338
FXUS66 KLOX 152138
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
238 PM PDT Sat Aug 15 2026

.SYNOPSIS...15/237 PM.

Night through morning marine layer clouds will continue for the
coast and valleys, shrinking in coverage each day into next week.
Cooler than normal temperatures continue through this weekend,
then warmer than normal temperatures return next week, with
widespread moderate Heat Risk potentially occurring away from
the immediate coast.

&&

.SHORT TERM (TDY-TUE)...15/159 PM.

Weak upper level trough of low pressure off the coast of
California today combined with moderate onshore flow has
resulted in another deep marine layer this morning, along with
cooler than normal daytime temperatures. The marine layer
depth was between 2500 and 3000 feet this morning. Other than a
few cloud build-ups over the local mountains each afternoon this
weekend, looking for all thunderstorm activity to remain well
south and east of our area.

The main story over the next seven days is the warming and drying
trend, with increasing confidence that heat will likely peak
in the Tuesday through Friday time frame. The large area of high
pressure will continue to expand west over the next few days,
nudging in higher 500 mb heights each day, reaching 596 dm by
Tuesday. In addition, we will get slight weakening of the onshore
pressure gradient by Monday or Tuesday, along with the marine
layer depth becoming more shallow with time. Temperatures are
expected to ramp up by Tuesday, when many valley, lower mountain,
and desert locations could reach 90-102 degrees, leading to a
moderate chance of a heat advisory.

An increase in northwest to northerly winds is likely as soon as
Sunday afternoon/evening as the north-south pressure gradient
strengthens. We will see increasing gusty winds over southwest
Santa Barbara County and interior mountains (especially through
the Grapevine) and the Antelope Valley. At this point winds aren`t
expected to be widespread advisory levels, however, there is a
moderate chance for advisory level winds across southwest Santa
Barbara County by Monday evening, as the Santa Barbara-Santa Maria
gradient is expected to peak around -4 mb. The focus of the winds
each evening will be from Gaviota to San Marcos Pass, with
isolated gusts up to 45 mph near Gaviota/Refugio on Monday
evening.

.LONG TERM (WED-SAT)...15/236 PM.

There is now good agreement amongst models that the upper level
ridging will remain over the Western US, bringing hot and dry
conditions to Southwest California Wednesday through Friday.
Boundary layer temperatures continue to edge upward during this
period, with further weakening of the onshore pressure gradients.
During this time period, there is increasing confidence that
high temperatures will peak in the 93-105 degree range for
valleys, lower mountains, and deserts. In addition, the weakening
of the onshore gradients will likely allow heat to expand into
the inland portions of the coastal plain. Downtown LA will likely
climb in the 90 to 95 degree range during this time. With these
projected temperatures, there is moderate confidence that heat
advisories will be issued for many areas away from the immediate
coast at some point between Tuesday and Friday. Ensemble data
shows less certainty in the upper level pattern and resultant
temperatures for next weekend. There is still the potential for
the hot and dry pattern to extend into next weekend, but
definitely less confidence than Tuesday-Friday. Overnight lows
will also start to warm in the extended period, especially in
the foothills and lower mountains, which will add to the heat
discomfort.

This long duration of hot and dry weather will bring widespread
elevated fire weather conditions away from the coast next week,
with the potential for large vertical plume growth across the
interior. The marine layer is expected to be fairly shallow,thus
dense fog may become an issue in some coastal areas. The north-
south pressure gradient will allow for weak to potentially
moderate Sundowner winds across southwest Santa Barbara county,
with Friday night likely being the best chance for moderate winds.
Aside from gusty winds across southwest Santa Barbara County,
interior mountains and desert will likely see an uptick in
northwest to north winds overnight.

&&

.AVIATION...15/1942Z.

At 1811Z at KLAX, the marine layer was at 2000 feet deep. The top
of the inversion was near 3100 feet with a temperature of 21 C.

High confidence in VFR TAFs for KPMD & KWJF.

Moderate confidence in remaining TAFs. Arrival of CIGs tonight
may be off +/- 4 hours, lowest confidence in timing for KSBA,
KOXR, KCMA. Low chance for brief LIFR cigs at KSBP/KSMX/KPRB.
There is a 30% chance of KPRB remaining VFR through the period.
There is a 30% chance of IFR conds at KLAX, KSMO, KLGB, KBUR, and
KVNY 08Z-16Z Sun.

KLAX...Moderate confidence in TAF. CIG arrival time may be
between 03Z-08Z. There is a 30% chance of BKN008 conds 03-16Z Sun.
No significant east wind component expected.

KBUR...Moderate confidence in TAF. There is a 30% chance for
BKN008 conds 08-16Z Sun.

&&

.MARINE...15/230 PM.

Moderate to high confidence in forecast. There is a 40-60 percent
chance of Small Craft Advisory (SCA) level winds developing over
the outer waters from near Point Conception southward to San
Nicolas Island and in the vicinity of the Channel Islands this
afternoon through late night. Further north over PZZ670, there is
a 30-40 percent chance of SCA gusts from late this afternoon
through late tonight.

There is a better chance of SCA level winds developing Sunday
afternoon from near Point Conception and southward over the outer
waters, and over the nearshore waters inside the S CA Bight. These
nearshore winds are likely to subside early Monday morning, but
with SCA winds continuing over the two southern outer zones
PZZ673-676. By late Monday afternoon or evening, SCA winds are
likely to expand northward to the outer and nearshore waters north
of Pt. Sal, and into the Santa Barbara Channel. Local gusts to 25
knots may affect portions of PZZ655 Monday evening.

Strong SCA winds are likely to persist over the outer waters
Tuesday and Wednesday, affecting the nearshore areas in the
afternoon and evening hours. Local gale force gusts will be
possible during this time. In addition, building short period
seas are expected, likely rising to around 8 feet over the outer
waters.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Lewis
AVIATION...Lund
MARINE...Ciliberti/KL
SYNOPSIS...Lewis

weather.gov/losangeles

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