Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 282321

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
421 PM PDT Sun May 28 2023

.SYNOPSIS...28/1236 PM.

A strong onshore flow pattern will keep a persistent and deep
marine layer in place through the week. Night through morning low
clouds and fog with limited afternoon clearing will continue as
well. Local drizzle is possible each morning across coastal and
valley areas. Temperatures will be cooler than average for most of
the week.


.SHORT TERM (TDY-WED)...28/1240 PM.

A very slow clearing day so far today. Satellite imagery shows
some thinning of the stratus over the coastal waters and even a
little over Santa Barbara but at this point with the clouds still
pushing farther up the coastal slopes it seems unlikely there will
be any significant clearing, even for the Central Coast which
has fared better in that regard over the last few days.

There is some additional cumulus developing in the mountains
today. Forecast soundings have been showing some increased
instability today. Likely not enough for any storms this
afternoon, though it`s not a zero chance either.

With an upper low moving down the coast today through Wednesday
the outlook through mid week isn`t good if you`re looking for
sunshine in the coast and valleys. Onshore flow to the east and
north remains virtually the same all week, and with some cooling
aloft moving in with the upper low about the only chance for
afternoon clearing is if the marine inversion deepens so much that
it`s too weak to support a solid cloud layer. Those scenarios are
difficult to predict in advance but given the pattern it is a
possibility, more likely Tue and/or Wed. Some morning drizzle is
possible the next few days as well, especially near the coastal
mountain slopes. In fact, there are several ensemble members (more
from the EPS) showing some very light precip Mon and Tue
mornings, mainly south of Pt Conception. Temperatures will be
similar to today, 5-10 degrees below normal.

.LONG TERM (THU-SUN)...28/1236 PM.

That first upper low this week will be quickly followed by another
one Thursday, likely maintaining or even enhancing an already deep
marine layer with local drizzle possible and minimal change in

Following that a majority of the ensembles do show slight
improvement into next weekend with ridging developing along the
West Coast, though once again strongest much farther north over
the Pac NW. However, there is a 20-30 percent chance that the
trough will linger across southern California and result in little
or no chance in daytime highs. The most likely scenario is
temperatures warming to within a couple degrees of normal (ie.
still slightly below normal) with continued night through morning
low clouds and fog for coast/valleys.



At 2200Z, the marine inversion as KLAX was based at 3300 feet.
The top of the inversion was 5100 feet with a temperature of
14 degrees Celsius.

Overall, moderate to high confidence in 00Z TAF package. For
coastal and valley sites, moderate confidence in latest TAFs
with MVFR CIGs expected for all sites with a 20-40% chance of IFR
CIGs (except high confidence in IFR CIGs for KPRB overnight).
There is a 20-30% chance that MVFR CIGs will scatter out after
20Z. High confidence in desert TAFs.

KLAX...Overall, moderate confidence in 00Z TAF as MVFR conditions
are anticipated through the period. There is a 20-30% chance of
IFR CIGs 08Z-15Z. There is a 20-30% chance that MVFR CIGs will
scatter out after 20Z. No significant easterly wind component is

KBUR...Overall, moderate confidence in 00Z TAF as MVFR conditions
are anticipated through the period. There is a 30-40% chance of
IFR CIGs 08Z-15Z. There is 20-30% chance that MVFR CIGs will
scatter out after 20Z.


.MARINE...28/121 PM.

For all waters, high confidence in current forecast through
Wednesday. For this period winds and seas are expected to remain
below Small Craft Advisory (SCA) levels.

Moderate confidence that Wednesday night widespread SCA level
winds, and borderline SCA level seas will spread over the outer
waters and the western portion of the Santa Barbara Channel.


.BEACHES...28/121 PM.

Long-period south swell originating from the Southern Hemisphere
will move into the coastal waters through Tuesday. Strong rip
currents and elevated surf of local 3 to 5 feet will be possible
over the Memorial Day holiday weekend. There will be the potential
for hazardous rip currents and a Beach Hazards Statement may be
needed later this weekend.






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