148
FXUS66 KLOX 232047
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
147 PM PDT Sun Aug 23 2026
.SYNOPSIS...23/1251 PM.
Very hot temperatures are expected this week with highs 6-12
degrees above normal. Patchy night through morning low clouds and
fog will be confined to coastal areas, mainly north of Point
Conception.
&&
.SHORT TERM (TDY-WED)...23/142 PM.
All signs still pointing towards a very hot week, especially south
of Pt Conception. The combination of strong high pressure aloft,
weakening onshore flow, and much warmer than normal ocean
temperatures will create a long duration heat event, during which
several daily records will likely be broken. The warmer than
normal SST`s will primarily impact the overnight temperatures,
keeping those higher than normal and hindering any beneficial
cooling. Heat advisories are in affect for most areas south of Pt
Conception through Monday night with minimal changes in
temperatures Monday over today. However, models have been
consistent showing a 2-5 degree increase in highs Tuesday and
Wednesday pushing some areas into the major heat risk category.
The biggest factor determining which areas get upgraded to an
Extreme Heat Warning will be the pressure gradients and will wait
to see how those look with Monday`s model runs. Currently there is
a 30-40% chance of highs of 110 or higher in the San Fernando
Valley and a 50% chance of highs of 100 or higher in Downtown LA.
For the Central Coast, the case for heat advisories is not as
strong though by Tuesday or Wednesday low end advisories would
likely be appropriate for inland coastal areas like Santa Maria
and San Luis Obispo as well as the Salinas Valley.
.LONG TERM (THU-SUN)...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...23/1615Z.
At 1600Z at KLAX, the marine layer was 500 feet deep. The top of
the inversion was at 2700 feet with a temperature of 28 degrees
Celsius.
For 18Z TAF package, high confidence in KPRB, KSBA, KOXR, KCMA,
KSMO, KWJF and KPMD.
For KSBP, there is a 50% chance that CIG/VSBY restrictions do not
develop tonight. For KSMX, timing of flight category changes could
be +/- 2 hours of current forecast.
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 10-20%
chance of LIFR/IFR conditions 08Z-17Z. No significant easterly
wind component is expected.
KBUR...High confidence in 18Z TAF.
&&
.MARINE...23/110 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. Seas will be approaching SCA levels beginning
on Wednesday.
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 30% chance of
SCA level winds late this afternoon and evening then 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 9 PM PDT this evening
for zone 670. (See LAXMWWLOX).
Small Craft Advisory in effect until 4 AM PDT Tuesday for
zones 673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...MW/Rorke
AVIATION...RAT
MARINE...RAT
SYNOPSIS...MW
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
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