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000
FXUS66 KLOX 251313
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
613 AM 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)...25/317 AM.

The marine layer is 3300 ft deep. There is strong onshore flow to
the east and weak but increasing onshore flow to the north. Marine
layer stratus cover most of the area save for the Antelope Vly and
the SBA south coast (due to N to S offshore flow). A weak trof
passed over the area last evening and now brisk NW flow is moving
into and over the state. The marine layer is so deep and the
capping inversion so weak that reverse clearing is likely today.
N to NW flow will be increasing through the day and its possible
that this will create a little better clearing than fcst. NW to W
flow will bring near advisory wind gusts to the mtns and the
western Antelope Vly. Higher hgts will bring some warming to the
Central Coast, while north flow will bring noticeable warming to
the SBA south coast. Residual cool air and the strong onshore push
will team up to cool most of LA and VTA county. It will be another
cool day with max temps 6 to 12 degrees blo normal.

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...25/1310Z.

At 12Z at KLAX, there was no true marine layer, but a moist layer
up to about 7000 feet.

Widespread clouds were affecting the forecast area except for the
Antelope Valley and the highest mtns. Conds were mostly low VFR
to high MVFR, except IFR to VLIFR in the foothills/mtns. Skies
should become partly cloudy in most areas by late morning. Even
where it stays cloudy, cigs should be in the VFR category, except
in the foothills and mtns, where IFR conds may persist. Expect
widespread clouds again tonight, but with a weakening inversion,
clouds may be less solid in nature. Expect high MVFR to VFR cigs
tonight, except IFR to VLIFR conds in the foothills/mtns. Gusty NW
winds will affect southern SBA County and the I-5 Corridor, with
gusty W winds in the Antelope Valley. There will be some LLWS and
turbulence, with mdt UDDF near the mtns.

KLAX...Moderate confidence in TAF. Conds are expected to improve
to VFR by mid morning. There is a 20% chance that MVFR cigs will
persist until 19Z-20Z. There is a 20% chance that cigs will scatter
out from 21Z today to 03Z Fri. There is a 20% chance that conds
will remain VFR tonight, with cigs above 3000 ft. No east wind
component expected.

KBUR...Moderate confidence in TAF. Conds are expected to improve
to VFR by noon. There is a 20% chance that cigs will rise into
the VFR category as early as 17Z. There is a 20% chance that cigs
will scatter out from 21Z today to 03Z Fri. There is a 20% chance
that conds will remain VFR tonight, with cigs above 3000 ft.

&&

.MARINE...25/611 AM.

In the Outer Waters, good confidence that winds will reach Small
Craft Advisory (SCA) levels this morning, or at least by early
afternoon. SCA level winds and seas will likely continue thru Mon.
There is a 20% chance of gales in the southern 2 zones (PZZ673/676)
this evening thru late tonight. There is a 60-70% 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, good confidence that winds will
reach SCA levels this morning or early this afternoon. SCA level
winds/seas will likely continue much of the time thru Mon. There
is a 50% 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 conds are likely in western
portions of the SBA Channel by noon, 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 645-670. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through Friday
      evening for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect from noon today to 9 AM PDT
      Friday for zone 650. (See LAXMWWLOX).
     Gale Watch in effect from Friday morning through late Friday
      night for zones 650-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Friday for zone 655. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through late
      Friday night for zone 655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Friday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB
SYNOPSIS...JLD

weather.gov/losangeles

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