Acton Weather

450
FXUS66 KLOX 271302
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
602 AM PDT Sat Jul 27 2024

.SYNOPSIS...27/407 AM.

Cooler temperatures are expected this weekend as high pressure
aloft weakens. High temperatures will drop to 4 to 8 degrees
below normal across the region, with an increase in morning low
clouds and fog for coasts and some valleys. Locally gusty winds
are expected during the afternoon and evening for the Santa
Barbara southwestern coast and the Antelope Valley. Starting
Monday, temperatures will gradually trend warmer each day.

&&

.SHORT TERM (TDY-MON)...27/410 AM.

This weekend will feature a cooling trend, with temperatures
below normal across the region. 500 mb heights will hold
consistent and on the low side, kept at bay by a trough moving
across the northern part of California. Today temperatures will
drop dramatically to around 3 to 7 degrees below normal (near
normal for DTLA), followed by another couple of degrees of
cooling likely for Sunday. Expect highs this weekend to be in the
upper 60s to around 80 for the beaches and coastal plains, in the
80s to low 90s for the valleys and foothills, and mid 90s for the
deserts. Monday, as a broad high pressure system starts to develop
over the central southern United States, 500 mb heights for SoCal
will creep up slightly. Temperatures are likely to increase by a
couple degrees Monday, especially across inland areas, however
will still be several degrees below normal.

Strong onshore and north-to-south pressure gradients will drive
gusty winds for wind prone areas, especially today and tonight.
Across the Antelope Valley and adjacent foothills, southwest wind
gusts of 20 to 40 mph will be common this afternoon and evening.
Sundowner winds are expected to continue this afternoon through
tonight across the Santa Barbara Southwestern Coast, with
northwest wind gusts of 25 to 40 mph. Both the Sundowner and the
Antelope Valley winds may repeat on Sunday and Monday, but
pressure gradient trends indicate that they are likely to be
slightly weaker. At this time, no wind advisories are anticipated
to be needed.

The atmosphere will continue to dry over next few days, with no
significant source of moisture for inland ares. Despite much
cooler temperatures this weekend, low humidities and the
previously mentioned gusty winds will drive fire weather
concerns. Fire weather risk will correspond with the strongest
wind, thus is highest across the Antelope Valley and adjacent
foothills, and the Santa Barbara Southwestern Coast. Members of
the public are encouraged to remain cautious with any sources of
fire starts and residents are urged to stay on alert this weekend.

.LONG TERM (TUE-FRI)...27/526 AM.

Through Wednesday the broad high pressure system will remain
stationary, centered over Texas and adjacent states. By Thursday
it is likely to travel northwest, settling over the Four Corners
on Friday. There is good agreement among the ensembles in this
pattern. For SoCal, 500 mb heights will increase gradually each
day with this pattern, resulting in a slow warming trend of a
couple degrees each day. At this time, no significant heat impacts
are expected through mid next week, with highs just starting to
reach normal on Wednesday. Thursday and Friday conditions return
to several degrees above normal for areas away from the coast.

Thursday and Friday, due to the the location of the high pressure
system, there is chance of significant monsoonal moisture
reaching the region. Moist southeast flow aloft is favored by the
latest deterministic GFS. Isolated thunderstorms or showers are
possible for northeastern Los Angeles County (Antelope Valley and
mountains) on Thursday (5 percent chance) and Friday (10 percent
chance). There is the potential Friday for shower/thunderstorm
chances to extend west into the Ventura County Mountains and south
towards the coast, depending on the extent of the moisture.

&&

.AVIATION...27/1301Z.

At 12Z at KLAX, the marine layer was 1100 feet deep. The top of
the inversion was around 4200 ft with a temp of 24 C.

Low clouds were fairly widespread on the Central Coast and in the
Santa Ynez/Salinas Valleys. S of Pt Conception, clouds were
confined to immediate coastal areas from southeastern SBA County
thru L.A. County and were sneaking into the San Gabriel Valley.
Conds were mostly LIFR to VLIFR. Skies should clear by mid morning
in all areas, except possibly as late as noon at a few beach
locations. Low clouds should be widespread in most coastal areas
tonight, with clouds also likely in the Santa Ynez, Salinas and
San Gabriel Valleys. Expect mostly LIFR to VLIFR conds, except IFR
conds in L.A. County coastal areas.

KLAX...Low to moderate confidence in the TAF. There is a 20%
chance that conds will remain VFR this morning. There is a 20%
chance that cigs will scatter out as early as 16Z. There is a
20-30% chance that there will be no clouds tonight. No significant
easterly wind component is expected thru the pd.

KBUR...High confidence in CAVU TAF.

&&

.MARINE...27/602 AM.

In the Outer Waters, moderate confidence in the forecast. In the
southern zones (PZZ673/676), high confidence in Small Craft
Advisory (SCA) level winds continuing thru Sun night. For Mon,
there is 40% chance of SCA level winds, then SCA level winds are
likely (60-70% chance) Mon night thru Wed night. In the northern
zone (PZZ670), SCA level winds are likely thru tonight. There is a
40% chance of SCA level winds Sun thru Tue morning, then SCA
conds are likely (70% chance) Tue afternoon thru Wed night.

For the Inner Waters N of Pt. Sal, moderate confidence in the
forecast. SCA level winds are likely (60-70% chance) this
afternoon/eve. There is a 30-40% chance of SCA level winds during
the afternoon/eve hours Sun thru Mon night, then SCA winds are
likely during the afternoon/eve hours Tue thru Wed night.

For the Inner Waters S of Pt. Conception, moderate confidence in
the forecast. Across western portions of the Santa Barbara
Channel, SCA conds are likely (60-70% chance) late this afternoon
thru late tonight, and there is a 30% chance of SCA level winds
during the late afternoon thru late night hours Sun thru Tue.
Otherwise, SCA conds are not expected thru Wed night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from noon today to 9 PM PDT
      this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Sunday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Sunday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Monday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Schoenfeld/DB
AVIATION...DB
MARINE...DB
SYNOPSIS...MW/RS

weather.gov/losangeles

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