695
FXUS66 KLOX 010949
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
249 AM PDT Thu Oct 1 2026

.SYNOPSIS...30/113 PM.

Little change in weather conditions is expected through Thursday
with temperatures 4-8 degrees above normal. Areas of morning low
clouds and fog are possible near the coast as well. A major and
long lasting heat wave will begin Friday and last through all of
next week at least with with dangerously hot temperatures.

&&

.SHORT TERM (TDY-SAT)...01/249 AM.

***A VERY DANGEROUS AND LONG LASTING HEAT WAVE FRIDAY THROUGH AT
 LEAST NEXT WEEK AND LIKELY EXTENDING INTO THE SECOND WEEK IN
 OCTOBER***

Today will hint at the upcoming heat wave. An upper high will
slide over Srn CA and raise hgts to ~589 dam. There will be near
neutral sfc flow in the morning and weak onshore flow in the
afternoon. An eddy has brought low clouds to most of the csts and
some of the lower vlys. The marine layer is shallow enough across
SLO and SBA counties to allow for some dense fog to form. The
marine layer and weak onshore flow will keep coastal temps similar
to ydy. The hgts rises and subsidence from the building upper
high will bring 3 to 5 degrees of warming to the vlys mtns and far
interior. Most temps across the csts/vlys will be 3 to 6 degrees
above normal. Look for 10 degrees above normal temps further
inland.

The well advertised long duration heat wave kicks off on Friday.
Weak offshore flow will develop in the morning, but it will not be
strong enough to prevent some marine layer low clouds from
forming. The upper high will stretch over Srn CA and Srn NV with
590 dam. The weak offshore flow and high pressure aloft will team
up to produce 4 to 8 degrees of warming across the csts and vlys.
Most coastal areas will see highs in the mid and upper 80s except
the LA cst will likely see plenty of high in the lower to mid 90.
The vly temps will soar into the upper 90s to 105 degrees. These
max temps 10 to 15 degrees over normal will pose heat health
hazards to the area. An extreme heat watch goes into effect for
all of the csts and vlys south of Pt Conception and will continue
through the short and long term periods.

Saturday will feature even stronger offshore flow in the morning
(but still weak enough to not produce much if any canyon winds) and
even weaker onshore flow in the afternoon. This will make
Saturday the hottest of the next 7. There will be an additional 2
to 4 locally 6 degrees of warming across the csts and vlys. This
warming will push most cstl temps into the 90s and and vly temps
to 100 to 107. Max temps will end up 15 to 20 degrees over
normals.

The offshore flow will mean that this heat will feature much less
humidity than the previous heat events in August and September.

The Central Coast will have warmer than normal temps but will
remain just under heat headline criteria. Still residents there
should take heat precautions when exercising or working outdoors.

.LONG TERM (SUN-WED)...01/249 AM.

The xtnd forecast shows little change in the heat. There may be a
couple degrees of cooling from Saturday`s very hot numbers but no
where near enough to reduce the heat danger. The combination of
light offshore flow and high pressure aloft will allow for little
day to day change in max temps Mon Tue and Wed. Max temps during
this period will mostly be 10 to 15 degrees above normal. Weak
offshore flow overnight and a strong inversion likely around 900
ft will keep overnight lows above normal as well limiting the
body`s ability to recover overnight.

Another heat related problem will be an increase in humidity
courtesy of Hurricane Rachel. The increased in humidities will
arrive Monday and will likely continue through Wednesday. Rachel
is forecast to track to the west it will send ocean swells along
with the aforementioned moisture . There`s even a small (5-15)
percent chance of a mtn shower or thunderstorm in the afternoons.

Even through this heat wave will not likely produce record heat it
will still be very dangerous due to the prolonged duration of the
event. The relentless heat will have a hazardous wearing down
effect on people esp the very young and old.

One bit of good news the long range mdls are now showing cooler
temps arriving a few days earlier than with the fcst ydy. Today`s
mdls show improving conditions starting around the 10th rather
than the 13th.

&&

.AVIATION...01/0948Z.

At 0505Z at KLAX, the marine layer was 1100 ft deep. The top of
the inversion was near 3000 ft with a maximum temp of 25 C.

High confidence in VFR TAFs for KWJF and KPMD.

Low confidence in KBUR & KVNY TAFs with a 40 percent chc of no low
clouds (or only for a very brief time)

Moderate confidence in remaining TAFs. Timing of change groups
may be off +/- 2 hours. CIG height accuracy +/- 300 ft of fcst.
There is a 30 percent chc that KSBA will not see vis AOB 3/4SM.

KLAX...Moderate confidence in TAF. VFR conds may arrive as late as
2000Z. There is a 30 percent chc of OVC012 conds aft 15Z. No
significant east wind component expected.

KBUR...Low confidence in TAF. There is a 40% chance of no low
clouds or only a brief 30 to 40 minute period of low clouds.

&&

.MARINE...01/244 AM.

Lingering swell near 10 feet for the far northern outer waters is
expected to trend downwards going forward. Local areas of Small
Craft Advisory Level (SCA) gusts are possible each afternoon and
evening through at least Saturday, for areas around Point
Conception, off the coast of Point Dume, and across the San Pedro
Channel. Beside the aforementioned areas, quiet marine conditions
are expected for the rest of the coastal waters.

&&

.BEACHES...30/801 PM.

Beach Hazards Statement has been allowed to expire.

While we will get a break from the coastal flooding concerns for
the rest of the week, another hurricane swell (from Rachel) will
likely bring a larger-than-Polo south swell to southern California
for the early to middle part of next week. Thankfully tides at
that time will not be extreme, but they should be around 6.5 feet
which is high enough to cause some concern, but it all depends on
how big the surf ends up. Stay tuned for future updates.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Watch in effect from Friday morning through
      Thursday evening for zones
      38-87-88-349>358-362-366>375-548-550. (See LAXNPWLOX).
PZ...NONE.

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...Black/RS
BEACHES...RK/DB
SYNOPSIS...MW

weather.gov/losangeles

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