457
FXUS66 KLOX 170950
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
250 AM PDT Mon Aug 17 2026

.SYNOPSIS...17/245 AM.

Night through morning marine layer clouds will be confined to the
near 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 (TDY-WED)...17/245 AM.

Over the next three days a very large and hot upper high,
currently centered over TX, will shift to the west and end up over
AZ. Hgts will no change much and will sit near 594 dam through the
period. The sfc gradients will not exhibit much change either. The
N/S gradient will be near neutral in the morning and weakly
onshore in the afternoon. The W/E gradient will be weakly onshore
in the morning and moderately onshore in the afternoons.

Marine layer clouds will be confined to the coastal sections. Good
confidence that the Central Coast will have the low clouds each
morning. Less confidence for the csts south of Pt Conception where
beaches could be clear on any given morning.

The high pressure, hier than normal hgts and weaker than normal
onshore flow will bring another round of heat to Srn CA. Most
areas will see 2 to 4 degrees of warming today although some vly
areas will see up to 6 degrees. This warming will bring warmer
than normal temps to all areas save for the Central Coast which
will end up 2 or 3 degrees blo normal. Another 2 to 4 degrees of
warming (locally 6 degrees across the Central Coast) Tuesday will
bring above normal max temps to all areas. Most areas will see 1
or 2 degrees of additional warming on Wednesday. The strong
inversion, much warmer than normal sea sfc temps and the warm
atmosphere will also bring warmer than normal overnight low temps
to much of the area. Most cst/vly locations will only have lows in
the upper 60s to lower 70s.

The combination of warmer than normal highs and lows will bring
significant heat risk to many areas. HEat advisories were issued
Sunday 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 LA area, the VTA county vlys, and the
Santa Monica mtns will also need heat advisories starting
Wednesday. 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
to San Marcos Pass area.

.LONG TERM (THU-SUN)...17/245 AM.

Thursday will greatly resemble Wednesday as there will be little
change in any of the synoptic parameters. The only change will be
some cooling across the Central Coast as that area will have a
stronger sea breeze.

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. The upper high is forecast to migrate to the
four corners area which will set up SE monsoon flow over Srn CA.
PWs approach 1.5" across Srn LA county. This influx of moisture
will allow for a non zero chc of showers or TSTMs to develop over
the mtns and Antelope Vly.

The upper high will be nudged to the east for the weekend as a
weak trof moves through the PACNW and the northern half of the
state. 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...17/0945Z.

At 0832Z at KLAX, the marine layer was at 900 feet deep. The top
of the inversion was near 1800 feet with a temperature of 26 C.

High confidence in VFR TAFs for KBUR, KVNY, KPMD & KWJF.

Low to moderate confidence in remaining TAFs. VFR timing may be
off +/- 90 minutes. Cig hgt may be off by +/- 200 ft. There is a
20 percent chc of no cigs at any site south of Pt Conception.

KLAX...Moderate confidence in TAF. There is a 30 percent chc of
OVC008 conds. No significant east wind component expected.

KBUR...High confidence in VFR TAF.

&&

.MARINE...17/250 AM.

Moderate to high confidence in forecast. Current Small Craft
Advisory (SCA) for gusty winds over the outer waters from near
Point Conception southward to San Nicolas Island and in the
vicinity of the Channel Islands is on track. Good chance for SCA
winds to be ongoing from through much of the week over all of the
outer waters starting this evening. Nearshore along the Central
Coast, afternoon through evening SCA winds are likely Tuesday
through Friday.

For the inner waters, SCA winds will affect the western SBA
Channel this afternoon and tonight. This pattern will continue,
with SCA winds in the afternoon and overnight period, decreasing
into the morning hours each day. For PZZ655, SCA winds are not
expected, although local gusts to 25 knots are likely nearshore in
the afternoon and evening hours through Wednesday.

Building short period seas are expected over the next several
days, likely rising to around 7-9 feet over the outer waters.

&&

.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 Tuesday for
      zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...Ciliberti
SYNOPSIS...Gomberg/Ciliberti

weather.gov/losangeles

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