143
FXUS66 KLOX 280013
AFDLOX

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

.SYNOPSIS...27/148 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 (TDY-THU)...27/144 PM.

The low clouds from this morning have cleared back to the coast
early this afternoon, with low clouds lingering at some of the
beaches. Otherwise, mostly sunny skies covered the forecast area
with little change expected for the rest of the day.

Temps this afternoon are forecast to turn a few degrees warmer
than yesterday, but still remain several degrees below seasonal
norms for most areas. However, for the interior vlys and deserts,
temps should turn out to be near normal to a couple of degrees
warmer than normal. Highs for the inland coast, vlys and lower
mtns should reach the 70s to near 80, except lower 80s in the
SLO/SBA County interior vlys, and mid 80s to around 90 for the
Antelope Vly.

Strong onshore pressure gradients will help to bring breezy to
gusty SW-NW winds to much of the area this afternoon. The
strongest winds, but still below Advisory levels, are expected for
the Antelope Vly into the foothills.

A broad SW flow aloft with H5 heights up to 581-582 dam will
prevail over southwest CA this afternoon. Little change can be
expected thru tonight then flat upper ridging should move in with
H5 heights expected to be around 583-584 dam by Tue afternoon. The
upper level flow should turn more W to NW Tue night thru Thu,
with H5 heights increasing further to near 585 dam by Wed
afternoon.

The May gray marine layer pattern will continue for the most part
thru Thu across SW CA. The marine inversion is forecast to lower
to around 1200-1500 ft or so tonight, to near 1000-1400 ft Tue
night, and to about 700-1200 ft Wed night. Low clouds and some fog
should affect much of the coast and adjacent vlys tonight into
Tue morning. An increasingly strong northerly pressure gradient
should help to limit low clouds along the Central Coast Tue night
into Wed morning and Wed night into Thu morning. S of Point
Conception, night and morning low clouds and fog should affect the
coast and some adjacent vlys. The low clouds should clear off the
coast for the most part by early afternoon each day, with Santa
Catalina Island probably having some low clouds linger thru much
of the day. Otherwise and elsewhere, mostly clear nights and
mostly sunny days should prevail.

The increasing northerly pressure gradients will bring gusty
sundowner winds at below Advisory levels to western portions of
the S SBA County coast and mtns this evening, then increase to
near Advisory levels for Tue evening and possibly Wed evening.
Gusty NW winds will also affect the L.A. County mtns mainly near
the I-5 corridor and the Antelope Vly including the foothills,
strongest and possibly to Advisory levels from Tue evening thru
Wed night. There will also be strong onshore gradients to the E
with breezy to gusty SW-NW winds for many areas during the period,
strongest afternoon and early evening hours.

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 or approaching
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, there is a
40-60% chance of SCA winds this afternoon into 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% chance of SCA
level winds across the western portion of the Santa Barbara Channel
this afternoon and evening increasing to 30-40% chance 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 Wednesay
afternoon. Wednesay afternoon/evening 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...Sirard
AVIATION...Gomberg/Schoenfeld
MARINE...Lund/Schoenfeld
SYNOPSIS...Sirard

weather.gov/losangeles

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