154
FXUS66 KLOX 290238
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
738 PM PDT Sun Apr 28 2024

.SYNOPSIS...28/737 PM.

Mostly clear skies and warmer temperatures will prevail across
the region through this week, with just some coastal low clouds
and fog possible at times night and morning hours early in the
week and again late in the week. Gusty west to north winds will
prevail over the mountains and deserts at least through Tuesday.

&&

.SHORT TERM (SUN-WED)...28/735 PM.

Satellite imagery showing mostly clear skies across the forecast
area this evening, except patches of low clouds forming across
the Central Coast. At upper levels, a northwest flow pattern will
persist through Tuesday. This in combination with northerly
offshore pressure gradients near the surface will continue
to bring gusty northwest to north winds across portions of the
forecast area through at least Tuesday. The wind advisory was
extended until 3 pm Tuesday for the mountains, Antelope Valley
and adjacent foothills. For southwest Santa Barbara county, the
wind advisory remains in effect through 3 pm Monday, but could be
extended. These areas should generally see wind gusts of 45 to
50 mph, except locally up to 55 mph across the I-5 corridor and
western Antelope Valley foothills. As of 7 pm, already seeing
some wind gusts of 48 mph at Gaviota and 46 mph at Refugio.

The persistent strong northwest flow pattern across the outer
coastal waters will continue to generate a weak eddy circulation
the next few nights. As a result, there is increasing potential
(60-70% chance) for low clouds to develop during the late night
and morning hours across the LA county coast, with a small chance
(20-30%) of reaching the Ventura county coast. Latest ACARS data
still showing a weak inversion developing across the LA Basin, so
may be difficult for a solid stratus field to develop overnight.
Latest HREF probabilistic guidance also trending towards low
clouds returning to coastal LA county overnight and again Monday
night.

Weak upper level ridging moved over Southern California today,
bringing a warming and drying trend away from the coast. Little
change in heights is expected Monday into Tuesday, but boundary
layer temperatures continue to edge upward. As a result, could see
a few more degrees of warming across interior next couple of days,
with warmest valley and desert areas expected to climb into the
lower 80s.

.LONG TERM (THU-SUN)...28/157 PM.

The EC and GFS mean ensembles and deterministic are in generally
good agreement Thu thru Sat with broad but generally weak upper
level troffiness over the forecast area. By Sun, the deterministic
models diverge quite a bit with the GFS forecasting a significant
for early May storm system affecting the region with rain and
high elevation mtn snow, while the EC has dry weather with rising
H5 heights over the region. The GFS mean ensembles bring a 10%-20%
chance of measurable rain to the area Sun, as only 4 out of 30
ensemble members show rain moving into the area at that time. For
now we will go with a dry forecast for day 7.

High pressure is fcst to move into NV on Thu morning and will set
up offshore flow from both the N and E. A low end Santa Ana wind
event will develop and keep any low clouds well offshore. Mostly
clear skies are then expected to continue across the forecast area
Thu night thru Sat, except for some night and morning low clouds
and fog along the Central Coast Fri night into Sat morning.
Increasing clouds are possible by Sun, and there may be some low
clouds and fog along the coast into the adjacent vlys Sat night
into Sun morning.

With the offshore flow Thu and even some into Fri, temps are
expected to be warmest for the week, with inland coast, vlys and
lower mtns expected to top out in the mid 70s to mid 80s. A
smattering of upper 80s is possible on Thu for the warmest vlys.
It will turn cooler next weekend, with highs 2-6 deg below normal
for many areas by Sun.

&&

.AVIATION...28/2321Z.

At 2215Z, the marine inversion at KLAX was based at 900 feet.
The top of the inversion was 2300 feet with a temperature
of 15 degrees Celsius.

Overall, moderate to high confidence in 00Z TAF package. For KLAX
and KLGB, only moderate confidence as there is a 50% chance that
CIG/VSBY restrictions do not develop overnight. For KSMX, there is
a 30% chance of IFR/LIFR conditions 09Z-17z.

KLAX...Moderate confidence in 00Z TAF. There is a 50% chance that
CIG/VSBY restrictions do not develop overnight. No significant
easterly wind component is expected.

KBUR...High confidence in 00Z TAF.

&&

.MARINE...28/725 PM.

A very long period of gale force winds is expected to continue
thru at least Tue night for the outer waters. SCA conds are
expected Wed thru Thu, with a 30% chance of gales persisting into
Wed evening.

In the inner waters N of Pt. Sal, SCA level winds are likely thru
Tue night, especially in the afternoon/eve hours. There is a 50%
chance of SCA conds during the afternoon/eve hours Wed/Thu. Seas
are expected to be near SCA levels during the periods of weaker
winds. There is a 25% chance of gale force winds during the
afternoon/eve hours Mon into Tue.

In the SBA Channel, SCA level W-NW winds are expected across
western portions during the afternoon thru late night hours
thru Wed. Winds will likely remain below SCA levels for eastern
portions of the channel through the period.

In the southern inner waters, there is a 20% chance of SCA level
W to NW winds across northwestern portions, mainly from Anacapa
Island to Malibu during the late afternoon thru late evening hours
thru Tue.

Widespread strong to gale force winds will keep dangerous sea
conditions across much of the coastal waters (particularly the
outer waters) thru the middle of the week, with short-period,
steep, and choppy waves. There may be dangerous breaking waves
near west-facing harbors. Mariners should plan accordingly.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 3 PM PDT Monday for
      zones 349-351. (See LAXNPWLOX).
     Wind Advisory now in effect until 3 PM PDT Tuesday for zones
      377-378-381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Monday for zone
      650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Wednesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Sirard
AVIATION...RAT
MARINE...Gomberg/RM
SYNOPSIS...Sirard

weather.gov/losangeles

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