000
FXUS66 KLOX 251905
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1205 PM PDT Thu Apr 25 2024

.SYNOPSIS...25/240 AM.

Strong onshore flow and a deep marine layer will keep temperatures
much cooler than normal across much of Southwest California
through Friday. Warmer weather is expected by the weekend into
early next week.

&&

.SHORT TERM (TDY-SAT)...25/853 AM.

***UPDATE***

A deep moist layer around 5000 ft thick covered the forecast area
this morning. Low clouds shrouded much of the region with only
parts of the SBA County S coast, the higher mtns and Antelope Vly
free of clouds. The clouds are expected to thin and scatter out
for much of the coast and a few adjacent vlys into the afternoon,
but overall should linger for much of the coastal slopes and
inland vlys.

During the afternoon, gusty mainly sub-Advisory level NW to N
winds are expected to affect the Central Coast, the southwestern
SBA County mtns and coast, he Antelope Vly including foothills,
and the L.A. County mtns along the I-5 Corridor. Otherwise, breezy
onshore winds can be expected this afternoon.

A cool air mass from a departing upper level trof will result in
afternoon temps today about 6-12 deg below seasonal norms.
Highs should only be in the 60s for much of the coast, vlys and
deserts.

***From Previous Discussion***

The north winds will increase today and advisory levels gusts
will develop in the early evening across the SW portion of SBA
county where a wind advisory is in effect from 6pm to 6am. Strong
winds will develop more slowly across the mtns and Antelope Vly
and wind advisories will likely be issued later in the day these
areas. The north flow will also bring upslope clouds and a slight
chc of showers to north slopes near the Kern County line. Low
confidence in the stratus forecast which may well be mixed out.
Right now betting on the the north winds to clear out most of VTA
county and the SBA south coast with cloudy conds across LA county
and the Central Coast.

Friday will be a breezy day as the NW flow reaches its maximum.
These winds will scour out the low clouds and will be a sunny day.
Advisory level gusts are likely for the Santa Ynez Mountains, VTA
mtns, northern I-5 corridor, and Antelope Valley. Look for 3 to 6
degrees of warming which will only make a small dent in the below
normal max temps.

A little inside slider will move down the CA/NV border Friday
night and will again bring a slight chc of N slopes showers to the
N slopes near the Kern county line. It will also reinforce the N
winds and advisory level northerly winds will likely continue
through dawn in the mtns and Antelope Vly with the strongest winds
focused through the I-5 corridor.

Saturday will see sunny skies and decreasing winds. 3 to 6 degrees
of warming will result from the offshore flow from the north, the
lack of marine layer, sunny skies and rising hgts.

.LONG TERM (SUN-WED)...25/326 AM.

Sunday and Monday will be very nice days with plenty of sunshine
and warming temps. All brought about by a weak ridge moving
overhead, weaker onshore flow to the east and continued offshore
flow from the north. Monday will likely be the warmest day of the
next 7 with highs in the 70s and lower 80s in the valleys and
upper 60s and 70s near the coast. These max temps will end up a
degree or 2 either side of normals.

Tuesday may have similar temps to Monday or it will cool some. It
all depends on how quickly the ridge breaks down and onshore flow
increases.

Troffing and increased onshore flow and a likely return of coastal
low clouds will ensure that Wednesday ends up about 4 degrees
cooler than Tuesday.

&&

.AVIATION...25/1858Z.

At 1742Z at KLAX, the marine layer was up to 5000 ft, and a weak
inversion with a top around 5900 ft and a temperature of 5 C.

Moderate confidence in TAFs. Today cigs will continue to clear and
lift until around 01Z Fri, then they will start to redevelop. Due
to a weakening inversion, clouds may be variable and scatter and
reform through the period. Expect mostly MVFR cigs tonight. Gusty
NW winds will affect southern SBA County and the I-5 Corridor,
and gusty W winds will continue and strengthen in the Antelope
Valley. LLWS and turbulence, with mdt UDDF near the mtns expected
starting, especially after 00Z Fri.

KLAX...Moderate confidence in TAF, with uncertainty in OVC015 cig
arrival timing/clearing. There is a 20% chance that conds will be
BKN035 or higher tonight. There is a 30% chance of east winds
reaching 8 kts from 08Z-14Z.

KBUR...Moderate confidence in TAF, with uncertainty in OVC015 cig
arrival timing/clearing. There is a 20% chance that conds will be
BKN035 or higher tonight.

&&

.MARINE...25/1202 PM.

In the Outer Waters, winds are mostly at at Small Craft Advisory
(SCA) level. SCA level winds and seas will likely continue thru
Mon. There is a 30% chance of gales in the southern 2 zones
(PZZ673/676) this evening thru late tonight. There is a 60-80%
chance of gales across all of the outer waters Fri morning or
early Fri afternoon thru late Fri night, best chances in the
southern 2 zones. There is a 50% chance that gales will occur
again Sat afternoon into Sat night or possibly Sun, especially in
the southern zones.

For the Inner Waters N of Pt. Sal, winds are just reaching SCA
levels. SCA level winds/seas will likely continue much of the
time thru Mon. There is a 50-70% chance of gales Fri
afternoon/evening, with a 30% chance of gales into Sat evening,
with a brief respite Sat morning.

In the Inner Waters S Pt Conception, SCA winds are occuring in
western portions of the SBA Channel, and spreading across the
rest of the Channel and into western portions of the southern
inner waters this afternoon. Winds may occasionally drop below SCA
levels late tonight or early Fri near the coast, then SCA level
winds and seas are expected from late Fri morning thru Sat night,
and most likely thru Mon. There is a 60-70% chance of gales Fri
afternoon into Fri night, with a 40-50% chance of gales Sat
afternoon into Sat night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 6 PM this evening to 6 AM PDT
      Friday for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Friday for
      zones 645-655-670. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through Friday
      evening for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Friday for
      zones 650-673-676. (See LAXMWWLOX).
     Gale Watch in effect from Friday morning through late Friday
      night for zones 650-673-676. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through late
      Friday night for zone 655. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke/Sirard
AVIATION...Schoenfeld
MARINE...DB/Schoenfeld
SYNOPSIS...JLD

weather.gov/losangeles

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