232
FXUS66 KLOX 240551
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1051 PM PDT Sun Aug 23 2026

.SYNOPSIS...23/1045 PM.

Very hot conditions will dominate the week, with a high risk for
heat illness. Patchy night through morning low clouds and locally
dense fog will be confined to coastal areas, mainly north of
Point Conception.

&&

.SHORT TERM (TDY-TUE)...23/818 PM.

A large dome of high pressure aloft, affecting the southern half
of the United States, will dominate the week ahead. The core of
the high is currently centered over New Mexico and Texas, and will
change little through Monday, but then start to shift to the west
on Tuesday. By Thursday, the core of the high will be centered
over Arizona, right on our doorstep. Meanwhile, Onshore flow will
weaken a little and the low-level prevailing flow will become more
northerly. These two ingredients will bring even hotter
conditions that what we saw over the weekend, with the noticeable
jump happening on Tuesday or Wednesday. All areas 5-10 miles
inland of the beaches will likely see high temperatures in the
100-110 range by Tuesday or Wednesday, with little change through
Friday or Saturday. The northerly shift in the flow means that the
hottest conditions will not be in the desert, but in the coastal
valleys. Expecting several calendar day records to fall. Overnight
conditions will be warm as well. The magnitude of the daytime
temperatures, the limited relief overnight, and the prolonged
nature of this heat event raises the bar to the high level in
terms of the risk for heat-related illness. The current suite of
Heat Advisories and Extreme Heat Watches looks good. Expecting
most of the areas, especially inland of the beaches, to be
upgraded to Extreme Heat Warnings by tomorrow or Tuesday, with
most of the rest of the area not covered (SLO and northern Santa
Barbara Counties) being added to the part with either Advisories
or Warnings.

Sundowner winds will affect southern Santa Barbara County through
the week, and should increase some each night. Wind Advisories
might be needed by Tuesday.

The shallow marine layer will likely keep low clouds and dense fog
on the Central Coast through Tuesday, but developing offshore flow
may either keep it off the coast after that or complete scour it
out. If that happens, expect temperatures to increase above
current projections (although they have been upped to better
account for this possibility). How the marine layer will behave
over Los Angeles and Ventura Counties is anyones guess at this
point. There are indications of a coastal eddy forming by Tuesday,
which increases the odds of some shallow low clouds at the coast,
but it is a really tough call.

.LONG TERM (WED-SAT)...23/300 AM.

The only real question for the Wed through Fri forecast is: will
it be very hot or extremely hot. This forceast problem is driven
by a wide range of possibilities with the sfc gradients. The EC is
show a fairly strong offshore push which would bring near record
very dangerous heat to the area. The GFS keeps the E/W gradient
onshore but even it has some offshore flow forecast from the north
(just much less than the EC does). The upper high moves a little
to the west but hgts really do not change much and should remain
around 594 dam through the period.

Almost all of the vlys, lower mtn elevations and far interior will
have temps between 100 and 110 degrees during this period. If the
EC verifies Vly temps could end up 2 to 3 degrees warmer than the
current forecast. The interior cst sections (such as DTLA) have a
15 percent chc of high temps of 100 to 103 degrees. The Central
Coast will not be immune from the heat this time around. Offshore
trends will lead to an 8 to 12 degree warm up on Wednesday leading
to max temps in the upper 80s to mid 90s - there is a 10-20
percent chc that SLO could see 100 degrees.

In addition to the daytime highs overnight lows will be 8 to 12
degrees above normal and this will greatly exacerbate the heat
risk as there will be no time for people`s body to release the
heat stress.

It is very likely that almost the entire forecast area will be
blanketed by some combination of heat advisories and Extreme Heat
Warnings starting Wednesday.

One additional local concern will be very hot sundowners across
southern SBA county. A decent N to S gradient will set up over the
county each evening and gusty north canyon winds will develop.
These hot winds could drive max temps into the 100-105 degree
range and could also keep temperatures in the 80s until almost
dawn.

Some cooling is forecast on Saturday, but in the past these heat
waves have held on a little longer than forecast.

&&

.AVIATION...24/0025Z.

At 2327Z at KLAX, the marine layer was 500 feet deep. The top of
the inversion was at 2500 feet with a temperature of 30 degrees
Celsius.

For the 00Z TAF package, high confidence in KPRB, KSBA, KOXR,
KCMA, KSMO, KWJF and KPMD.

For KSBP, there is a 40-50% chance that CIG/VSBY restrictions do
not develop tonight. For KSMX, timing of flight category changes
could be +/- 2 hours of current forecast, with a 20% chance of
brief or no CIGs forming.

For KLAX and KLGB, there is a 10-20% chance of LIFR/IFR conditions
08Z-17Z.

KLAX...Overall, good confidence in 18Z TAF. There is a 20% chance
of LIFR/IFR conditions 08Z-17Z. No significant easterly wind
component is expected.

KBUR...High confidence in the 00Z TAF.

&&

.MARINE...23/806 PM.

For the Outer Waters, high confidence in current forecast. Tonight
through Friday, Small Craft Advisory (SCA) winds are expected to
continue although the winds will drop briefly across PZZ670
tonight and Monday. Short period SCA level seas (5 to 7 feet at
6-8 seconds) will continue along with the gusty winds. Wednesday
into Thursday, larger seas approaching 7-9 feet are likely.

For the Inner Waters north of Point Sal, moderate to high confidence
in current forecast. Tonight through Monday night, high confidence
in winds and seas remaining below SCA levels. For Tuesday through
Friday, there is a 50-70% chance of SCA level winds each afternoon
and evening.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For a majority of the southern
Inner Waters, high confidence in winds and seas remaining below
SCA levels through Friday. The only exception will be the western
half of the Santa Barbara Channel where there is a 60-80% chance
of SCA level winds Monday through Friday, mainly in the late
afternoon and evening hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory in effect until 10 AM PDT Tuesday for zones
      38-87-88-349>358-362-366>376-378>380-548. (See LAXNPWLOX).
     Extreme Heat Watch in effect from Tuesday morning through
      Friday evening for zones
      38-87-88-349>358-362-366>376-378>383-548. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 4 AM PDT Tuesday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...RK/Rorke
AVIATION...Ciliberti
MARINE...RAT/Ciliberti
SYNOPSIS...RK

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office