887
FXUS66 KLOX 290610
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1110 PM PDT Tue May 28 2024

.SYNOPSIS...28/705 PM.

Increasing northerly flow this week is expected to cause earlier
and more complete clearing of the marine layer, leading to
slightly warmer temperatures and more afternoon sunshine. Breezy
northerly winds will develop across southern Santa Barbara County
and some interior areas each afternoon and evening.

&&

.SHORT TERM (TDY-THU)...28/728 PM.

***UPDATE***

Increasing northerly flow is expected across portions of Southwest
California this week, mainly tonight through Wednesday night, but
potentially decreasing through Thursday. A trough passing through
the Pacific Northwest will extend southward, with weak troughing
into southern California tonight into Wednesday. As this occurs,
northern flow will increase over SW Santa Barbara County and
through the Interstate 5 Corridor, with gusty westerly winds
extending into the Antelope Valley. Portions of the Central Coast
will likely see gusty winds as well, during the afternoon to
evening hours. Southwest Santa Barbara County is most likely to
see Advisory level gusts later this evening, but especially
Wednesday evening. Another area of concern is the Ventura and LA
Mountains around the Grapevine, where gusts to 40 mph with
isolated gusts to 50 mph are likely to occur late this evening and
overnight.

With the gusty northerly flow, there is a good chance of earlier
clearing for the coastal valleys, and even for some coastal areas,
although this is somewhat lower confidence.

***From Previous Discussion***

Another tangential impact will likely be decreasing marine layer
stratus along the Central Coast through Santa Barbara and a
shallower and earlier clearing marine layer elsewhere. There will
still be a weak eddy circulation over the southern coastal waters
that will maintain a solid cloud cover but it will likely clear
earlier in the day and not return until after midnight in most
areas. Some warming is expected as well, however, a cool sea
breeze is still expected each afternoon near the coast which will
cap any warming there to just a couple degrees at most over the
next few days. Most valleys should top out in the low to mid 80s

.LONG TERM (FRI-MON)...28/221 PM.

Troughing will return later in the week and especially over the
weekend which will increase onshore flow to the east and weaken
the northerly flow over the outer waters. This will lead to a
deepening and longer lasting marine layer through the weekend as
well as cooling temperatures.

Many ensemble solutions are indicating building high pressure
early next week, but mainly north and east of southwest
California. Most of the NAEFS gradients are still favoring a
rather robust onshore flow pattern locally that will keep our
natural air conditioning going for most areas west and south of
the mountains. Could see some near 90 degrees across our warmest
valley areas, but most valleys will top out in the mid 80s and
coastal areas in the 60s and 70s.

&&

.AVIATION...29/0610Z.

At 05Z at KLAX, the marine layer was 1200 ft deep. The top of the
inversion was at 4100 feet with a temperature of 18 C.

High confidence in desert TAFs, with clear skies and gusty winds
again Wed.

Areas of low clouds will affect coastal areas with the possible
exception of southwestern SBA County and much of the SLO County
coast. Low clouds will push into the Santa Ynez and San Gabriel
Valleys by midnight, and the San Fernando Valley and the valleys
of VTU Counties later tonight. Conditions will be mostly IFR to
LIFR, except locally VLIFR in the valleys/foothills. Cigs should
rise a bit in coastal areas of L.A. County tonight, so conds may
become MVFR. Skies should clear by mid morning in the valleys and
by noon across most of the coastal plain. However, cigs may
linger at the beaches of L.A./VTU Counties thru the day. Expect
clouds to return to coastal areas Wed evening.

KLAX...Moderate confidence in TAF. There is a 20% chance that
cigs will remain IFR thru 15Z. There is 20% chance that cigs will
not clear at all Wed. There is a 20% chance of an east wind
component of 7 to 9 kt from 10Z-16Z Wed.

KBUR...Moderate confidence in TAF. There is a 20% chance that
cigs will arrive as early as 09Z or as late s 13Z. There is a 20%
chance that cigs will be in the LIFR category.

&&

.MARINE...28/930 PM.

Moderate confidence in forecast.

In the outer waters, winds and seas are at Small Craft Advisory
(SCA) levels. Winds are still expected to increase to low-end
gales throughout the outer waters, with the strongest winds in
western portions of these zones. Gales are expected to continue
thru late Wed night, though they may drop below gale force at
times, particularly during the morning. Overall confidence in
gales is 70-80% in northern zones, and 50-60% in the southern
zone. If wind do not reach gale force, the will be strong SCA
levels thru Wed night. SCA level winds will likely continue
Thu/Thu night, and while winds should drop off, seas may remain
close to SCA levels Fri thru Sat.

In the inner waters N of Pt. Sal, SCA winds are likely Wed
afternoon/eve. SCA level seas are likely Wed night thu Thu night,
and there is a 40-50% chance of SCA level winds Thu afternoon/eve.
SCA conds are not expected Fri thru Sat.

In the southern inner waters S of Pt. Sal, SCA winds were limited
to far western portions this afternoon/eve, and will likely
struggle to reach the middle of the Santa Barbara Channel Wed
afternoon/night. There is 20-30% chance of gales in western
portions of the SBA Channel late Wed afternoon/Wed
night. Otherwise, SCA conds are not expected.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Thursday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Smith
AVIATION...DB
MARINE...Phillips/Schoenfeld
SYNOPSIS...MW/Smith

weather.gov/losangeles

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