583
FXUS66 KLOX 102124
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
224 PM PDT Thu Sep 10 2026

.SYNOPSIS...10/223 PM.

Extreme heat and humidity will continue today with a high risk
for heat illness. Cooling will start Friday and continune into the
weekend with max temps dropping to below normal. The sticky
tropical air will finally exit the region by this weekend. Marine
layer clouds will likely return to many coastal areas.

&&

.SHORT TERM (TDY-SUN)...10/219 PM.

The very hot and muggy weather has been the main story as of late,
but today should be the last day of these truly oppressive
conditions for Southwest Californians. Temperatures have generally
trended down today due mainly to the positive trend in onshore
flow. While the LAX-DAG gradient is near neutral, the positive
trend has allowed for the onshore winds to kick in much earlier
than yesterday, thus providing some relief to coastal areas.
These hot and humid conditions continue to add to this multi-day
high heat-illness risk event, thus the Extreme Heat Warnings in
place will continue through this evening. Overnight temperatures
will still remain relatively warm tonight, but cooler and less
humid air will make its return tomorrow.

The upper level ridge that has trapped the remnant Marie mositure
and brought very hot temps to the region will finally flatten out
starting tomorrow thanks to an upper level trough swinging down
into the PACNW. This will help usher in a significant cooling
trend which will continue each day through the weekend, bringing
the entire region to below normal for mid-September by
Saturday/Sunday. Most of the region will see temps in the 70s at
the coasts and 80s inland. PWATs will drastically decrease as the
tropical mositure moves out of the region, bringing us to around
0.75 inches by Saturday evening down south. The combination of
cooler temps and drier air will lead to significantly more
tolerable weather across the region.

A slight chance of thunderstorms and showers exists this
afternoon over interior mountains of LA and Ventura Counties,
with the Eastern San Gabriels most favored. With any thunderstorm
that forms, the air is juicy enough to produce heavy downpours
along with gusty winds and lightning. The steering flow remains
fairly weak from the west-southwest direction, so storms will
be slow moving to the northeast. Because of this, there is a low
but non-zero risk for localized flash flooding and the Bridge and
Summit burn scars are within that area of risk.

As far as winds go, we`re looking for onshore flow to increase
each day, which will bring some breezy conditions to the region
this weekend.

Expecting the marine layer to reform and many coastal areas can
expect some evening and morning marine layer clouds as early as
tonight, but best chances this weekend (and best chances along the
Central Coast). One caveat is an expected uptick in Sundowner
winds across SW SB County through Saturday night. This will help
warm things up at the coasts, making it tougher for this area to
cool below normal. It may also inhibit any marine layer formation
from Ventura County to southern SB County. These winds will likely
reach advisory levels each night through Saturday and a Wind
Advisory has been issued for tonight.

.LONG TERM (MON-THU)...10/219 PM.

Not much change through Wednesday, with zonal flow continuing at
the upper levels. Temperatures will remain below seasonal
normals. Weak to moderate onshore flow will continue with light
northerly offshore flow each night through morning. There will
likely be some morning low clouds each day with the greatest
coverage across the Central Coast. Skies, otherwise, will be
mostly clear.

By Thursday, deterministic models and ensembles suggest the ridge
will begin to build back west, which would bring warmer
temperatures to the area once again. Onshore flow to the east is
also forecast to trend weaker slightly weaker Thursday morning.
The greatest question is how progressive this westward movement of
the ridge is, so while temperatures are likely to begin to
increase, to what extent and how quickly remains uncertain. What
does appear to be more clear is that any warming trend will likely
not be nearly as warm as the last couple of days.

No significant wind issues are expected, although there will be
the usual gusty southwesterly winds each afternoon across the
mountains and deserts and the typical near advisory level evening
gusts across the SW corner of SBA county.

&&

.AVIATION...10/1733Z.

At 1645Z at KLAX, the marine layer was 1200 ft deep. The top of
the inversion was at 2300 ft with a temperature of 30 C.

High confidence in VFR conditions for all sites except for
KSMX (60% chc of LIFR), KSBP & KLGB (30% chc of LIFR) from
Fri 11/10Z-16Z.

KLAX...High confidence in VFR TAF. There is a 30% chance that
east wind component reaches 8 kts from Fri 11/09Z-17Z.

KBUR...High confidence in VFR TAF. No wind issues expected.

&&

.MARINE...10/1253 PM.

Conditions are expected to become increasingly hazardous
across the outer waters into the weekend. A Gale Watch
(50-60% chc) has been issued for PZZ676/673 Saturday evening
into Monday morning. The coastal Jet may develop across PZZ670
Saturday evening but confidence is too low if winds will reach
Gale strength at this time. Small Craft Advisory (SCA) conditions
are expected to reach into the nearshore waters along the Central
Coast and the Santa Barbara Channel at times (especially during
afternoon/eve hours).

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning in effect until 8 PM PDT this evening
      for zones 38-87-88-340>358-362-366>375-548. (See LAXNPWLOX).
     Beach Hazards Statement in effect until midnight PDT tonight
      for zones 87-349-350-354-362-366. (See LAXCFWLOX).
     Wind Advisory in effect until 6 AM PDT Friday for zones
      349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 11 PM PDT this evening
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Friday for zone
      650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Monday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 6 PM PDT Saturday for
      zones 673-676. (See LAXMWWLOX).
     Gale Watch in effect from Saturday evening through Monday
      morning for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Lewis
AVIATION...Black
MARINE...Black
SYNOPSIS...Lewis

weather.gov/losangeles

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