618
FXUS66 KLOX 011144
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
444 AM PDT Sat Jun 1 2024

.SYNOPSIS...01/337 AM.

A persistent marine layer with cooler than normal weather will
remain in place through the weekend as strong onshore flow
continues across the area. High pressure aloft will build in next
week, weaken onshore flow, and bring a warming trend to area. The
hottest temperatures are expected for the interior portions of
the area Tuesday through Thursday.

&&

.SHORT TERM (TDY-MON)...01/442 AM.

Strong onshore flow remains in place across the area early this
morning as a weak upper-level trough of low pressure moves over
the region. It should be of no surprise that low clouds and fog
are well-entrenched again this morning. Earlier AMDAR soundings
from KLAX indicated a marine layer depth near 1900 feet deep, but
judging by the expanse of the low cloud field, it is likely
closer to 2500 feet deep currently. Instability with the upper-
level trough has squeezed out some drizzle across portions of
southern and central California this morning. There are a few
rain gages picking a hundredth or two, and drizzle is occurring
at our office early this morning and wetting pavement surfaces.
Roads may be slick this morning due the lack of rain over the last
month, so if heading out this morning, please take a few extra
minutes to reach your destination safely.

A cooler than normal weather pattern is expected to persist through
the weekend as strong onshore flow will remain in place. The
forecast remains near persistence along the coast while
continuing a cooling trend across the interior portions of the
area. Low clouds will likely struggle to clear again today, but
there is a moderate chance that southern Santa Barbara County and
the Ventura County coast could break out of the low clouds this
evening as a northerly surface pressure gradient develops.
Statistics favor portions of the area breaking out of the clouds
late this afternoon and evening, but May Gray has had its grip on
the region with the month of May finishing out cooler than
normal. June is shaping up to start similarly.

Strong onshore pressure gradients will develop gusty onshore winds
in the Antelope Valley and adjacent foothill areas this afternoon
and evening. The latest forecast guidance puts KPMD and KWJF in
the range of advisory outcomes, and a wind advisory was added from
noon today to 9 pm. Certainly, the strongest winds will be
expected in wind-favored locations, such as Lake Palmdale and
Sierra Pelona.

A wind advisory was also added for southwestern Santa Barbara
County tonight as the trough passing by will bring a tightening
northerly pressure gradient. Gusty Sundowner winds will develop
tonight, strongest west of Goleta out toward Gaviota and Refugio
State beaches in the evening. As the northerly pressure gradient
will remain in place for Sunday night and again Monday night, wind
advisories may be needed again the next several nights, possibly
spreading east into the southeastern portion on Monday night. EPS
ensemble members continue to suggest advisory level winds
developing for KSDB on Monday night and into Tuesday morning.

With the trough passing by, high pressure aloft will build into
the region on Monday. A warming trend will establish and the
region will start to heat up.

.LONG TERM (TUE-FRI)...01/444 AM.

The warming trend will turn more significant away from the coast
across the interior portions Tuesday through Thursday. Broad
troughing over the region will dig south of the border and carve
out a cutoff low into the middle to late next week. An upper-level
ridge will nose into southeast California. The air mass will heat
up away from the coast. The latest NBM solutions suggest an 80 to
90 percent chance of KPMD and KWJF hitting the 100 degree mark by
Wednesday. As well, there are low-to-moderate chances of 100
degree days on Tuesday and Thursday with chances climbing for
later in the week over the previous runs. Closer to the coast, the
marine layer depth will shrink some, but strong onshore flow is
progged to remain in place. Thus, night through morning low clouds
and fog will likely remain a staple of the forecast for the
coastal and valley areas through the period. The beaches and
immediate coastal areas could remain shrouded in clouds into late
next week at times.

While not definite, there is an outside chance that given the
southeast flow aloft, an early start to the southern California
Desert Monsoon Season could begin early. EPS solutions highlight a
5-10 percent chance of precipitation at KGXA, KPMD, and KSDB and
pattern recognition of the deterministic GFS solutions suggest a
pattern consistent with such an outcome. For now, the forecast
goes with NBM values, but there is a non-zero chance for late next
week of afternoon and evening showers and thunderstorms.

&&

.AVIATION...31/2323Z.

At 2230Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was at 5200 feet with a temperature of 21 deg C.

For the 00Z TAF package, high confidence in deserts TAFs as well
as KPRB. For other TAF sites (coastal and coastal valley),
moderate confidence in TAFs. High confidence in return of CIG and
VSBY restrictions for coastal and coastal valley sites, but low to
moderate confidence in timing of flight category changes.

KLAX...Moderate confidence in 00Z TAF. High confidence in CIG/VSBY
restrictions, but moderate confidence in timing of flight category
changes (could be +/- 2 hours of current forecasts). No significant
easterly wind component is expected.

KBUR...Moderate confidence in 00Z TAF. High confidence in return
of CIG/VSBY restrictions, but moderate confidence in timing of
flight category changes (could be +/- 2 hours of current
forecasts).

&&

.MARINE...31/815 PM.

In the northern outer waters zone (PZZ670), SCA winds are
expected to continue through at least Sunday night. Elsewhere in
the outer waters, winds and seas are expected to remain below SCA
levels thru Saturday morning. SCA level winds are likely (70%
chance) in zones 673/676 by starting Saturday afternoon and
continue through at least Sunday night. SCA conds are likely (70%
chance) in all the outer waters Mon and Monday night before
gradually subsiding Tuesday. Conds will likely be below SCA levels
for Wed.

In the inner waters N of Pt. Sal, there is a 30% chance of SCA
level winds Saturday afternoon. SCA conds are likely (60-70%
chance) during the afternoon/eve hours Sun through Mon. Conds
should then be generally below SCA levels Tuesday and Wednesday.

In the inner waters S of Pt. Sal, there is a 40% chance of SCA
winds in western portion of the SBA Channel during the afternoon
and evening hours Saturday through Sunday. Otherwise, conds over
the inner waters should be below SCA levels through Wednesday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 5 PM this afternoon to 3 AM PDT
      Sunday for zones 349-351. (See LAXNPWLOX).
     Wind Advisory in effect from noon today to 9 PM PDT this
      evening for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 2 PM this afternoon to 9
      PM PDT this evening for zones 645-650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 2 PM PDT this afternoon
      for zone 670. (See LAXMWWLOX).
     Gale Warning in effect from 2 PM this afternoon to 3 AM PDT
      Sunday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 2 PM this afternoon to 3
      AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Hall
AVIATION...RAT
MARINE...Gomberg/Sirard
SYNOPSIS...Hall

weather.gov/losangeles

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