241
FXUS66 KLOX 161158
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
458 AM PDT Sat Aug 16 2025

UPDATED AVIATION SECTION

.SYNOPSIS...16/341 AM.

Below normal temperatures and low clouds over coasts and valleys
expected through Monday, with little day-to-day change. Gusty
Sundowner and I-5 winds will continue each night, with gusty
onshore winds over the deserts. High pressure will quickly build
over the region Tuesday through the end of the week with climbing
temperatures. Thursday looks the hottest, with many valleys and
lower mountains approaching or exceeding 100 degrees. Monsoonal
surges are also possibly by Wednesday or Thursday.

&&

.SHORT TERM (TDY-MON)...16/337 AM.

A persistant low over the Alaskan Panhandle, paired with stronger
than usual for August onshore flow/pressure gradients will change
little through Sunday or Monday. Temperatures will remain 5-10
degrees below normal as a result, with a faily deep and expansive
marine layer. Highs in the 70s will be common over coastal areas,
80s over the valleys, and 90s over the deserts.

Winds will remain gusty over southwest Santa Barbara County each
night, stronger Sunday and Monday nights when a low-end Wind
Advisory may be needed. Those nights will also see the winds
expand to the east and into the wind prone areas of the eastern
Santa Ynez Range. Gusty southwest winds also expected each
afternoon over the Antelope Valley and nearby foothills, as well
as northwest winds through the I-5 Corridor each evening, but
neither should not reach Wind Advisory levels.

.LONG TERM (TUE-FRI)...16/403 AM.

High pressure aloft, currently centered and parked over northeast
Texas, will quickly shift to the west around Tuesday and center
itself over the four corners by Thursday at 598 decameters. The
majority of the projections show little change after through the
end of the week. This major pattern shift will bring several
changes to our weather.

Temperatures will climb quickly, going from 5-10 degrees below
normal on Monday to around 10 degrees above normal by Thursday
(likely the warmest day). Confidence is high for this sharp
warming trend inland of the coasts, with fairly remarkable
consensus in the ensemble projections. To illustrate this, out of
the 50 EC ensemble temperature projections for Van Nuys, 45 of
them have a high temperature between 103 and 106 degrees for
Thursday. Thats a 3 degree variance more than 5 days out. Low
temperatures will also warm, with many areas in the mid 60s to
lower 70s, and foothill areas not dropping below the 80s or even
90s. At this point, there is a 70 percent chance for Heat
Advisories over many valleys and mountains Wednesday through
Friday, with a 20 percent chance of localized Heat Warnings over
the hottest valleys. The current NBM forecasts are far too low, so
pushed the official forecast closer to the 75th percentile NBM,
except at the coast due to the marine layer wildcard.

The marine layer will get squashed with patches of dense fog
likely. Determining the coverage of the low clouds this far out is
impossible. With that said, there are indicators that the marine
layer could dissipate or drastically shrink in coverage as onshore
pressure gradients weaken. This is especially the case on the
Central Coast where several models are showing locally breezy
northeast winds as early as Tuesday. If and where this ends up
dissipation happens, coastal temperatures will be higher than
currently projected. To quantify this potential, about 40 percent
of the EC ensembles have temperatures at or above 100 degrees for
San Luis Obispo, with about 20 percent at or below 90. If the
hottest outcome ends up happening, Heat Advisories would also be
needed for some select coastal areas.

The monsoonal potential is also rising for the middle to end of
the week thanks to the textbook several-day four corners position
of the high. While most models are not showing a lot of moisture
streaming up, most are showing precipitable waters going over 1
inch which is fairly healthy this far out. This looks to be the
best window for monsoonal thunderstorms of the season. Would be
surprised if we do not see at least one shower or thunderstorm
over the typical magnet areas like the eastern San Gabriels or the
northern Ventura Mountains.

&&

.AVIATION...16/1158Z.

At 1053Z at KLAX, the marine layer was 2800 ft deep. The top of
the inversion was at 4700 ft with a temperature of 21 Celsius.

High confidence in VFR TAFs for KPMD and KWJF with breezy SW
afternoon and evening winds.

Moderate to high confidence in TAFs for remaining sites. Dissipation
times may be off +/- 90 minutes. There is a 20% chance for no
clearing at coastal sites south of Point Conception. High
confidence in arrival of cigs again. Arrival times may be off +/-
2 hours, highest uncertainty for KSBA, KOXR, and KCMA. Minimum CIG
height may be 200 ft lower than forecast.

KLAX... High confidence in TAF. Clearing times may be between 19Z
and 22Z, however, there is a 20% chance for no clearing. Arrival
of cigs tonight may be as early as 00Z, with high confidence in
CIGs remaining above 012. There is a 30% chance for an east wind
component reaching 8 kts through 17Z.

KBUR...High confidence in TAF. Clearing time may be off +/- 90
minutes. Return of MVFR cigs tonight may be as early as 04Z.

&&

.MARINE...16/204 AM.

High confidence in seasonably gusty NW winds across the waters
beyond 20 miles from shore between the Central Coast to San
Nicolas Island. Small Craft Advisory (SCA) conditions will be
common into next week, except for some morning lulls. Brief and
very localized Gale Force gusts to 35 knots may occur in the
evening hours tonight and Sunday from Point Conception south to
San Nicolas Island. More widespread Gales may occur next week, as
early as Tuesday.

The nearshore Central Coast waters will see SCA level winds each
afternoon and evening into next week. Strongest winds today will
be focused from Pt Piedras Blancas to Cayucos Point in the late
afternoon to the evening hours.

The western Santa Barbara Channel will also see periods of SCA
conditions during the late afternoon and evening hours from
Saturday afternoon into next week. Winds look slightly stronger
with more spatial coverage for this afternoon and evening
compared to Friday, thus a SCA was issued.

All areas will see choppy seas from these winds in the late
afternoon through late night hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zones 645-650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Kittell
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...RK

weather.gov/losangeles

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