099
FXUS66 KLOX 291740
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1040 AM PDT Mon Apr 29 2024

.SYNOPSIS...29/835 AM.

Mostly clear skies and warmer temperatures will prevail across
the region through this week, although some night through morning
coastal low clouds and fog can be expected at times. Gusty
northwest to north winds will prevail over the mountains and
deserts at least through Tuesday.

&&

.SHORT TERM (TDY-WED)...29/834 AM.

***UPDATE***

A weak eddy brought low clouds and fog into parts of the L.A.
County coast early this morning. Low clouds and fog also formed
over interior areas of northern SLO County as well as the eastern
Santa Ynez Vly. These low clouds are forecast to dissipate by late
this morning. Otherwise, sunny skies covered the forecast area
this morning which will continue thru this afternoon.

Northerly pressure gradients increased early this morning helping
to keep gusty NW to N winds over portions of the SW SBA County
mtns and coast, VTU County mtns, L.A. County mtns along the I-5
Corridor, and the western Antelope Vly foothills into the Antelope
Vly. Advisory level wind gusts to 40 to 50 mph at times can be
expected in these areas today, especially this afternoon, and
Wind Advisories will continue. Breezy to gusty W-NW winds will
also affect much of the coast and adjacent vlys thru this
afternoon, strongest on the Central Coast where winds could
approach Advisory levels at times.

A flat upper level pattern with H5 heights around 576 dam will
persist over the area today, helping to keep temps near normal to
a few degrees above normal. Highs this afternoon for the inland
coast, vlys and lower mtns should reach the 70s to low 80s, with
the warmest temps in the western San Fernando Vly.

***From Previous Discussion***

Not much going on for the next three days. Winds will be the only
concern. The state will be under NW slightly cyclonic flow through
the period with hgts near 576 dam today and Tue falling to 574 dam
on Wed. There will be continuous offshore flow from the north
through the three day period peaking near 5 mb early Tuesday
morning. There will be weak onshore flow to the east both today
and Wednesday but it will be weakly onshore on Tuesday.

Skies will be mostly clear through the period. The only possible
exceptions will be some night through morning low clouds over two
small areas. The first area will be the western portion of SBA
county where west winds will create back building low clouds in
the Santa Ynez valley which will spread back into the coastal
plain. The second area will be the LGB-LAX area where a weak eddy
may bring some low clouds up from the south in the early mornings.

As mentioned above winds will be the biggest issue over the next
72 hours. The offshore N to S gradients will combine with the
northerly upper level flow to produce periods of advisory level
winds from now until Tuesday afternoon and  beyond into
Wednesday. The winds will peak tonight as the offshore sfc
gradients reach their peak. Due to the diurnal cycle of the
pressure gradients there will be lulls in the winds esp in the
afternoons and early evenings. Please see the product LAXNPWLOX
for all of the wind advisory informations.

Most areas will warm today and Tuesday. Max temps will cool some
on Wednesday as the offshore flow relaxes. Most max temps across
the csts/vlys will be in the 70s with a smattering of lower 80s in
the warmest vly locations. These max temps will be a few degrees
either side of normal.

.LONG TERM (THU-SUN)...29/319 AM.

The EC and GFS both ensembles and deterministic runs are in
decent agreement Thu and Fri. At the upper levels there will be
increasing troffiness which would normally cool things, but
another round of offshore flow from both the north and east will
prevent that and actually warming to the coasts and vlys. On
Friday a reversal to onshore flow will bring increased morning low
clouds and cooling to the csts and vlys.

Mdl agreement wanes sharply for the weekend day 6 and 7 forecast.
The GFS and esp its deterministic run is steadfast in its resolve
to bring a late season storm to the area. The EC and most of its
ensembles just run a broad trof over the area. The GFS ensembles
are pretty varied and do not strongly support the stormy scenario.
At this time the weekend forecast is biased towards the EC
solutions and is dry. There will be a cooling trend each day with
the GFS coming in much cooler than the EC. Again the cooling trend
has been slanted in the EC`s direction. Still need to keep an eye
on the evolution of the GFS`s fcst and if the EC shows any trend
towards a deeper wetter soln as well.

&&

.AVIATION...29/1739Z.

At 1719Z at KLAX, the marine layer was 500 ft deep with an
inversion top at 2300 ft with a maximum temperature of 17 C.

High confidence in TAFs, except for KLAX and KLGB (30% chc of no
cigs), KSMO (40% chance of IFR cigs from 12Z-16Z Tue), and KOXR
(15% chance of IFR cigs after 14Z Tue).

KLAX...Moderate confidence in TAF. There is a 30% chance of no
cigs developing tonight. No significant easterly wind component is
expected.

KBUR...Moderate to high confidence in TAF, some uncertainty in
wind direction after 04Z Tue.

&&

.MARINE...29/947 AM.

For the outer waters, the extended period of gale force winds is
expected to continue thru at least Tue night. Swell will continue
to be short- period and choppy, with the potential for dangerous
breaking waves at west- facing harbors. SCA conds are expected for
the outer waters, Wed thru Fri, with a 30% chance of gales
persisting into Wed night.

In the inner waters N of Pt. Sal, SCA level winds are likely thru
Tue night, with a 25% chance of gale force winds this
afternoon/evening. Then, there is a 50% chance of SCA conds
during the afternoon/evening hours Wed thru Fri. Seas are expected
to be at/near SCA level through Wed.

In the SBA Channel, SCA level W-NW winds are expected, particular
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, most of the time 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
today thru Tue.

&&

.BEACHES...29/947 AM.

Persistent strong winds and outer water swell heights of 10-15
feet with a 10 second period will lead to high surf (8-12 feet)
along the Central Coast this afternoon through Tuesday night.
Surf will be highest across northwest-facing beaches. There is a
40% chance of high surf advisory criteria lingering through
Wednesday evening. NO coastal flooding is expected.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect from 2 PM this afternoon to 2 AM
      PDT Wednesday for zones 340-346. (See LAXCFWLOX).
     Wind Advisory now in effect until 3 PM PDT Tuesday for zones
      349-351. (See LAXNPWLOX).
     Wind Advisory in effect until 3 PM PDT Tuesday for zones
      352-353-376-377. (See LAXNPWLOX).
     Wind Advisory remains in effect until 3 PM PDT Tuesday for
      zones 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 from 3 PM this afternoon to 3
      AM PDT Tuesday for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Wednesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke/Sirard
AVIATION...Schoenfeld
MARINE...Lund/Schoenfeld
BEACHES...Lund/Schoenfeld
SYNOPSIS...Sirard

weather.gov/losangeles

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