906
FXUS66 KLOX 232020
AFDLOX

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

.SYNOPSIS...23/901 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-SUN)...23/112 PM.

Marine layer clouds still blanket non-mountainous areas of Los
Angeles and Ventura Counties, the Santa Barbara south coast, and
northern coastal San Luis Obispo County. The onshore flow and
extensive stratus have temperatures down several degrees from
yesterday.

The strong onshore flow will bring advisory level gusts to the
western Antelope Vly foothills (Lake Palmdale gusting to 38 mph
already) and stronger than normal afternoon winds elsewhere. Max
temps will end up 5 to 10 degrees blo normal.

On Friday a sharp trof embedded in the broad cyclonic flow will
move over the state, further deepening 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 from the foothills, and a slight chc (less than
25%) of light rain esp near the foothills. The trof axis will move
over the mtns in the afternoon and it is vigorous enough to bring
a slight (less than 20%) chc of a mtn shower.

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 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.

Saturday should bring 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.

On Sunday the broad west coast trof will finally push to the east
and will be replaced by a weakly building ridge. Hgts will rise
from 577 dam to ~580 dam on on Sunday. 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 a bit 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. The low clouds should clear earlier and more completely
than they did today. 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.

.LONG TERM (MON-THU)...23/119 PM.

Models continue to remain in good agreement through Tuesday.
European solutions keep a though down through central CA on Wed
and Thu while GEFS is less so, but in SoCal there is fairly good
agreement.

As hgts continue to rise under the building ridge through Tuesday
look for about 2 to 4 degrees of warming each day. Max temps on
Tuesday will finally come within a few degrees either side of
normals. Look for an increase in marine layer coverage and a slow
down in clearing as well as downward trend in temperatures on Wed
and Thu as the ridge flattens and an onshore flow pattern remains.

&&

.AVIATION...23/1759Z.

At 18Z at KLAX, the marine layer was 4000 ft deep. The top of the
inversion was at 5000 feet with a temperature of 16 C.

High confidence in desert TAFs.

Low to moderate confidence in remainder of TAFs. Widespread MVFR
ceilings across coastal and valley areas this morning and some IFR
and LIFR ceilings near and over coastal mountain slopes. Clearing
will be slow today with little if any clearing near the coast
south of Pt. Conception, except partial clearing across the LA
Basin by afternoon. Valleys will clearing by mid afternoon.
Widespread MVFR low clouds will return/continue in coastal and
valley areas tonight, with some IFR to LIFR ceilings again near
the coastal mountain slopes.
KLAX...Low to moderate confidence in TAF. There is a 30-40%
chance that MVFR to low VFR cigs will continue all day. 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 longer. If cigs clear out this afternoon
there is a 20% chance that cigs tonight will not arrive until 07Z
or later.

&&

.MARINE...23/1040 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 waters, 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.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 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/jld
AVIATION...MW/DB
MARINE...MW/DB
SYNOPSIS...30

weather.gov/losangeles

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