901
FXUS66 KLOX 071356
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
656 AM PDT Mon Sep 7 2026

.SYNOPSIS...07/328 AM.

A significant southerly swell will cause hazardous surf
conditions at the beaches through at least Tuesday. Isolated
showers will continue at times through Tuesday. Heat will build
across the region through the next several days, with moderate to
major heat impacts for the coasts and valleys Tuesday through
Thursday.

&&

.SHORT TERM (TDY-WED)...07/553 AM.

***UPDATE***

We have added a a slight chance (5-15%) of
thunderstorms to much of LA County (including LA City), the
northern Ventura mountains and the adjacent waters as a
thunderstorm has already developed well offshore and we expect the
environment will only become more conducive by midday for isolated
thunderstorms. Discussion below has been updated accordingly.

***From Previous Discussion***

Early this morning Tropical Storm Marie was was centered 760
miles SSW of Los Angeles, continuing its northwest trek. This
track will maintain its position well away from southern
California, although the associated tropical moisture and
southerly swells will continue to affect the area. The south
swells have created an ongoing, significant hazard at area
beaches, especially the exposed south facing beaches, with strong
and potentially deadly rip currents (see coastal hazards for
details).

Rapidly increasing heat concerns are the main story over land with
moderate to major heat risk and associated heat products becoming
likely for many areas, especially coastal valleys to coast by
Wednesday.

The main player for the rapid changes is a ridge bulging in from
the east with 500 mb heights steadily increasing from mid 580s to
mid to upper 590s by Wednesday. Weak offshore flow from the north
and possibly east by Wednesday will delay and weaken the sea
breeze influence, allowing the significant heat to build towards
the coast. Widespread highs in the 90s (including near some
coasts) to low 100s will in its own right be hot. However the
potential for extreme humidity (for Southern California) from
incredibly high precipitable waters of 1.5-2 inches, well above
normal ocean temperatures, and even recent or upcoming rainfall
will make it MUCH more miserable outside and also keep temperature
the 70s and 80s well into the evening and even overnight for some
areas. This heat may feel comparable or even slightly worse to
recent heat waves, especially near the coast. Spread the word to
prepare for yet another potential heat wave mid week. Fortunately
this one may be relatively short lived (see long term discussion).

The shower activity that was continuing to stream into LA County
from the southwest early this morning will likely continue at
times through at least this afternoon. There is also a 5-15
percent chance of a thunderstorm focused across much of LA County
(including LA City), northern Ventura County Mountains and the
adjacent waters as mid-level lapse rates near an impressive 7 deg
C/km with moderate elevated instability across LA County with an
emphasis on the northeast portion (mountains and desert). The main
threats with these tropical-like thunderstorms is cloud-to-ground
lightning, and brief heavy downpours.

Enhanced southerly flow due to the sandwiching effect of the
building ridge and the remnants passing well to our west will
likely support at least sporadic showers continuing or reforming
into tonight and especially into Tuesday. The activity may
focused across LA or Ventura County and then shift north while
possibly expanding in coverage. While moderate showers will be
possible within this activity, it should mostly be on the move,
greatly limiting flood concerns.

Isolated shower and thunderstorm activity will likely become
confined to the highest mountains by Wednesday as the
strengthening ridge caps and slightly dries out mid-levels of the
atmosphere.

.LONG TERM (THU-SUN)...07/536 AM.

Upper level ridge of high pressure expected to remain strong
over the area on Thursday, then weaken some on Friday. During
this time, pressure gradients will likely be weakly offshore
to the north and weakly onshore to the east, resulting
in a continuation of hot temperatures with associated
heat impacts across much of the region on Thursday, with a slight
cool-down possible by Friday. There is also the potential for
some weak to moderate sundowner wind activity across southern
Santa Barbara county each evening on Thursday and Friday.

The position of the ridge by Thursday may be favorable for some
monsoon moisture or injection of tropical moisture from the south.
So it will likely continue to be quite humid with weak morning
offshore flow potentially delaying the sea breeze. This type of
pattern could support isolated showers or thunderstorms focused
across the interior.

Below normal confidence Friday into next weekend as the ridge may
break down pretty quickly (30 percent chance) or be somewhat
stubborn. Either way it does look somewhat likely that troughing
off the coast may reestablish at times, keeping the door open for
additional tropical moisture to shuttle into southwest California.

&&

.AVIATION...07/1157Z.

At 08Z at KLAX, there was no marine layer with a weak surface
inversion.

Moderate confidence for KSBA and north and low confidence
elsewhere including the desert TAFs. There is a 20-40 percent
chance of SHRA at times through at least 00Z for LA County TAFs,
highest KLAX/KSMO and KBUR to KLGB. There is a 5-10 percent chance
of a thunderstorm between 20Z-00Z.

50 percent chance that VLIFR cigs/vsbys continue for KWJF through
15Z-16Z. There is a 20 percent chance of brief IFR or lower
cigs/vsbys for KSMX through 16Z.

KLAX...Low confidence in TAF. VSBY may lower 3sm in SHRA. Any
east wind component should remain below 5 kts.

KBUR...Low confidence in the 00Z TAF. VSBY may lower to 2SM
during SHRA.

&&

.MARINE...07/646 AM.

For the waters south of the Channel Islands, there is a slight
chance of thunderstorms through this evening. Any thunderstorm
that storms could produce local gusty and erractic Gale Force
winds and seas, brief heavy downpours, and dangerous cloud-to-
surface lightning.

For the Outer Waters, below Small Craft Advisory (SCA) level
winds and seas are expected into Wednesday, except for local
advisory level gusts around Point Conception each afternoon and
evening. Wednesday evening into at least late next week SCA winds
are likely much of the time.

For the Inner Waters north of Point Sal, there is a 30% chance of
SCA level winds Wednesday afternoon/eve and a 60% chance for
Thursday. Increasing potential for SCA winds Friday into the
weekend.

For the Inner Waters south of Point Conception, localized pockets
of borderline SCA winds are likely Tuesday afternoon and evening.
Winds are likely to be a bit stronger and more widespread on
Wednesday with a 60% chance of advisories being issued. Focus
for SCA winds shifts towards the western portion of the Santa
Barbara Channel Thursday into the weekend.

Tropical moisture will continue to stream over the coastal waters
into Tuesday, bringing a slight chance of showers. Besides today
(mentioned above), a thunderstorm cannot be ruled out across the
outer waters on Tuesday.

A large south swell is impacting the area, causing increased
currents and surges in the vulnerable harbors. Breaking waves may
impact south harbor entrances, particularly for Ventura and Los
Angeles Counties (observed at Ventura Harbor).

&&

.BEACHES...07/642 AM.

There is a slight chance of thunderstorms across Ventura and Los
Angeles County beaches through this evening. Any thunderstorm that
storms could produce local gusty and erractic winds and seas,
brief heavy downpours, and dangerous cloud-to- surface lightning.

Significant coastal impacts are expected across Southern
California beaches through at least Tuesday. A large southeast to
south swell from Hurricane Marie has moved into waters this
weekend with swell heights of 5-7 feet and a period around 13
seconds.

High surf conditions are expected on south-facing beaches of
Ventura and Los Angeles counties, peaking at 5-8 feet with local
sets to 12 feet through today. Potentially life threatening rip
currents will continue as well. The highest surf is near Zuma and
Malibu Beach as well as Long Beach. The Santa Barbara South Coast
will be largely protected from this swell, but there are some
small windows of southeasterly and southwesterly energy that could
cause boosts in the waves. HIGH SURF ADVISORIES remain in place
for Los Angeles and Ventura Counties, with BEACH HAZARDS
STATEMENTS (a step below high surf advisories) in effect for Santa
Barbara and San Luis Obispo Counties.

Moderate coastal flooding has occurred and will continue around
high tides for south facing shores. The actual observed tides
have been running about 6 inches above predictions for sometime
now. The south swell will likely boost that enhancement. As a
result, high tides are expected to reach exceed 7 feet during the
evening high tide.

Expect significant beach erosion, flooded sandy beach areas, bike
paths, and parking lots, as well as low-lying roads. Of
particular concern will be the Alamitos Peninsula area in Long
Beach where coastal flooding will potentially cause local damage
to structures near time of high tide later today, Other areas of
concern the next couple of days include Catalina Island, and
Oxnard to Malibu (including Point Mugu). COASTAL FLOOD ADVISORIES
remain in effect for Los Angeles and Ventura Counties where the
best combination of tides and waves will occur, but Santa Barbara
and San Luis Obispo Counties could also see some isolated issues.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory in effect until 11 PM PDT Tuesday for
      zones 87-354-362-366. (See LAXCFWLOX).
     High Surf Advisory in effect until 11 PM PDT Tuesday for
      zones 87-354-362-366. (See LAXCFWLOX).
     Beach Hazards Statement in effect through Tuesday evening for
      zones 340-346-349-350. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 9 AM PDT this morning
      for zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Munroe/Gomberg
AVIATION...Munroe
MARINE...Black/Lund
BEACHES...RS/Gomberg/KL
SYNOPSIS...Munroe/Schoenfeld

weather.gov/losangeles

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