Acton Weather

000
FXUS66 KLOX 010400
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
800 PM PST Tue Jan 31 2023

.SYNOPSIS...31/716 PM.

Santa Ana winds will continue through Wednesday over Los Angeles
and Ventura Counties, but likely below advisory level. Chilly
temperatures are expected each morning in the coldest locations
through Thursday, with the lowest temperatures Wednesday morning.
A slow warming trend is expected through Saturday. Light rain is
possible north of Santa Barbara Saturday night into Sunday
morning, followed by gusty north to northeast winds early next
week.

&&

.SHORT TERM (TUE-FRI)...31/715 PM.

***UPDATE***

Santa Ana winds are on their way down this evening and all wind
headlines have been allowed to expire. Some of the typically
windier spots such as Magic Mountain Truck Trail are still
gusting in the 40 mph range. Otherwise gusts through the Santa Ana
wind corridor away from the coast are gusting mainly below 30
mph. The offshore winds have allowed clear skies with not a cloud
anywhere nearby according to satellite imagery. Spots that will
be sheltered from wind will be quite chilly tonight thanks to the
clear skies and dry air. Frost Advisories will be in effect
tonight for the Central Coast, Santa Ynez Valley, Santa Barbara
South Coast, and Ojai Valley with lows of 32 to 35 expected. The
Antelope Valley will be even colder, with lows in the 20s
expected, thus a Hard Freeze Warning will be in effect. Areas that
will see some wind will likely be moderated with lows in the 40s.

Heights are expected to rise on Wednesday as a ridge nudges in
from the Eastern Pacific. Gradients remain offshore, but are
trending weaker from today. This should keep the northeast winds
going across Los Angeles and Ventura Counties. Upper-level support
is trending weaker as well, so in all expecting a weaker wind
event than today. Fairly good confidence winds will widely be
below advisory level, with gusts of 25 to 45 mph peaking Wednesday
morning. As is typical, those outlier windier spots may gust
higher. The ridging and weaker offshore flow will combine to bring
a bit of warming to the region with highs in the mid- to upper-60s
across the Ventura and Los Angeles metro areas.

***From Previous Discussion***

Otherwise, pretty quiet weather now through Friday. Daytime highs
will slowly warm through the period, reaching the low 70s by
Friday. Increasing high clouds Thursday ahead of the next weather
system becoming mostly cloudy by Thursday night. Models have
really scaled back on this first of two systems for later this
week and now only a small percentage have rain even for SLO
County. So pops have been reduced to under 15% all areas Friday
and rain has been removed from the official forecast.

.LONG TERM (SAT-TUE)...31/157 PM.

Another mild day Saturday with highs reaching the lower 70s across
the warmer valleys. The second of two systems will be approaching
from the west leading to increasing clouds along the Central Coast
through the day. While models scaled back the rain chances with
the first system Friday, the number of ensemble members showing
rain for Sunday north of Pt Conception continues to grow. Pops
remain on the lower side though given the lack of model stability
run to run but at least for the SLO and northern Santa Barbara
Counties chances for rain there Sat night into Sunday are looking
more favorable. Still rather light with most areas at or under a
third of an inch.

Farther south it`s quite a bit less likely for any sort of
meaningful rain. Deterministic runs show a front coming through
LA/Ventura Counties very early Sunday with little if any
southerly flow. With most of the storm energy well to the north
and not much upslope flow to help out probably the most that can
be expected would be some drizzle or very light precip that may
not even measure. Best chances would be eastern LA County due to
somewhat more favorable low level flow there up against the San
Gabriels.

The front is through the area Sunday afternoon with clearing
skies and much cooler temperatures.

Following the frontal passage increasing north to northwest winds
are expected late Sunday into early Monday, especially in the
mountains. Then shifting to northeast late Monday into Tuesday,
possibly leading to advisory level Santa Ana`s in some areas. The
offshore flow will help temps warm up several degrees across coast
and valleys.

&&

.AVIATION...01/0048Z.

At 0024Z at KLAX, there was no marine layer.

High confidence in TAFs. Periods of moderate to strong turbulence
and LLWS are possible at Ventura and Los Angeles County terminals
through the evening.

KLAX...High confidence in TAF. There is a 20% chance of north
winds of 10 kt through 05Z. Any east winds will be less than 7
knots.

KBUR...High confidence in TAF. Moderate to strong turbulence and
LLWS are possible through the evening.

&&

.MARINE...31/758 PM.

Moderate confidence in the current forecast.

For the waters along the Central Coast and the outer waters south
to Santa Cruz Island, winds and seas will very likely remain
below Small Craft Advisory (SCA) levels through at least Thursday
morning. There is a 20% chance of north to northwest SCA level
winds south of Point Conception briefly on Wednesday afternoon. An
increasing chance of widespread SCA conditions will develop over
the weekend with a 60-80 percent chance of at least SCA conditions
between Saturday and Monday. There is a 20-40 percent chance of
GALES developing, highest between Saturday night and Sunday night.

Inside the southern California bight and southeast of San Nicolas
Island, SCA level winds will continue for the nearshore waters
between Point Mugu and Santa Monica through Wednesday morning.
These winds will create short period, hazardous seas during this
time. It is possible that winds drop below SCA levels for the
majority of the area and remain confined to the extreme nearshore
waters from Point Mugu to Malibu tonight into Wednesday morning.
Thus the SCA may be cancelled early. Better confidence with winds
and seas dropping below SCA levels between Wednesday afternoon
and Sunday. However, there is a 20% chance of brief NW SCA level
winds from Santa Cruz Island south to San Nicolas Island Wednesday
afternoon. Then, there is a 40 percent chance of widespread SCA
conditions between Sunday and Monday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Hard Freeze Warning in effect from 1 AM to 8 AM PST Wednesday
      for zone 59. (See LAXNPWLOX).
     Frost Advisory in effect from 1 AM to 8 AM PST Wednesday for
      zones 340-341-346>350-357. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until noon PST Wednesday for
      zone 655. (See LAXMWWLOX).

&&

$$

PUBLIC...Stewart/MW
AVIATION...Stewart
MARINE...Sweet/Lund
SYNOPSIS...Stewart

weather.gov/losangeles

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