-- Discussion containing changed information from previous version are highlighted. --
014
FXUS66 KLOX 182132
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
232 PM PDT Tue Jun 18 2024

.SYNOPSIS...
-- Changed Discussion --
18/208 PM.

Onshore flow in place will keep temperatures near seasonal levels
across the region through Thursday. Night through morning low
clouds and fog will continue to be persistent across the coastal
and valley areas. A warming trend will establish on Friday with
above normal temperatures developing across the valleys,
mountains, and desert through the weekend and into early next week.
Dangerously hot weather is possible across the interior on Saturday
and Sunday.
-- End Changed Discussion --

&&

.SHORT TERM (TDY-FRI)...
-- Changed Discussion --
18/231 PM.

Low clouds and fog have mostly cleared away from the coast this
afternoon as onshore flow has weakened substantially versus
yesterday. Offshore flow tried to push down into the valley
areas, but the marine layer depth remained wedged in across the
Los Angeles Basin.

A broad upper-level trough of low pressure over the western States
will keep an onshore flow pattern in place, likely strengthening
into Wednesday as offshore push weakens. This will bring some
cooling to the region and take most areas back down to near normal
for this time of year. A return of coastal stratus is expected
tonight through Wednesday for most areas south of Point
Conception. The marine layer depth will thin some into Wednesday
and Thursday as 500 mb heights climb slightly, but in general, an
onshore flow pattern should keep low clouds and fog a staple of
the weather for the coastal and valley areas through Thursday.

A northerly surface pressure gradient across the region the last
several days will continue to wane. A wind advisory was allowed to
expire through the Interstate 5 Corridor earlier, but gusty
Sundowner winds will continue over the coming afternoons and
evening. A wind advisory remains in effect from this afternoon
through 3 am PDT tonight for the Southwestern Coast of Santa
Barbara County and the Santa Ynez mountains, but there is a
moderate-to-high chance that advisory level winds may develop
again on Wednesday afternoon and evening across the same areas.
Winds should weaken gradually each afternoon and evening as the
northerly gradient fades.

Onshore flow will weaken for late week as high pressure aloft over
the Eastern Seaboard today starts to slide closer to the region on
Friday. 500 mb heights will start to climb as upper-level
troughing vacates the region. A warming trend will take shape on
Friday and likely turn more significant over the weekend.

.LONG TERM (SAT-TUE)...18/231 PM.

High pressure aloft will continue to slide west through Sunday,
settling into the Desert Southwest while building to near 595
decameters on Monday. The latest forecast continue to break away
from NBM values to advertise hot conditions developing across the
region for the weekend. Dangerously hot conditions, if they were
to develop, would likely descend upon the Antelope Valley over the
weekend. Low confidence should be exercised in the low cloud
forecast as the coverage could be vastly overdone. Low clouds
could be confined to the coast over the weekend, which would warm
temperatures by a couple of degrees across the valley areas. Above
normal temperatures are likely to continue into early next week.
-- End Changed Discussion --

&&

.AVIATION...18/1756Z.

At 1715Z at KLAX, the marine layer was 2600 feet deep. The top of
the inversion was at 4500 ft with a temperature of 21 deg C.

Good confidence in TAFs for KPRB, KSBP, KSMX, KPMD and KWJF with
VFR conds expected thru the fcst period.

Moderate confidence in TAFs for KSBA, KOXR, KCMA, KSMO, KLAX,
KLGB, KBUR, KVNY. Any low clouds with MVFR conds at the start of
the TAF period should clear to VFR by 20Z. Low clouds and MVFR
conds are then possible at some point tonight into Wed morning.
The timing of the dissipation and onset of low clouds could be off
+/- and hour or two.

KLAX...Moderate confidence in TAF. There is a 30 percent chc of
clearing delayed until 20Z. Low cloud returns this evening may be
as early as 06Z or as late as 08Z. The low clouds should clear to
VFR by 20Z Wed. Any east wind component should be less than 6
knots.

KBUR...Moderate confidence in TAF. There is a 30 percent chc of
clearing delayed until 20Z. Low cloud should return this evening
by 08Z then persist thru 18Z Wed. The timing of the dissipation
and onset of low clouds could be off +/- and hour or two.

&&

.MARINE...
-- Changed Discussion --
18/115 PM.

For the Outer Waters, high confidence in current forecast. Small
Craft Advisory (SCA) Winds are expected through Thursday night
and perhaps as late as Friday night. Conditions are then expected
to be below SCA levels Saturday through Sunday night.

For the Inner Waters north of Point Sal, high confidence in
current forecast. SCA level winds will persist through Thursday
night, likely strongest during the afternoons and evenings. For
Friday through Sunday night, winds and seas should remain below
SCA levels.

For the inner waters south of Point Conception, moderate to high
confidence in current forecast. For the western Santa Barbara
Channel, winds gusts will be at SCA levels each afternoon and
evening through Thursday. Elsewhere and otherwise over the
southern inner waters, winds and seas should remain below SCA
levels through Sunday night.
-- End Changed Discussion --

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CA...Wind Advisory remains in effect until 3 AM PDT Wednesday for
      zones 349-351-352. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PDT this evening for
      zones 376>379. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Thursday for
      zones 645-670-673-676. (See LAXMWWLOX).
-- End Changed Discussion --

&&

$$

PUBLIC...Hall
AVIATION...Sirard
MARINE...Sirard
SYNOPSIS...Hall

weather.gov/losangeles

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