Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 241318
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
618 AM PDT Wed Apr 24 2024

.SYNOPSIS...24/233 AM.

Strong onshore flow and a deep marine layer will maintain much
cooler than normal temperatures across much of Southwest
California through at least Friday. Areas of night through
morning low clouds with patchy fog and drizzle are expected
across the coast, valleys, and foothills, with only partial
afternoon clearing. Warmer weather is expected by the weekend into
early next week.

&&

.SHORT TERM (TDY-FRI)...24/311 AM.

The next three days will be all about how the marine layer low
cloud pattern develops and dissipates each night and morning.
Synoptically a broad upper trof will move over the area today
followed by fast NW flow Thursday and then a fast moving inside
slider on Friday. The onshore flow will weaken each day with
diurnal afternoon maxes to the east about 8 mb today, 7 tomorrow
and 6 on Friday. The corresponding push to the north will be 2,
then 1 with Friday`s gradient switching to about a mb offshore.

The one thing to watch today is the trof that the mdls are not
impressed with. Satellite shows a slightly stronger looking system
that has even produced a lightning strike in the last two
hours. That said it looks like the bulk of this trof`s energy is
going to pass to the south.

Low clouds currently cover most of the csts/vlys with a notable
exception of the SBA south coast and the VTA coast. The low clouds
will likely move over the VTA coast but expect the SBA south cst
to remain clear. The capping inversion is very weak and this
combined with the deep marine layer should result in decent
coastal clearing for the coasts and partly cloudy skies due to
strata cu formation in the vlys. With similar cloud condition as
ydy the lower hgts from the approaching trof should bring a few
degrees of cooling to most areas. Max temps today across the
csts/vlys will be in the 60s or 6 to 12 degrees blo normal.

The trof moving over the area late this afternoon and evening
should deepen the marine layer again there will be enough lift to
produce some patchy evening drizzle. With the offshore trends esp
from the north there should be decent clearing Thursday afternoon.
The csts/vlys will respond to the additional sunshine and weaker
sea breeze with 1 to 3 degrees of warming but residual cool air
from the trof will cool the interior 3 to 5 degrees.

On Thursday evening/Friday morning the lift from the inside
slider should somewhat counter act the offshore trends in the sfc
gradients and bring low clouds to much of the csts/vlys but it
does look like the the VTA and South SBA csts will be clear. Some
north flow will bring clouds to the north slopes near the Kern
County line. The NW-N flow from the inside slider will bring near
advisory level winds to the northern LA mtns and portions of the
Antelope Vly. The developing offshore flow from the north should
bring total clearing. The offshore flow form the north, plenty of
sunshine will bring 3 to 6 degrees of warming to most areas. Max
temps will still mostly be 4 to 8 degrees blo normal.

.LONG TERM (SAT-TUE)...24/319 AM.

Xtnd mdls and ensembles are all in good agreement that weather
will take decidedly clearer and warmer turn for the weekend and
Monday. A ridge will move into and over the state hgts will reach
about 578 dam Sunday and might hit 580 dam on Monday. There will
only be weak onshore flow to the east and 2 to 4 mb of offshore
flow from the N. Skies should be clear through the period. Max
temps will rise 2 to 4 degrees each day. Monday`s Max temps will
be in the 70s and lower 80s or a few degrees above normal.

The ridge is forceast to break down on Tuesday and onshore flow
will increase. There might be some patchy low clouds in the
morning. Max temps will cool a few degrees.

&&

.AVIATION...24/1316Z.

At 12Z at KLAX, the marine layer was 4100 feet deep. The top of
the inversion was at 4800 feet with a temperature of 11 C.

There were areas of low clouds from the coastal slopes to the
beaches, but with a weakening inversion, clouds were breaking up.
In general, cigs were mostly high MVFR to VFR, except IFR to VLIFR
in the foothills/mtns. Skies should clear in most areas by late
morning, but there may be some stratocu in the valleys/foothills
in the afternoon. Expect widespread clouds tonight from the
coastal slopes southward/westward, with generally high MVFR to
VFR cigs, except IFR to VLIFR conds in the foothills/mtns.

KLAX...Moderate confidence in TAF. Conds should be mostly VFR thru
the period, though there should be some cigs at VFR levels this
morning, and again this eve thru Thu morning. There is a 20-30%
chance of MVFR cigs 08Z-16Z Thu. No east wind component expected.

KBUR...Moderate confidence in TAF. Conds should be mostly VFR thru
the period, though there is a 20-30% chance of MVFR cigs thru 18Z
this morning, and after 08Z tonight.

&&

.MARINE...24/607 AM.

In the Outer Waters, good confidence that winds will reach Small
Craft Advisory (SCA) levels in the southern two zones (PZZ673/676)
this afternoon thru late tonight, with a 30% chance in the northern
zone. SCA conds are expected Thu afternoon thru Sun. There is a
50-60% chance of gales late Thu afternoon thru Sat.

For the Inner Waters N of Pt. Sal, moderate to high confidence in
the forecast. There is a 20% chance of SCA level NW winds this
afternoon/eve. SCA level winds are likely in the afternoon/eve
hours Thu-Sun. There is a 30% chance of gales Fri afternoon/eve.

In the Inner Waters S Pt Conception, moderate confidence. SCA conds
are likely in western portions of the SBA Channel during the
afternoon/eve hours today and Thu, with a 30% chance of SCA conds
from Anacapa Island to Malibu. SCA conds are likely in the SBA
Channel and much of the southern inner waters during the afternoon
thru late night hours Fri-Sun. There is a 30% chance of gales in
the western SBA Channel and near Anacapa Island Fri afternoon/eve.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Thursday for zones 650-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB
SYNOPSIS...MW/Smith

weather.gov/losangeles

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


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