539
FXUS66 KLOX 131728
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Thu Aug 13 2026

UPDATED AVIATION SECTION

.SYNOPSIS...13/108 AM.

Cooler than normal temperatures and widespread marine layer
clouds will continue through the weekend. There is a low chance of
showers/thunderstorms through this afternoon.

&&

.SHORT TERM (TDY-SAT)...13/807 AM.

The latest water vapor imagery indicates a weak trough of low
pressure aloft moving into the Central Coast of California this
morning. A deep marine layer depth in place has pushed clouds into
the coastal slopes and in the interior valleys for areas north of
Point Conception this morning, and into the valley south of Point
Conception. Instability with trough has lifted the marine layer
cloud deck and squeezed out drizzle or light rain along the
Central Coast this morning. PoPs have been nudged up in the latest
update and mentions of more widespread showers added to the
forecast for this morning. A cooling trend is expected to continue
across the region today.

***From Previous Discussion***

The trough along the coast has finally settled in. Mid-level
clouds are streaming in from the southwest, temperatures will
continue to cool, and there remains a small chance for convective
activity today.

The low chance of showers/thunderstorms continues through this
afternoon across the area, with highest chances (15% chance)
across the Central Coast as well as the northern Ventura/interior
Santa Barbara County mountains. While high resolution CAMs really
don`t show much in the way of reflectivity, there is fairly
widespread elevated instability associated with this trough
across Santa Barbara and SLO Counties, as well as some left over
monsoonal moisture to play with through later this morning. A
small lobe of vorticity is projected to swing across the northern
part of our CWA now through this morning. This could be the best
opportunity for storm initiation through the day, although
afternoon heating and orographics could be the best source across
the interior areas. At lower elevations, the more significant
impacts could be gusty winds and dry lightning, while higher
terrain would potentially see higher rainfall rates--although not
expecting storms of the same magnitude as Tuesday`s storms. Very
low chances for showers/thunderstorms exist into the weekend as
the trough remains almost stationary along the coast. However,
the environment will become rather mositure starved, so not
expecting much in the way of rainfall if any storms get going.

Aside from the small chance for storms to develop, the most
significant aspect of the forecast is the continued cooler than
(mid-August) normal temperatures region-wide. Thanks the the
lower 500 mb heights brought along by the trough as well as
moderate to strong onshore flow, a very long stretch of above
normal temperatures has ceased. Friday`s max temps are forecast
to be very similar to today, around 8-15 degrees above normal in
many places. We are expecting a couple degrees of warming on
Saturday, but still well below seasonal normals.

A very deep marine has already expanded to many valleys. Fairly
similar coverage is expected Friday, with slightly less coverage
Saturday due to a shrinking marine layer depth. The marine layer
will burn off in the late morning to early afternoon, although
some west facing beaches may not see much in the way of clearing
as the onshore flow will try to keep the clouds in place.
Additionally, there is a chance for some patchy drizzle this
morning and again Friday morning. There is potential for mid
level clouds to disrupt the radiative cooling processes that help
the marine layer form. This could create more of a patchy marine
layer, with highest potential for this across LA and Ventura
Counties.

Enhanced onshore flow means fairly gusty west to southwest winds
will be common across the interior, with winds likely the
strongest across the Antelope Valley and foothills. While some
advisory level wind gusts may occur, not expecting these winds to
be widespread enough to warrant an advisory at this time.

.LONG TERM (SUN-WED)...13/104 AM.

The extended period will generally feature rather benign sensible
weather relative to the time of year. The upper level ridge of
high pressure over the southern United States will push the trough
to the west. 500 mb heights will increase to around 592-594 dam
with dry southwest flow aloft. 500 mb heights are projected to
peak Tuesday/Wednesday. Additionally, onshore flow is expected to
weaken some to some, with the LAX-BFL pressure gradient even
forecast to become negative by next week.

Marine layer clouds will shrink each day with increasing 500 mb
heights and weakening onshore flow, likely retreating to just the
coastal areas by early next week. By Tuesday, increasing northwest
flow will likely wipe out the marine layer from southern Santa
Barbara County and potentially Ventura County.

With 500 mb heights increasing, onshore flow weakening, and marine
layer coverage shrinking, temperatures will climb to near normal
for mid-August. The more noticeable increase in temperatures will
be across the valleys and interior since most coastal areas will
still be under marine influences.

Increasing northwest flow next week will likely bringing gusty
winds in the afternoon through late evening hours to Southwestern
Santa Barbara County as well as the interior mountains,
especially along the I-5 through the Grapevine.

&&

.AVIATION...13/1727Z.

At 1612Z at KLAX, the marine layer was 2900 feet deep. The top of
the inversion was near 4500 feet with a temperature of 18 C.

High confidence in VFR TAFs for desert airfields (KPMD & KWJF).

Moderate confidence in remaining TAFs. Timing of change groups
may be off +/- 2 hours. Expecting little to no clearing of MVFR
CIGs 015 to 030 excluding KBUR/KVNY. No clearing is most likely
for KSBP and KSMX (80% chance).

KLAX...Moderate confidence in TAF. Clearing of MVFR CIGs 025-030
likely around 13/20Z. MVFR CIGs expected to return around 14/01Z
(+/- 3 hours). There is 30% chance of no clearing. No significant
east wind component expected

KBUR...Moderate confidence in TAF. No wind issues expected

&&

.MARINE...13/738 AM.

High confidence that conditions will remain below Small Craft
Advisory (SCA) criteria across all coastal waters through Friday
morning. Low to moderate chances for SCA winds across favored
areas south of Point Conception this weekend. Increasing chances
across all coastal waters heading into next week, with local
gusts of 30-35 kt possible at times around Point Conception.
Seas may approach 10 ft across portions of the Outer Waters
Tuesday and Wednesday.

There is a very small chance of a shower nearshore from Point
Conception to the north through this morning.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Hall/Lewis
AVIATION...Black
MARINE...Black
SYNOPSIS...Lewis

weather.gov/losangeles

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