of
the inversion was at 4200 ft with a temperature of 26 C.

High confidence in VFR TAFs at KPMD, and KWJF.

Moderate confidence in TAFs for KPRB, KBUR, and KVNY. There is a
20-30% chance for LIFR to IFR cigs at each sites after 08Z, with
highest chances at KBUR and KVNY.

Moderate confidence in coastal TAFs. Timing of arrival of cigs
for KSBP, KSMX, KSMO, KLAX, and KSMO may be off +/- 2 hours. For
KOXR, and KCMA, timing may be off +/- 3 hours, and there is a
chance for now low clouds at KOXR (20%) and KCMA (40%). Minimum
flight cat may be off by one cat.

Vis reduction due to FU from Gifford Fire is possible at times
for KSBP, KSMX, KSBA, & KPRB.

KLAX...Moderate confidence in TAF. Return of cigs could occur as
early as 01Z. Minimum cig height could be off +/- 200 ft. Moderate
confidence in any east wind component remaining below 6 kts.

KBUR...Moderate confidence in TAF. There is 30% chance of cigs
004-010 after 08Z, but low confidence on cig heights. Vsbys may be
as low as 1SM if cigs arrive.

&&

.MARINE...12/755 AM.

High confidence in seasonal NW winds across the Outer Waters and
Inner Waters along the Central Coast, with 40-70% chance of
reaching Small Craft Advisory (SCA) in the afternoon through late
night hours each day through the week. Highest confidence in the
southern Outer Waters, especially Wednesday and beyond. There is a
30% chance of local GALE Force wind gusts around Point Conception
to San Nicolas Island Wednesday afternoon and evening, as well as
Thursday afternoon through at least Friday morning for all the
outer waters. Seas may approach 10 feet across western portions
of PZZ670 on Friday.

For the Inner Waters south of Point Conception, moderate
confidence in SCA level wind gusts in the western portion of the
Santa Barbara Channel in the afternoon and evenings through
the week, then there is a 50-60% chance for winds to increase to
SCA levels in the eastern portion of the zone Wednesday and
Thursday afternoon and evening. Otherwise and elsewhere,
conditions will remain below SCA levels through the week.

In addition, night to morning dense fog may continue at times
into Wednesday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect until 9 PM PDT this evening
      for zones 38-351>353-376>380. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Wednesday evening
      for zones 354-362-366. (See LAXCFWLOX).
     Extreme Heat Warning in effect until 9 PM PDT this evening
      for zones 381>383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke/jld
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...jld

weather.gov/losangeles

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