034
FXUS66 KLOX 012204
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
304 PM PDT Mon Sep 1 2025

.SYNOPSIS...01/213 PM.

Very warm weather is expected today and tomorrow. Monsoonal
moisture will arrive tonight and last through at least Thursday.
There is a chance of thunderstorms and showers focused over the
Antelope Valley and San Gabriel Mountains late Tuesday morning
through Wednesday evening. Any storms may produce lightning,
flash flooding, and gusty and locally damaging winds.

&&

.SHORT TERM (TDY-THU)...01/304 PM.

Another very warm to hot day is expected today, although the
impact of stronger onshore flow and upper level clouds late in the
day may dampen daytime maximum temperatures. Heat Advisories are
in effect for much of the areas through Tuesday, with a small
chance of some headlines being extended into Wednesday and/or
expanded to include the coasts of LA/Ventura Counties.

Mositure and instability from the convective activity currently
over Baja California will intersect the region late tonight into
Tuesday. Chances of thunderstorms will begin tonight with a 10-20
percent chance of storms for most areas south of Point Conception
(including the coastal waters, coasts and valleys). Tonight
through tomorrow morning the the main threat with storms will be
lighting fire starts and gusty and erratic outflow winds (gusts
35-50 mph), as moisture will be elevated. Starting tomorrow
afternoon, widespread showers will become increasingly likely,
with thunderstorm chances focused over the mountains of LA and
Ventura Counties and the Antelope Valley. A Flood Watch has been
issued from 11 AM Tue to 11 PM Wed, for much of the San Gabriel
Mountains and the Antelope Valley (including the Bridge Fire Burn
Scar), due to a long duration of risk of flash flooding from
thunderstorms with a risk for damaging winds gusts up to 60 mph.
There is a chance for high clouds to inhibit thunderstorm
development somewhat Tuesday afternoon, however vorticity will
maintain chances for showers/thunderstorms during the less typical
overnight and Wednesday morning hours, thus the reasoning for
long duration Flood Watch. Moderate steering flow out of the west
will provide some storm motion on Tuesday, but by Wednesday
steering flow expected to weaken with slower moving storms
favored.

Overall confidence in high temperatures will be low through the
week due to many variables at play, including elevated 500 mb
heights, light offshore flow at times, increasing cloud coverage,
and higher humidity. Thunderstorm chances are likely to continue
through Thursday, and marine layer clouds will likely be minimal
for most coasts and valleys.

.LONG TERM (FRI-MON)...01/208 PM.

A pattern shift is likely starting Friday, as a weak trough digs
into the region, cooling temperatures and bringing dry
southwesterly flow aloft. This will lead to a drop off in
monsoonal mositure, although a chance for thunderstorms may
linger into Friday. Saturday into early next week, lower 500 mb
heights combined with stronger onshore flow will result in
temperatures near or below normal across the area.

&&

.AVIATION...01/1804Z.

At 17Z at KLAX, the marine layer was 700 ft deep. The top of the
inversion was at 3400 ft with a temperature of 27 C.

Moderate confidence in the 18Z TAFs at the coastal airfields.
Most coastal airfields should have low clouds and IFR/LIFR conds
tonight into Tue morning, but confidence in timing may be off +/-
an hour or two. There is also a 30% chance of no low clouds for
KLAX and KLGB due to mid and hi clouds moving in tonight possibly
disrupting the low cloud development.

Hi confidence for the 18Z TAFs over the vlys and deserts.

There is also a slight chance of showers and thunderstorms for
many areas S of Point Conception late tonight into Tue.

KLAX...Moderate confidence in the 18Z TAF. The airfield should
have low clouds and IFR conds tonight into Tue morning, but
confidence in timing may be off +/- an hour or two. There is also
a 30% chance of no low clouds due to mid and hi clouds moving in
tonight possibly disrupting the low cloud development. High
confidence that any east wind component will remain below 7 kt.

KBUR...High confidence in the 18Z TAF.

&&

.MARINE...01/127 PM.

There is a slight chance of thunderstorms over the Inner Waters
south of Point Conception late tonight through Tuesday morning,
especially the waters adjacent to the Los Angeles and Orange
County coasts. Any thunderstorm may produce frequent lightning,
rain, and gusty, erratic winds.

There is a 30% chance of winds increasing to SCA levels over the
outer waters this afternoon and evening. For Tuesday through
Thursday night, winds will increase across the central and
southern outer waters, with the highest chances for SCA winds
focused around Point Conception south to San Nicolas Island. A
relative lull in winds will be likely each morning. Conds should
then be just below SCA levels Friday through Saturday night.

Moderate confidence in forecast for the nearshore waters along
the Central Coast. Winds and seas will remain below SCA levels
through Saturday night, but winds look to increase Tuesday and
Friday afternoon and evening with a 20-30% chance of SCA conds.

Aside from seasonal afternoon thru evening localized NW wind
gusts to 20 kts in the far Western Portion of the Santa Barbara
Channel and the San Pedro Channel, light winds and small seas will
be common for the nearshore waters south of Point Conception
through tonight. Winds will increase in speed and coverage
Tuesday through Thursday, with a chance of SCA conds Tuesday and
Wednesday during the afternoon and evening across western
portions of the waters, as well as near Point Dume and into the
San Pedro Channel. Conds should then remain below SCA levels
Friday through Saturday night.

&&

.BEACHES...01/110 PM.

A long period southerly swell will continue through this evening.
Hazardous rip currents are likely for Los Angeles and Ventura
County beaches, as well as Central Coast beaches. Elevated surf
(up to 6 feet) will be possible at south and southwest facing
beaches during the period. If you are at the beach this Labor Day
Weekend, swim near a lifeguard tower and stay aware of ocean
conditions.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect until 6 PM PDT Tuesday for
      zones 38-88-344-345-352-353-355>358-368>379-548. (See LAXNPWLOX).
     Beach Hazards Statement in effect until 11 PM PDT this
      evening for zones 340-346-354-362-366. (See LAXCFWLOX).
     Flood Watch in effect from Tuesday morning through Wednesday
      evening for zones 379>383. (See LAXFFALOX).
PZ...NONE.

&&

$$

PUBLIC...Schoenfeld
AVIATION...Sirard
MARINE...Sirard
BEACHES...Sirard
SYNOPSIS...Schoenfeld

weather.gov/losangeles

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