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796
FXUS66 KLOX 271128
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
428 AM PDT Thu Jun 27 2024

.SYNOPSIS...26/806 PM.

Cooling temperatures are expected through Friday as high pressure
weakens over the area and onshore flow strengthens. Night through
morning low clouds and fog will become more widespread through
the end of the week. Warmer weather is expected over the weekend
and into early next week as high pressure returns.

&&

.SHORT TERM (TDY-SAT)...
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27/428 AM.

Low clouds were rather slow to develop this morning, and were
confined to southern portions of the Central Coast. Clouds may
become a bit more widespread on the Central Coast and could spread
into the Santa Ynez Valley by daybreak. Elsewhere, some low clouds
developing to the south and west of L.A. County may affect coastal
sections of L.A. County and possibly Ventura County for a few
hours this morning. Any low clouds should burn off by mid to late
morning.

Good north to south offshore pressure gradients across SBA County
brought low end advisory level winds to southwestern SBA County
last evening, with gusty but below advisory level winds thru the
I-5 Corridor. Those winds have dropped below advisory levels, so
the advisory was allowed to expire.

An upper low in Washington state early this morning will push
across northern Idaho and Montana later today and tonight, with a
broad trough extending southward into the forecast area. There
will be very little change in heights and thicknesses across the
region, and there is just a touch of cooling at 850 mb and 950
mb. Onshore gradients between KLAX and KDAG also change very
little. Expect max temps today to be similar to those on Wed, or
possibly a couple of degrees cooler in most areas.

N-S gradients are forecast to increase very slightly across SBA
County tonight, so expect another round of low-end wind advisory
levels NW winds across the western portions of the south coast of
SBA County and the western Santa Ynez Range. Have issued wind
advisories there for late this afternoon through late tonight.
Gusty winds through the I-5 Corridor should stay below advisory
levels.

The high resolution models suggest more in the way of low clouds
in coastal areas tonight, so expect more widespread low clouds,
affecting most coastal areas (with the exception of the south
coast of SBA County due to northerly flow). Clouds could even push
into the lower valleys. However, confidence in the low cloud
forecast is not particularly great given the dearth of low clouds
this morning.

A weak short wave trough will approach the West Coast on Fri.
Heights will actually fall a bit, as will temps at 850 mb and 950
mb. Should stratus become widespread tonight/Fri morning, clouds
may linger into the afternoon, especially near the coast. Max
temps may be down a couple of degrees in most areas on Fri.

Heights will rise across the region Fri night and Sat as a large
upper high over the southeastern United State expands westward.
There should be area of low clouds and fog in coastal and some
lower valley areas Fri night/Sat morning, but clearing should be
rather quick on Sat. Height rises and warming at 950 mb should
lead to several degrees of warming in most areas Sat, especially
away from the coast. The best warming will likely be in the valley
as the marine inversion lowers, decreasing the marine influence
there. High temps may rise well into the 90s in the warmest
locations in the valleys of L.A. County on Sat.

.LONG TERM (SUN-WED)...26/222 PM.

The peak of the heat will likely be Sunday and Monday. Max temps
will probably exceed 100 degrees in the Antelope Valley and the
interior valleys of SLO County, with highs near 100 degrees in
some of the warmer locations in the valleys of VTU and L.A.
Counties. N-S gradients will increase both Sun night and Mon
night, which could bring some gusty winds to southern SBA County
and the I-5 Corridor, along with a reduction in coastal stratus in
southern SBA County.

Heights will remain quite high across the region Tue and Wed,
although they will lower a bit as the upper high weakens and
shifts eastward. Onshore flow will increase each day. The extended
pattern into next weekend looks like it will be a hot one.
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&&

.AVIATION...
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27/1121Z.

Around 0830Z, the marine layer depth was around 800 feet deep.
The top of the inversion was near 3800 feet with a temperatures
of 24 degrees Celsius.

Low-to-moderate confidence in the current forecast for coastal
terminals. High confidence in the current forecast for valley and
desert terminals. There is a moderate-to-high chance of LIFR to
IFR conditions at coastal terminals through 16Z, otherwise VFR
conditions are expected to persist.

KLAX...There is a 40 percent chance IFR conditions through 16Z.
Any easterly wind component will remain less than 5 knots. Any
return of low clouds as IFR conditions could occur as early as
05Z, or as late as 11Z.

KBUR...VFR conditions are expected through the period. No wind
impacts are expected at this time.
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&&

.MARINE...
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27/421 AM.

High confidence in the current forecast through Saturday, then
moderate confidence thereafter.

At least, Small Craft Advisory (SCA) winds and seas will continue
for the waters southwest through northwest Channel Islands and
nearshore along the Central Coast through early Saturday. For the
waters northwest of the Channel Islands and beyond 10 NM offshore,
there is a 70-90 percent of Gales for today and tonight. Gales
should end by Friday morning. There is a moderate-to-high chance
of SCA level winds on Saturday afternoon and night, lowering some
into Sunday afternoon and night.

Inside the southern California bight, there is a 40-50 percent
chance of SCA level northwest winds across the western Santa
Barbara Channel this evening. Otherwise, winds will remain below
SCA levels for the remainder of the area.
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&&

.LOX WATCHES/WARNINGS/ADVISORIES...
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CA...Wind Advisory in effect from 4 PM this afternoon to 3 AM PDT
      Friday for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Friday for zone
      645. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Friday for zones
      670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Saturday for
      zone 676. (See LAXMWWLOX).
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&&

$$

PUBLIC...DB/DB/jld
AVIATION...Hall
MARINE...Hall
SYNOPSIS...jld/Smith

weather.gov/losangeles

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