594
FXUS66 KLOX 302117
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
217 PM PDT Wed Sep 30 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)...30/201 PM.

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

Gradients continue to trend slightly onshore but not enough to
prevent temperatures from being 4-8 degrees above normal. There
will be at least one more morning of marine layer stratus,
possibly two more for the Central Coast before strong high
pressure aloft and weak offshore flow minimize the chances for any
morning stratus.

For the most part the short and long term forecasts have not
changed and likely won`t change much through next week. Models
continue to advertise a long duration heat wave starting Friday,
peaking Saturday, then leveling off at 10-15 degrees above normal
Sunday through all of next week and into the second week of
October. While the gradients will technically be 2-4mb offshore
and we are entering our typical Santa Ana season, this really is
not a Santa Ana event and winds, for the most part, will be
relatively light in most areas. This is just a very hot air mass
with light offshore flow that will significantly delay the arrival
of any cooling effects from our much warmer than normal ocean.
And while temperatures will be very hot, there may not be
many broken temperature records because heat waves in previous
years were accompanied by a stronger offshore flow with stronger
subsidence aloft to generate additional heat at the surface. So
this heat wave will be most notable for it`s length than the daily
temperatures. On the bright side, with that little offshore flow
humidities should remain on the lower side at least through
Saturday.

In summary, an Extreme Heat Watch has been issued for all coast
and valley areas south of Pt Conception starting on Friday. There
will be warming north of Pt Conception but it will take 1-3 more
days to reach heat advisory levels there so expect additional heat
hazards in the coming days for the Central Coast.

.LONG TERM (SUN-WED)...30/215 PM.

The short term discussion covered most of the long term issues.
Models do indicate some increase in PW`s Sunday and Monday from
newly crowned Hurricane Rachel. Most of this storm is tracking
to the west but it will send some moisture and likely ocean
swells north early next week. There`s even a small (5-15) percent
chance of a shower or thunderstorm, mainly in the mountains.

Also, model solutions are showing even higher temperatures around
mid week associated with a stronger offshore push and downsloping
effects. The latest GFS is indicating 950mb temps in the mid 30s
(celcius) so there is at least a 10-20% chance of reaching record
temperatures during this heat wave.

&&

.AVIATION...30/1713Z.

At 1634Z at KLAX, the marine layer was 1800 ft deep. The top of
the inversion was near 4000 ft with a temps of 24 C.

High confidence in VFR TAFs for KPRB, KWJF, and KPMD.

Moderate confidence in remaining TAFs. Timing of change groups
may be off +/- 2 hours. CIG height accuracy +/- 300 ft of fcst.

Lowest confidence in KBUR & KVNY between 01/10-16Z. There is a
40% chance IFR CIGs do not arrive or last less than an hour.

KLAX...Moderate confidence in TAF. Arrival & clearing times of
IFR CIGs 008 (+/- 200 ft) may be off +/- 2 hours. No significant
wind component expected.

KBUR...Fair confidence in TAF. 40% chance IFR CIGs near 007 do
not arrive or last less than an hour between 01/10-16Z.
No wind issues expected.

&&

.MARINE...30/1252 PM.

Quiet conditions expected across the coastal waters through the
weekend except for localized gusts around 21 kts near Point
Conception, Point Dume, and across the San Pedro Channel starting
Friday.

&&

.BEACHES...30/1252 PM.

Beach Hazards Statement in effect thru 5 PM today for the rip
current and tidal overflow potential.

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).
     Beach Hazards Statement in effect until 5 PM PDT this
      afternoon for zones 87-349-350-354-362-366. (See LAXCFWLOX).
PZ...NONE.

&&

$$

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

weather.gov/losangeles

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