484
FXUS66 KLOX 110555
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1055 PM PDT Thu Sep 10 2026

.SYNOPSIS...10/601 PM.

A cooling trend will affect the region Friday into the weekend
with max temps dropping to below normal by Sunday. The sticky
tropical air will finally exit the region by this weekend. Marine
layer clouds will likely return to many coastal areas.

&&

.SHORT TERM (THU-SUN)...10/923 PM.

***UPDATE***

It was a mostly sunny day today, with some altocumulus cloud build
ups over the mountains, and a few thunderstorms over the Eastern
San Gabriel Mountains this afternoon. High temperatures across
most coasts and coastal valleys were 5 to 10 degrees cooler than
yesterday, while more interior areas were a couple degrees warmer.
These temperatures ranged from 80s and 90s at the coasts to 90s
to low 100s everywhere else, about 10 to 20 degrees above normal
for this time of year.

Overnight lows will remain elevated in the 60s to mid 70s. The
forecast leans toward a return of marine layer clouds tonight
across the Central Coast, and possibly into the southern L.A.
Coasts around Long Beach, but less confidence than normal as the
first night of marine layer clouds is always tricky to forecast
and models rarely handle it well. Additionally, advisory level
Sundowner winds across Southwestern Santa Barbara County are
expected to continue through the night and a Wind Advisory is in
effect.

As for tomorrow, onshore flow is expected to increase further,
while 500 mb heights will decrease by about 3 dam, and PWATs
will start to decrease through the day. The combination of the
three will allow widespread cooling across the region, with some
locations decreasing by as much as 8 degrees. Temperatures are
forecast to be in the 70s and 80s at the coast and 80s and high
90s away from the coast.

Allowed the Extreme Heat Warnings to expire on time at 8pm PDT.
However, just issued Heat Advisories for the coasts south of Point
Conception, including the inland coasts of Ventura and L.A.
Counties due to the continued very warm overnight lows and
expected highs of around 10 degrees above normal.

Otherwise forecast was in shape and no other updates were needed
for this evening.

***From Previous Discussion***

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...11/0554Z.

At 0509Z at KLAX, there was no marine layer. The top of the
inversion was at 2800 ft with a temperature of 30 C.

High confidence in VFR conditions for all inland sites.

Low confidence in TAFs for KSMX and KSBP where there is a 30-40
percent chc of LIFR conds 11Z-16Z. Moderate confidence in TAFS for
KLAX, KSMO and KLGB where there is 30 percent chc of IFR cigs
12Z-16Z. Fair confidence in TAFs for KSBA, KOXR and KCMA with a 15
percent chc of IFR cigs 12Z-16Z.

KLAX...Moderate confidence in TAF. There is a 30% chance of BKN008
conds 12Z-16Z. There is a 30% chance that east wind component
reaches 8 kts 06Z-16Z.

KBUR...High confidence in TAF.

&&

.MARINE...10/738 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 causing winds to increase there as well, but
confidence in winds reaching Gale force is low at this time.
Otherwise, SCA winds are expected across the outer waters through
Saturday afternoon or longer. 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) through early next week.

&&

.BEACHES...10/823 PM.

The potential for moderate coastal flooding will continue through
this evening, mainly around evening high tide for south facing
shores. Even though the south swell from post tropical cyclone
Marie is subsiding, the tides remain very high. The actual
observed tides have been running about 6 to 8 inches above
predictions, with the evening tides near or exceeding 7 feet.

While impacts will not be as extreme as the past few days,
possible impacts include continued beach erosion, flooded sandy
beach areas, bike paths, and parking lots, as well as low-lying
roads. Some areas that may continue to see impacts are: the
Alamitos Peninsula in Long Beach, Avalon on Catalina Island, and
Oxnard to Malibu (including the Pacific Coast Highway near Point
Mugu).

Beach Hazards Statements (BHS, CFWLOX) are in effect through this
evening for the beaches of Los Angeles, Ventura, and southern
Santa Barbara Counties due to these very high evening tides.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect until midnight PDT tonight
      for zones 87-349-350-354-362-366. (See LAXCFWLOX).
     Heat Advisory in effect until 6 PM PDT Friday for zones
      349-350-354-355-362-366>368. (See LAXNPWLOX).
     Wind Advisory in effect until 6 AM PDT Friday for zones
      349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 PM to 9 PM PDT Friday
      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 from 3 PM Friday to 3 AM PDT
      Saturday 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/KL
AVIATION...Rorke
MARINE...Black/Ciliberti
BEACHES...Ciliberti
SYNOPSIS...Lewis/Ciliberti

weather.gov/losangeles

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