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000
FXUS66 KLOX 170453
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
953 PM PDT Tue Apr 16 2024

.SYNOPSIS...16/952 PM.

Dry and warmer conditions will prevail across the region this
week and through the weekend. Night through morning low clouds
and fog will affect portions of the coast and valleys through the
period.

&&

.SHORT TERM (TUE-FRI)...16/951 PM.

***UPDATE***

Clear skies and rising hgts combined today to bring 6 to 12
degrees of warming to SLO and SBA counties and 10 to 15 degrees
across VTA and LA counties where the offshore flow was the
greatest.

The latest high rez ensemble forecasts show decent offshore flow
developing across SLO county and this should greatly reduce the
chance of low clouds there. There is a slightly greater than 50
percent chc of low clouds in the Long Beach LAX area towards dawn
and there is a forecast of low clouds but would not be surprised
if they do not form. The best chc of low clouds tonight will be
across western SBA county.

Current fcst for tomorrow looks good with further warming across
the mtns and inland areas. The coasts and vlys, however will cool
some as the offshore flow weakens.

***From Previous Discussion***

Synoptically, the area is under an EastPac ridge pushing 580 dam
(ish) heights over the area while most of the CONUS is in a deep
trough around a low near Minnesota. In the next 24 hours the
pattern over us will become zonal and then develop into a slight
trough. By Saturday the ridge should return, although weaker than
it is today. By midweek a trough begins to drop down the Pacific
coast associated with a Gulf of Alaska low that may actually bring
a little more rain to the area mid week.

Max temps rose 6 to 12 to locally 15 degrees today as the result
of a combination of April sunshine, offshore flow, and rising
hgts. The offshore flow will relax tonight and the low cloud
pattern will likely reform across the Central Coast and the
Salinas River vly. Low clouds are also probably going to be over
the Oxnard plain.

Skies will be sunny on Wednesday save for the low clouds which
will not last past mid morning. The offshore will be weaker and
this will allow for an earlier seabreeze which will bring 2 to 4
degrees of cooling to the csts/vlys. Hgts will rise another 2 or 3
dam as the ridge peaks and this will lead to another 3 to 6
degrees of warming across the mtns and far interior.

On Thursday the ridge will move to the east and a weak trof cover
the area, bringing enough mid and high level clouds to make the
day a mostly cloudy one. The lifting heights along with a sharp
increase in onshore flow to the east will bring low clouds to the
coasts and most of the vlys. The afternoon onshore push to the
east is fcst to be near 7 mb and its likely that the low clouds
will not clear many coastal areas. Look for 4 to 8 degrees of
cooling across the board - this will bring the csts and vlys max
temps down below normals. The mtns and the far interior, however,
will remain likely above normal. Max temps across the csts and
vlys will end up in the mid 60s to the mid 70s.

Weak troffing will persist over the area on Friday. There will be
another round of morning low clouds across the coasts and most of
the vlys. There will be weaker onshore flow in the afternoon and
this will allow for better clearing. The mid and high clouds will
also be past the area so there will be much more sunshine. The
lower hgts will serve to cool the area but the sunnier skies and
weaker onshore flow will counteract this cooling. The end result
is that there will be hodge-podge of warming and cooling across
the forecast area.

.LONG TERM (SAT-TUE)...16/224 PM.

Model solutions are in good agreement in the long term.  There
should be a warming trend Sat and Sun as the ridge reestablishes
itself. The onshore flow will relax even becoming offshore from
the north on Sunday. The amount of morning low clouds will subside
and Sunday may well end up cloud free. Max temps will rise 2 to 4
degrees each day. By Sunday cst/vly max temps will end up 2 to 4
degrees above normal while the mtns and far interior will be 5 to
10 degree warmer than normal. Almost all of the vlys will see
temps in the 80s.

The marine layer is expected to deepen by Mon as the ridge weakens,
and onshore flow increases, cooling temps to several degrees
below normal for the coast and vlys while the interior will remain
above normal. Most max temps will come in within 2 degrees of
Thursday`s values.

Some ensemble solutions have a 20% chance of 0.1" of rain on
Tuesday as the trough deepens, but there isn`t enough of a signal
for the NBM to catch on to it yet. There is a better, but still
small, chance for rain (only about 0.1") later in the week as the
10-day outlooks indicate a trough will drop down the coast from a
Gulf of Alaska low.

&&

.AVIATION...17/0153Z.

At 00Z, there was a weak marine inversion at KLAX at about 800 ft.
The top of the inversion was at 1700 ft with a temp of 21 deg C.

High confidence in the 00Z TAFs for deserts and valleys. Moderate
confidence in coastal TAFs as cigs are possible in the early
morning hours. The timing of any low clouds may be off +/- an
hour or so.

KLAX...Moderate confidence in the 00Z TAF. There is a 40%-50%
chance of MVFR cigs about 11Z-16Z Wed. Otherwise VFR conds will
prevail. Any east wind component should remain less than 6 knots.

KBUR...High confidence in the 00Z TAF with VFR conds thru the pd.

&&

.MARINE...16/752 PM.

Generally high confidence in the current forecast.

In the outer waters, Small Craft Advisory (SCA) level winds and
steep seas will continue thru late tonight, then SCA conds are not
expected through Friday. There is then a 40%-50% chance of SCA
conds Friday night through Sunday.

In the inner Waters N of Pt. Sal, SCA conds are not expected
through Sunday, except there is a 20%-30% chance of SCA wind gusts
at times especially during the evening hours Friday through
Sunday.

In the Inner Waters S of Pt. Conception, SCA conds are not
expected through Sunday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke/jld
AVIATION...Phillips
MARINE...Sirard/Smith
SYNOPSIS...Sirard

weather.gov/losangeles

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