845
FXUS66 KLOX 280326
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
826 PM PDT Mon May 27 2024

.SYNOPSIS...27/823 PM.

The marine layer pattern will continue through next Monday.
Varying amounts of night and morning low clouds and fog will
affect the coast and valleys, otherwise mostly clear skies will
prevail. Temperatures will be a few degrees below normal through
Tuesday then warm to near normal to a few degrees above normal
through the weekend. Breezy northwest to onshore winds will
continue to be strongest each afternoon and evening for far
interior areas and southwest Santa Barbara County.

&&

.SHORT TERM (MON-THU)...27/822 PM.

At upper levels, a weak upper level trough of low pressure
will prevail across northern and central California, but heights
gradually rise across our region the next couple of days. Near the
surface, strong onshore flow will continue with LAX-Daggett
pressure gradient expected to peak in the +7 to + 8 mb range each
afternoon through Thursday. Current satellite imagery showing
low clouds filling in across portions of the Central Coast and
LA county coast. The marine layer depth is expected to gradually
shrink the next couple of nights due to the rising heights, with
low clouds expected to fill in across most coastal and coastal
valley locations. The low clouds should clear to or off the coast
for the most part each afternoon.

Gusty onshore winds are somewhat weaker and less widespread
across the Antelope Valley this evening, however still seeing
some local wind gusts to around 40 mph near Lake Palmdale.
Many interior areas saw warming today, with another degree or
two of warming expected on Tuesday with little change into
Wednesday. High temperatures in the Antelope Valley will be
approaching 90 degrees.

Sundowner winds expected to strengthen on Tuesday night and
more so on Wednesday night, likely reaching advisory levels
across western portions, with gusts in the 40-50 mph range.
W-NW winds are also expected to ramp up across the I-5 corridor
and Antelope Valley Tuesday night through Wednesday, potentially
reaching advisory levels.

*** from previous discussion ***

Temps should remain several degrees below normal Tue, except
increasing to a few degrees above normal for the interior areas
including some of the mtns and into the Antelope Vly. By Wed, temps
will turn a little bit warmer with highs near normal to a few
degrees above normal for many areas. On Thu, most areas should have
even warmer temps to near normal to several degrees above normal.
Highs for much of the inland coast, vlys and lower mtns should be in
the 70s to lower 80s Tue and in the mid 70s to mid 80s Wed and Thu,
except warming into the 80s to around 90 for the SLO/SBA County
interior vlys. The warmest areas should be in the Antelope Vly,
with highs in the upper 80s to around 90 thru Wed then increasing
to the low to mid 90s for Thu.

.LONG TERM (FRI-MON)...27/147 PM.

Not a whole lot of change can be expected in the extended period.
It looks like a flat upper level ridge with H5 heights around
583-584 dam will affect the region on Fri, then weak upper level
troffiness should persist Sat thru Mon (according to the mean
ensembles) with H5 heights around 582-584 dam.

Good onshore pressure gradients to the N and E will help to keep
the marine layer pattern over the forecast area Fri thru Mon.
Widespread night and morning low clouds and fog are expected for
the coast and vlys, moving farthest inland Sun and Mon, including
into the northern SLO County interior vlys, as the marine
inversion deepens. Otherwise, mostly clear skies can be expected
thru the period, except for lingering low clouds each day for
Catalina Island.

Just minor day-to-day changes in temps are forecast, with
readings ranging from a few degrees below normal to a few degrees
above normal depending on location, but the warmest temps should
be for the interior vlys, lwr mtns and deserts. Afternoon highs
for the inland coast and vlys should be in the 70s to around 80
each day, except into the 80s to near 90 for the interior vlys as
well as lower mtns, and generally into the lower 90s in the
Antelope Vly.

&&

.AVIATION...28/0011Z.

At 0020Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was at 3800 feet with a temperature of 18 C.

High confidence in desert TAFs and low confidence in
coastal/valley TAFs. Low-moderate confidence for coastal/valley
sites due to uncertainties in the behavior of the marine layer
stratus. Timing of flight cat changes tonight could be off by +/-
4 hours. KBUR and KVNY have a 20% chance of remaining VFR through
the period. There is a 50-70% chance of KSMX, KSBP, KSBA, KOXR,
and KCMA dropping to LIFR conds after 07Z Tues.

KLAX...Moderate confidence in TAF. Cigs now expected to persist
through Tuesday morning. Timing of flight cat changes tonight
could be off by +/- 3 hours. No significant easterly wind
component is expected.

KBUR...Low confidence in TAF. Timing of flight cat changes could
be off by +/- 3 hours. There is a 20% chance of conds remaining
VFR through the period

&&

.MARINE...27/110 PM.

Moderate to high confidence in forecast.

Across the outer waters, wind and seas are at Small Craft
Advisory (SCA) levels. SCA conditions are expected to persist much
of the time through Thursday night, except for the outer waters
south of the Channel Islands - where conditions are likely to drop
below SCA level late tonight and tomorrow morning. Winds will be
strongest Tuesday and Wednesay afternoons/nights. There is a
20-30% chance of gales Tuesday and a 50-60% chance of gales
Wednesday, thus a Gale Watch has been issued for all the outer
waters Wednesday afternoon and night. Choppy steep seas will peak
Wednesday morning into Thursday morning at around 10 to 13 feet,
and SCA seas may linger as late as Thursday night.

Across the nearshore waters along the Central Coast, SCA winds
have ended this evening. Tuesday afternoon through Wednesday
night, SCA level winds and seas are likely (60-80%), with a 15-25%
chance of Gale Force winds Wednesday afternoon/evening. SCA seas
may linger as late as Thursday night.

Across the southern inner waters, there is a 30-40% chance of SCA
winds Tuesday afternoon and evening. On Wednesday, there is a
60-80% chance of SCA winds across the western portion of the
Channel, with a 20-30% chance of Gale Force winds. South of the
Channel Islands, conditions are expected to remain below SCA level
until Wednesday afternoon. At that time there is a 30% chance of
SCA wind and/or seas.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 9 PM PDT this evening
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT Wednesday for
      zones 670-673. (See LAXMWWLOX).
     Gale Watch in effect from Wednesday afternoon through late
      Wednesday night for zones 670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Sirard
AVIATION...Gomberg/Schoenfeld
MARINE...Lund/Schoenfeld/Smith
SYNOPSIS...Sirard

weather.gov/losangeles

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