Acton Weather

166
FXUS66 KLOX 130930
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
230 AM PDT Wed May 13 2026

.SYNOPSIS...13/229 AM.

Temperatures will largely be below normal today, with low clouds
widespread during the morning. Chances are high for sunshine at
the beaches by the afternoon. Gusty winds are expected times
across the mountains and deserts. Slight warming is expected
Thursday and Friday, and above normal temperatures are possible
early next week.

&&

.SHORT TERM (TDY-FRI)...12/1104 PM.

***UPDATE***

Continuing to see a significant disparity in temperatures from
the coasts locked under marine layer clouds and the sunny inland
areas. Marine layer clouds reached deep into the valleys supported
by a strong onshore LAX-DAG gradient, and clouds kept the high
temperatures in the cool upper 50s to low 70s. High temperatures
tomorrow should be quite a bit colder over the interior tomorrow
as flow shifts back to northwest over the region. This should
scatter out the marine layer later on Wednesday, however, still
expecting plenty of morning marine layer clouds pushing deep into
the valleys, so will likely need to decrease temperatures near the
coasts for Wednesday. Otherwise, the forecast looks on track.

***From Previous Discussion***

The marine layer has deepened significantly since yesterday,
accounting for nearly all of the cooling trends over this time
especially for coastal valleys. Low clouds will likely stick
around most of the day for many areas west of the mountains thanks
to strong onshore flow and strong inversion. Isolated mid level
clouds have started to develop over some interior mountains. This
is evidence of the weak moisture intrusion from the southeast that
will support about a 5 percent chance of a shower or thunderstorm
to interior mountains and valleys, especially northern Ventura
into northeast Santa Barbara Counties. Dry lightning fire starts
and gusty winds would be the greatest concern if a thunderstorm
were to form.

A weak trough passing overhead will boost the marine layer
another 1000 feet or so to 3000-4000 feet into Wednesday. Sending
the cooling trends experienced today further inland with
temperatures near normal for this time of year. The additional
deepening may support spotty drizzle especially into foothill to
lower mountain locals. One more day of slow to no clearing of low
clouds is likely Wednesday, especially into the coastal slopes as
a reverse clearing (clearing at the coast before the
valleys/foothills) day is possible.

Breezy northwest to southwest winds will is expected afternoon to
evening, possibly boosting to near advisory levels for areas prone
to northwest winds (southwest Santa Barbara County & I-5 corridor
in the mountains) Wednesday evening and again as early as Friday
afternoon.

Weak ridging building into the region will likely shrink the
marine layer closer to the coast and lead to warming trends
Thursday and Friday, but no where near the heat we saw just
yesterday.

.LONG TERM (SAT-TUE)...12/1256 PM.

Below normal confidence this weekend into early next week as a
sharp trough (for May) is poised to pass nearby. An inland track
(50 percent chance) would lead to near normal temperatures with
breezy winds nearing advisory levels for some interior areas such
as the mountains near the I-5 corridor and southwest Santa Barbara
County into Saturday or Sunday with the potential for offshore
winds with decent warming and drying trends into Monday. A close
pass (30 percent chance) would lead to gusty and probably advisory
northerly winds for the interior and mostly below normal
temperatures.

&&

.AVIATION...13/0913Z.

At 0702Z at KLAX, the marine layer was 2700 ft deep. The top of
the inversion was at 4500 ft with a temperature of 19 C.

High confidence in VFR conditions at KPMD & KWJF through at least
Tuesday. High confidence in ceilings at all other airports
tonight into Tuesday, with MVFR most common. Brief IFR ceilings
are possible almost everywhere 10-15Z.

KLAX...Moderate confidence through 18Z Tuesday in ceiling category
and timing (plus or minus 3 hours). Low confidence on timing of
any clearing. High confidence in any east winds staying under 8
knots.

KBUR...Moderate confidence in ceiling category and timing (plus
or minus 3 hours). High confidence in any east winds staying
under 8 knots.

&&

.MARINE...13/215 AM.

For the outer waters from the Central Coast to San Nicolas
Island, high confidence in Small Craft Advisory (SCA) winds and
seas developing Wednesday and lasting through at least Thursday
Night, except for a a likely brief break Wednesday 9am to 2pm.
Moderate risk of Gale Force winds as early as Friday and peaking
over the weekend, with large 10+ foot steep seas.

SCY conditions likely for the nearshore Central Coast waters
each afternoon and evening through Thursday, with stronger winds
and building seas Friday through the weekend.

Winds will stay under SCY for all other waters through at least
Thursday, with a moderate risk of SCY conditions by the weekend.

Over the weekend...The combination of high winds and seas could
result in hazardous surfing conditions and minor coastal flooding
especially across more unprotected west-facing beaches such as
along the Ventura coastline. Stay tuned for future updates.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 9 AM this morning to 9 AM
      PDT Thursday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 9
      AM PDT Thursday for zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 6 PM this evening to 9 AM
      PDT Thursday for zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Phillips/Munroe
AVIATION...Schoenfeld
MARINE...RK
SYNOPSIS...MW/RS

weather.gov/losangeles

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