Lomita Post Office, California Weather Forecast Discussion

993
FXUS66 KLOX 082159
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
259 PM PDT Mon Sep 8 2025
.SYNOPSIS...08/111 PM.
A significant cooling trend will begin today as a low pressure
system approaches northern California. This will result in much
cooler temperatures across Southwest California by Wednesday and
Thursday. In addition, marine layer clouds will expand across
coastal areas and well inland over the valleys with morning
drizzle possible through Friday. A small warming trend is then
expected Friday into the weekend.
&&
.SHORT TERM (TDY-THU)...08/256 PM.
An upper level low pressure system is moving into northern
California today and will camp out over that area through
Wednesday, while an associated trough slowly moving over SW
California. On Thursday, the low slowly starts to shift NE out of
northern CA while the trough actually digs more southward over SW
CA. As a result, 500 mb heights will drop from 590 dam to 580 dam
by Wednesday and down to 578 dam (10 dam below normal for this
time of year) on Thursday.
With lowering heights and a deepening marine layer already
starting, high temperatures have already seen cooling compared to
yesterday. With onshore flow strengthening to 7mb on Tuesday,
further cooling is expected across the region, with highs dropping
by 2 to 4 degrees across the coast and 5 to 10 locally 12 degrees
across the valleys. On Wednesday, another 2 to 5 degrees of
cooling will be possible as well. With the temperatures dropping
each day, the valleys (who have high temps reaching the upper 80s
to mid 90s today) will end up in the upper 70s to mid 80s by
Wednesday.
The marine layer will deepen Tuesday and up to 3000 ft on Wednesday
thanks to the falling heights and continued onshore flow (for the
most part). Drizzle will be possible during the late night to
morning periods as early as Tuesday and continuing through Friday.
However, additional lift provided by the trough (vort lobe moving
through) will allow the marine layer to further deepen on
Wednesday, meaning the best chances for drizzle will be Wednesday
morning and some measurable light rain might even occur across the
coasts to the coastal slopes/foothills. Low clouds and fog will
likely push into the valleys overnight toward dawn (though the
lack of clouds south of Point Conception the last few nights does
introduce uncertainty in the forecast for those areas, and there`s
a 30% chance Ventura and Los Angeles remain cloud free tonight
into tomorrow). However for southern Santa Barbara, gusty
advisory level sundowner winds will affect the SW portion of Santa
Barbara County during the evening and overnight hours tonight and
Tuesday night, which will help keep the clouds away from the SBA
south coast.
In addition to the sundowner winds, gusty SW winds during the
afternoon and evening hours for the San Gabriel Mountains and
Antelope Valley this week. These winds will peak on Tuesday, and
a wind advisory was issued for the eastern San Gabriel Mountains
and the entire Antelope Valley foothill locations Tuesday morning
through mid-evening. These areas could see wind gusts up to 50
mph, and locally up to 55 mph across higher elevations.
Otherwise, most coastal locations will see breezier onshore winds
than a typical day, but still remain well under advisory levels.
On Thursday, once again there will be plenty of morning low
clouds and maybe some more drizzle. Max temps will continue to
run 3 to 6 degrees below normal at the coasts and 5 to 10 degrees
below normal in the valleys.
.LONG TERM (FRI-MON)...08/256 PM.
The upper low will move out on Friday, with a weak ridge building
in behind the trough over SW California on Saturday. Like a
broken record repeating itself, Friday will start out cloudy
across the coasts and valleys, but the clearing will be a little
faster. Slightly higher heights and slightly faster clearing will
bring 1 or 2 degrees of warming to the area.
The weak ridge on Saturday will bring 500 mb heights up to 585
dam, and while there will not be much change in the onshore flow,
the higher heights may shrink the marine layer enough to keep it
out of most of the valleys with clearing of clouds noticeably
faster across the region compared to earlier in the week. Max
temps will respond with 2 to 4 degrees of warming, bringing a few
readings in the lower 90s to the warmest valley locations.
Despite the 2 days of warming, max temps will still be around 2
to 4 locally 6 degrees below normal.
Not much change slated for Sunday as another weak trough starts to
move into the region, but the heights really don`t change much.
&&
.AVIATION...08/1916Z.
At 1821Z at KLAX, the marine layer was 600 feet deep. The top of
the marine inversion was near 2200 ft with a temperature 23 C.
Moderate confidence in TAF. Wind speeds may be off by 5 kt during
peak winds across the deserts. Arrival cigs may be off by +/- 3
hours tonight, especially south of Point Conception. Flight
category may be one category lower than forecast at times.
KLAX...Moderate confidence in TAF. There is a 15% chance of no
cigs developing tonight, and cigs may arrive as early as 06Z and
as late as 13Z, with heights between OVC008-BKN018. No significant
east wind expected.
KBUR...High confidence in TAF until around 10Z, then there is a
30% chance of BKN008-015 cigs.
&&
.MARINE...08/157 PM.
For the Outer Waters south of Point Sal, Small Craft Advisory
(SCA) northwest winds are expected through at least Saturday,
with brief lulls possible during the morning hours. North of
Point Sal (including the nearshore waters) there is a slight
chance of SCA winds Tuesday afternoon/evening, becoming likely by
late Wednesay evening, lasting much of the time through Saturday.
Seas will peak at around 6 to 8 feet Thursday through the weekend.
South of Point Conception, areas of SCA level west winds are
likely each afternoon and evening through Wednesday night,
especially across the Santa Barbara Channel, near Point Dume, and
across the San Pedro Channel. Choppy wind driven seas are likely
to peak Wednesday night at around 5 to 7 feet. Chances for SCA
winds (50 percent) will remain through Saturday.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect from 6 PM this evening to 5
      AM PDT Tuesday for zones 349-351. (See LAXNPWLOX).
     Wind Advisory in effect from 10 AM to 9 PM PDT Tuesday for
      zones 380>382. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 5 AM PDT Tuesday for
      zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 6 PM to 9 PM PDT this
      evening for zone 655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Lund/Rorke
AVIATION...Schoenfeld
MARINE...Schoenfeld
SYNOPSIS...CC/KL
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

NWS LOX Office Area Forecast Discussion