Acton Weather

000
FXUS66 KLOX 052121
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
221 PM PDT Mon Jun 5 2023

.SYNOPSIS...05/219 PM.

A low pressure system will bring much cooler weather through
Wednesday, along with a chance of showers and thunderstorms. A
cooler air mass is likely to remain through the rest of the week
with extensive low clouds and possible drizzle during the night
and morning hours.

&&

.SHORT TERM (TDY-THU)...05/210 PM.

Our first storm fired up right near the SLO/Santa Barbara/Kern
triple point and is moving northwest into southeastern SLO County.
This should be the first of many convective cells that develop
through early Tuesday, focusing on SLO County and the far
northern part of SB County. PG&E cameras indicate not much is
reaching the ground so far, in line with the forecast soundings
showing LCL`s in the 8-10k feet level. However, overnight the
LCL`s are expected to drop to around 5-7k feet, and PW`s are
expected to increase to close to 1.2" which is around 250% of
normal. So there is plenty of moisture available and with CAPE`s
around 2000j/kg and lapse rates around 9c/km there is the
potential for some strong storms overnight. Primary concerns will
be heavy rain, gusty winds (DCAPEs between 600-1000j/kg), and
frequent lightning. Storms will be moving in from the east and
should continue on to the coast and over the adjacent coastal
waters. Virtually all the ensemble members are still showing rain
across that area tonight so confidence is on the high side.

Elsewhere activity is expected to fairly minimal. Stability
parameters are considerably less favorable across LA County. Main
forecast issue there is the deep marine layer and possible
overnight drizzle/light rain. Could see that tonight and/or
Tuesday night. Temperatures will remain well below normal
everywhere with the combination of storms and marine layer.

The upper low will wobble around the area through Wednesday and is
expected to exit to the east by Wednesday night. Latest models
continue to favor SLO and northern Santa Barbara Counties for some
additional showers and possible storms Tuesday night into early
Wednesday. However, lower confidence in this as a lot depends on
exactly where the upper low drifts to. Can`t rule out an isolated
storm over the mountains and into the Antelope Valley on
Wednesday, though forecast soundings are still not favorable for
those areas.

Another deep marine layer day Thursday with slow clearing and cool
temperatures. With the low expected to be east of the area by then
chances for afternoon thunderstorms are minimal.

.LONG TERM (FRI-MON)...05/218 PM.

The cooler than normal pattern is expected to continue into early
next week as another upper low moves in this weekend. This one is
approaching from the northwest but still has some moisture with
it. Although rain chances are mostly under 10 percent currently,
it`s possible those will rise as we get closer to the weekend and
have more confidence in the orientation and track of the low as
well as the moisture content. It`s also possible that
thunderstorms will be added to the forecast. At the very least
there is high confidence in a continued cool pattern with a
possibility of early morning drizzle for coast/valleys.

&&

.AVIATION...05/1913Z.

At 1815Z, the marine inversion at KLAX was based at 4300 feet.
The top of the inversion was 5200 feet with a temperature of 14
degrees Celsius.

Low confidence in the 18Z TAF package. A low pressure
system directly overhead is causing some havoc and uncertainty
regarding cloud cover and the threat of showers and isolated
thunderstorms. Deepening marine layer will likely keep
coastal/valley sites cloudy through the day, with little
confidence in timing of flight category changes, due to multiple
cloud layers. North of Point Conception, there is a 20-25% chance
of thunderstorms at TAF sites from this afternoon through tonight.
Gusty winds are expected in the Antelope Valley.

KLAX...Low confidence in 18Z TAF. There is a 30% chance that VFR
CIGs could develop 20Z-03Z. There is a 20% chance of a light
shower. No significant easterly wind component is expected.

KBUR...Low confidence in 18Z TAF. There is a 20% chance that VFR
CIGs could develop 21Z-03Z. There is a 20% chance of a light
shower.

&&

.MARINE...05/852 AM.

For the Outer Waters, high confidence in current forecast.
Today through Friday, winds and seas will remain below Small
Craft Advisory (SCA) levels.

For the Inner Waters north of Point Sal and the Inner Waters
south of Point Conception, high confidence in current forecast.
Today through Friday, winds and seas will remain below SCA
levels.

From this afternoon through Tuesday morning, an upper level
low pressure system will bring a slight chance of thunderstorms
to the area, mainly north of Point Conception.

&&

.BEACHES...05/1150 AM.

A south swell of 2 to 4 feet with a 16 second period will arrive
on the south facing beaches today and Tuesday. At the same time,
a full moon tide of near 7 feet is expected into this evening. At
this time, local wave sets of 5 feet may be possible, but minor
coastal overflow at the time of high tide is not expected to
affect any areas of the coast.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...MW
AVIATION...Sweet/RAT
MARINE...Sweet/RAT
BEACHES...Sweet/RAT
SYNOPSIS...MW

weather.gov/losangeles

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