322
FXUS66 KLOX 271901
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1201 PM PDT Mon May 27 2024

.SYNOPSIS...27/839 AM.

The marine layer pattern will continue through Sunday. 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-WED)...27/834 AM.

***UPDATE***

The marine inversion early this morning ranged from around 1900
ft deep at VBG to around 2100 ft deep at LAX. Low clouds covered
much of the coast and vlys of L.A. County (except the Santa
Clarita Vly), the VTU County coast, the SBA County S coast, the
Central Coast and Santa Ynez Vly. The low clouds are expected to
clear back to or off the coast by early this afternoon, with
Catalina Island probably remaining mostly cloudy thru the day.
Otherwise and elsewhere, mostly sunny skies will prevail thru this
afternoon.

Temps today 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. Afternoon 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, especially this afternoon.
The strongest winds, but still below Advisory levels, are expected
in the Antelope Vly into the foothills.

***From Previous Discussion***

Forecast thoughts remain relatively unchanged. Building 500 mb
heights will lead to a warm up through Tuesday with unabated
onshore flow and marine layer presence limiting the warm up near
the coast. Forecast confidence of low cloud coverage remains low
today, but the low cloud pattern should become more persistent and
therefore easier to forecast by Tuesday thanks to the warming
trends above the marine layer, establishing a stronger inversion.
Daytime highs only in the 60s will prevail nearest the coast,
inland coastal areas and valleys will peak in the 70s to low 80s,
with 80s to near 90 for the far interior.

Breezy northwest to onshore winds will continue through this
period. An inside slider trough will likely enhance winds across
the region by Wednesday with a 30-50 percent chance of reaching
advisory levels at times Tuesday afternoon through Wednesday night
across the Antelope Valley, I-5 corridor through the mountains,
and southwest Santa Barbara County. Offshore trends to the south
will likely support morning clearing of low clouds and fog. Some
south facing coasts, most notably the Santa Barbara South Coast,
will likely be mostly sunny by Wednesday. The uptick of northwest
winds may support a stronger Catalina Eddy Wednesday or Thursday,
which could send low clouds and fog as far inland as the lower
mountain slopes. Should this occur, daytime highs would be closer
to 75 as opposed to the currently advertised 80 for coastal
valleys of Los Angeles and Ventura Counties.

.LONG TERM (THU-SUN)...27/322 AM.

High forecast confidence for Thursday through the weekend mainly
subtle day-to-day changes with typical late May weather on tap.
Night to morning lows clouds and fog will continue for coasts and
many coastal valleys. Low clouds and fog should burn off mid to
late morning for most areas especially Friday into next weekend.
Daytime highs will likely be mid 60s to mid 70s for most coastal
areas, mid 70s to mid 80s for coastal valleys, and 80s to near 90
for the far interior. Breezy northwest to onshore flow will
continue unabated, peaking each afternoon to evening, with a 10-20
percent chance of reaching advisory levels for the Antelope Valley
and southwest Santa Barbara County.

&&

.AVIATION...27/1833Z.

At 1755Z at KLAX, the marine layer was 2100 ft deep. The top of
the inversion was at 4800 feet with a temperature of 16 C.

High confidence in desert TAFs and low confidence in
coastal/valley TAFs. Lower 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 30% chance of KSMX, KSBP, KOXR, and KCMA
dropping to LIFR conds after 08Z Tues.

KLAX...Low confidence in TAF. 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...27/1159 AM.

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 AM PDT Tuesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Munroe/Sirard
AVIATION...Schoenfeld
MARINE...Lund/Schoenfeld
SYNOPSIS...Sirard

weather.gov/losangeles

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