067
FXUS66 KLOX 180634
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1134 PM PDT Mon Aug 17 2026

.SYNOPSIS...17/848 PM.

Night through morning marine layer clouds will be confined to the
coastal areas through much of this week. Warmer and drier
conditions are expected away from the immediate coast, with peak
heat likely being Tuesday through Thursday when moderate heat risk
is expected in warmest locations.

&&

.SHORT TERM (MON-THU)...17/846 PM.

***UPDATE***

Little overall change to the forecast with building high pressure,
lingering marine layer clouds and warming temperatures. Expecting
marine layer clouds to return to the Central Coast, with far less
cloud coverage south of Point Conception. Highs today ranged from
the 80s to low 100s most places, with the exception of the coasts,
which saw highs in the 60s to low 70s up north, and upper 70s to
low 80s south. Gusty north sundowner winds have developed tonight
along western portions of the Santa Barbara south coast, with
gusts from 20 to 35 mph. These winds will strengthen over the next
few hours, and a short duration wind advisory may be needed. There
is potential for a return of monsoonal moisture by Friday, and
(5-10%) chances were expanded to the eastern San Gabriel mountains
and eastern Antelope Valley. Otherwise, the forecast looks on
track.

***From Previous Discussion***

Heat continues to be the main story this week as a very large
upper high shifts westward from Texas to Arizona over the next few
days. 500 mb heights will increase from around 592 dam to 594/595
dam on Tuesday. Meanwhile, the surface gradients won`t change too
much, with the general trends of the W/E (LAX-DAG) gradient
weakly onshore during the mornings, increasing slightly during
the afternoons, while the N/S (LAX-BFL) gradient near neutral or
weakly offshore in the mornings becoming weakly onshore in the
afternoons.

Between the slight increase in 500 mb heights and the weak onshore
flow in the morning, marine layer clouds will stay confined to the
coastal locations south of Point Conception (if they even get to
the beaches at all). For the Central Coast, good confidence in
marine layer clouds each morning.

The high pressure with higher than normal heights for this time of
year, along with weaker than normal onshore flow, will bring
another round of heat to Southern CA. Temperatures will increase
each day through at least Thursday, bringing above normal temps
to all areas, save for the Central Coast which will end up a few
degrees within to below normal. 2 to 4 degrees of warming (locally
6 degrees across the Central Coast) will occur Tuesday and an
additional 1 or 2 degrees of warming on Wednesday. Thursday, 1 to
2 degrees of warming will be possible for Ventura and Los Angeles
Counties, though up to 3 degrees of cooling is possible for the
Central Coast. The strong inversion, much warmer than normal sea
surface temps and the warm atmosphere will also bring warmer than
normal overnight low temps to much of the area. Most coast/valley
locations will only have lows in the upper 60s to lower 70s.

The combination of warmer than normal highs and lows will bring
Moderate HeatRisk to many areas. Heat advisories go into effect
Tuesday through Thursday for the San Fernando, San Gabriel, and
Santa Clarita Valleys as well as the lower mtn elevations. There
is a 40 percent chance the downtown monsoonal moisture by Friday,
and (5-10%) chances were expanded tA area, the VTA county
valleys, and the Santa Monica mountains will also need heat
advisories starting Wednesday. Additionally, there is a small
chance that heat advisories will need to be extended into Friday.
Please see the product LAXNPWLOX for all of the details.

Gusty north winds will affect southwest Santa Barbara County and
the I-5 corridor near the Grapevine each evening and overnight.
While most of these winds are expected to remain below advisory
levels, there is a chance for advisory level winds in the Gaviota
area this evening.

.LONG TERM (FRI-MON)...17/136 PM.

There will be a little bit of cooling on Friday mostly due to an
increase in mid and high level clouds. Still, max temps will
remain well above normal, and like mentioned in the short term
discussion, there is a small chance of heat advisories needing to
be extended for portions of the area.

The upper high is forecast to migrate to the four corners area by
Thursday night, which will set up SE monsoon flow over Southern
CA. This SE flow will allow precipitable Water values to approach
1.5" across southern L.A. County starting Friday afternoon. This
influx of moisture will allow for a 5-10 percent chance of showers
or thunderstorms to to develop over the LA County mountains and
Antelope Valley Friday afternoon through the weekend.

The upper high will be nudged a little to the east over the
weekend as a weak trof moves through the PACNW and the northern
half of CA. The weak lift from the trof may bring a little better
low cloud development, although this is far from certain. Look
for 1 to 2 degrees of cooling each day - maybe a little more for
SLO county due to the proximity to the trof. The cooling will
bring most areas north of Pt Conception down to near or below
normal temps. South of Pt Conception, however, most max temps will
remain a few degrees above normal.

&&

.AVIATION...18/0607Z.

At 0534Z at KLAX, the marine layer was 600 feet deep. The top of
the inversion was 2300 feet with a temperature of 28 C.

High confidence in TAFs for KBUR, KVNY, KPMD and KWJF.

Fair confidence in TAFs for KSBP and KSMX. VFR conds could arrive
+/- 1 hour from fcst time. There is a 25 percent chc of 1/4-1/2SM
vsbys 11Z-15Z.

Moderate confidence in the remainder of TAFs with a 30 percent
chc of IFR cigs at any given site 10Z-17Z.

KLAX...Moderate confidence in TAF. There is a 30 percent chance
of BKN008 conds 10Z-17Z. No significant easterly wind component
is expected.

KBUR...High confidence in CAVOK TAF.

&&

.MARINE...17/906 PM.

For the Outer Waters, high confidence in current forecast. Small
Craft Advisory (SCA) level winds are expected through Saturday.
Building short- period seas will also affect the Outer Waters,
rising to the 6-9 foot range.

For the Inner Waters north of Point Sal, moderate confidence in
current forecast. Through Wednesday, there is a 30-40% chance of
SCA level winds in the afternoon and evening hours. For Thursday
through Saturday, there is a 50-70% chance of SCA level winds in
the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For the western half of the Santa
Barbara Channel, there is a 60% chance of SCA level winds late
this afternoon and tonight. Then there is a 30-40% chance of SCA
level winds during the afternoon to evening hours Wednesday
through Saturday. Elsewhere south of Point Conception, high
confidence in winds and seas remaining below SCA levels through
Saturday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory in effect from 10 AM Tuesday to 8 PM PDT
      Thursday for zones
      38-88-343>345-351-353-371>373-375-376-379-380-548. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Phillips/Lund
AVIATION...Rorke
MARINE...RAT/Ciliberti
SYNOPSIS...Gomberg/Ciliberti

weather.gov/losangeles

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