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628
FXUS66 KLOX 231210
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
510 AM PDT Thu May 23 2024

.SYNOPSIS...23/248 AM.

Strong onshore flow and a deep marine layer will keep the night
through morning low clouds and fog pattern going with low clouds
reaching the foothills each day. There will be patchy drizzle each
morning. The near shore area will see limited or no clearing through
Saturday. High pressure will bring better clearing and warmer
temperatures to the area starting Sunday and continuing into next
week.

&&

.SHORT TERM (TDY-SAT)...23/332 AM.

The marine layer has deepened to 2800 ft and moderate to strong
onshore flow has pushed the low clouds over the csts/vlys and
deep into the mtn passes and foothills. There will be enough lift
near the foothills to produce patchy drizzle. Strong onshore flow
will bring slow clearing to the vlys, slow to no clearing for the
interior coastal sections and no clearing to many if not most
beaches. Max temps will be similar to ydy xcp for the Central
Coast where a little thinning marine layer cloud deck will allow
for some warming. The strong onshore flow will bring advisory
level gusts to the western Antelope Vly foothills and stronger
than normal afternoon winds elsewhere. Max temps will end up 5 to
10 degrees blo normal.

A fairly sharp trof embedded in the broad cyclonic flow will move
over the state on Friday. It will further deepen the marine layer.
Low clouds again will cover all the csts/vlys/foothills and mtn
passes. The trof will bring enough lift to generate areas of
drizzle even away form the foothills. There is even a slight chc
of light rain esp near the foothills. The most likely outcome for
the afternoon will be another day of slow to no clearing there is,
however, a 30 percent chc that the trof along with its attendant
cold air will mix the marine layer out and make it a sunny
afternoon. The trof axis will move over the mtns in the afternoon
and it is vigorous enough to bring a slight chc of a mtn shower.
The strong (~10 mb) W to E push will bring advisory level winds to
the western Antelope Vly and foothills and will likely bring
advisory level winds to many other mtn/interior. Cst/Vly temps
will not change much but the cool air behind the trof will cool
the interior by 4 to 8 locally 10 degrees. Max temps will only be
in the 60s across the csts/vlys and in the 70s for the interior.
These max temps are mostly 10 to 15 degrees blo normal.

Less confidence in the Saturday forecast which currently call for
a continuation of the low cloudiness. There is a chance (40
percent) that the marine inversion will be mixed out and skies
will be much clearer/sunnier than currently fcst. If there are
morning low clouds, offshore trends should make for faster
clearing although some beaches may remain cloudy. Max temps will
warm some but hgts will not have recovered enough to bring
anything more than a couple of degrees.

.LONG TERM (SUN-WED)...23/347 AM.

The GFS and ECMWF and their respective ensemble means continue to
remain in good agreement through Tuesday. On Sunday the
broad west coast trof will finally push to the east and will be
replaced by a weak ridge. Hgts will rise from 577 dam to ~584 dam
on Tuesday. The onshore flow will weaken and the N to S gradient
may even turn briefly offshore.

The night through morning low cloud pattern will continue but the
higher hgts will push the marine layer down and this along with the
weaker onshore push will limit the vly penetration. N to S
offshore flow across the SBA south coast may keep that area clear
through the period. The low clouds will clear earlier and more
completely all three days.

The residual cool air will no longer exist in the interior and
that will allow a 5 to 10 degree warm up across the interior on
Sunday while the csts/vlys will warm 2 to 4 degrees. Then as hgts
continue to rise look for about 2 to 4 degrees of warming each day
Mon and Tue. Max temps on Tuesday will finally come within a few
degrees either side of normals.

While not in the best of agreement the mdls and ensemble favor a
return to upper level troffing and stronger onshore flow. Look for
an increase in marine layer coverage and slow down in clearing as
well as downward trend in temperatures.

&&

.AVIATION...
-- Changed Discussion --
23/1209Z.

At 11Z at KLAX, the marine layer was 3200 ft deep. The top of the
inversion was at 7100 feet with a temperature of 15 C.

High confidence in desert TAFs.

Moderate confidence in remainder of TAFs. Widespread low clouds in
coastal and valley areas this morning, all the way to the coastal
slopes and into interior sections of SLO County. Conds were
mostly low MVFR to IFR, except LIFR to VLIFR in the Santa Ynez
Valley and in the foothills/mtn slopes. Expect slow clearing today
with little if any clearing near the coast south of Pt.
Conception. Skies should clear by mid to late morning in the
valleys and early to mid afternoon on the coastal plain, with
clouds likely lingering at the beaches. Expect widespread low
clouds in coastal and valley areas tonight and all the way to the
coastal slopes. Conds will be mostly MVFR to high IFR, except
LIFR to VLIFR conds in the foothills/mtn slopes.

KLAX...Moderate confidence in TAF. There is a 20-30% chance that
cigs will scatter out between 20Z today and 02Z Fri. High
confidence in any east wind component remaining less than 6 kt.

KBUR...Moderate confidence in TAF. There is a 20% chance that cigs
could linger thru 22Z or scatter out as early as 18Z. There is a
20% chance that cigs tonight will not arrive until 07Z or later.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
23/458 AM.

In the outer waters, Small Craft Advisory (SCA) level winds will
continue much of the time thru Sun night. Winds may drop below SCA
levels late Sat night/Sun morning. There is a 40% chance of SCA
level winds Mon.

In the inner waters N of Pt. Sal, there is a 30% chance of SCA
level winds this afternoon/eve. SCA level winds are likely (70%
chance) in the afternoon/eve hours Fri and Sat. There is a 30%
chance of SCA winds during the afternoon/eve hours Sun and Mon.

In the SBA Channel and southern inner water, there is a 40% chance
of SCA level winds in western portions of the SBA Channel this
afternoon/eve. SCA level winds are likely (70% chance) in western
portions of the SBA Channel in the late afternoon thru late night
hours Fri and Sat. Otherwise, SCA conds are not expected thru Mon.
-- End Changed Discussion --

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 2 PM this afternoon to 9 PM PDT
      this evening for zone 381. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB
SYNOPSIS...30

weather.gov/losangeles

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