736
FXUS66 KLOX 271540
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
840 AM 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...27/1317Z.

At 1211Z at KLAX, the marine layer was 1200 ft deep. The top of
the inversion was at 4200 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 could be off by +/- 4 hours. KBUR
and KVNY have a 20% chance of remaining VFR through 11Z Tue, and a
20% chance of IFR- Low MVFR CIGs after 11Z Tue. 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 could
be off by +/- 2 hours. There is a 20% chance of BKN004 conds
after 06Z Tues. 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 30% chance of conds remaining
VFR through 11Z Tue, and a 20% chance of BKN008-BKN012 after 11Z.

&&

.MARINE...27/254 AM.

Moderate to high confidence in forecast.

Across the outer waters, lower confidence in forecast this
morning as winds and seas are still near Small Craft Advisory
(SCA) levels. While winds are expected to drop off this morning,
seas are still choppy with short periods, so decided to extend the
advisory. Winds are likely to restrengthen to SCA levels this
afternoon and continue through Thursday. There is a 20-30% chance
(highest for the northern waters) of Gale Force winds Tuesday
afternoon and night. Then for all the outer waters there is a
50-60% chance of Gales Wednesday afternoon through night. On
Tuesday, seas will build to SCA levels and remain steep and choppy
through at least Thursday night.

Across the nearshore waters along the Central Coast, there is a
20-30% chance of SCA winds this afternoon and evening. Tuesday
afternoon through Wednesday night, SCA level winds and seas are
likely (60-70%), 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 60-70% 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,
winds are expected to remain below SCA levels through at least
Thursday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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