Wind Advisory 4, NWS Los Angeles, CA

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
521 AM PST Fri Jan 5 2024

.SYNOPSIS...05/244 AM.

Gusty northerly winds over wind-prone locations will continue
through this morning, especially through and below passes and
canyons. Otherwise, dry and cool conditions are expected for most
areas through Saturday. Then, a storm system will bring strong to
damaging winds to portions of the region Saturday night through
the weekend. Any precipitation with the storm should be light,
except along the north slopes including the Interstate-5
Grapevine, where a couple inches of snow could occur.

&&

.SHORT TERM (TDY-SUN)...05/520 AM.

There were some areas of low clouds across interior portions of
SLO/SBA Counties early this morning, and plenty of high clouds
across the region. Today should start out partly to mostly cloudy,
but there should be a decrease in clouds this afternoon. Most
areas are expected to be mostly sunny this afternoon. Gusty north
winds continued at advisory levels in the mtns of L.A., VTU and
SBA Counties including the Santa Ynez Range, but winds should
decrease below advisory levels in most areas by late morning.
There were some pockets of frost or freezing temps in the Ojai
Valley and in the Agoura Hills/Calabasas area this morning, but
temps should climb fairly quickly after sunrise. Max temps may be
up slightly today, with highs in some of the warmer locations
approaching 70 degrees, just about normal for this time of year.

A northwesterly flow pattern aloft will continue across the
forecast area thru tonight. A short wave trough embedded in the
fast northwesterly flow will zip southeastward into the Great
Basin later today and tonight. This will cause winds aloft to
strengthen again tonight, and there will be some cold air
advection and increasing subsidence. In addition, N-S gradients
will increase a bit. This should cause N winds to increase this
evening, possibly getting close to advisory levels across the
mtns, portions of southern SBA County and thru the I-5 Corridor.
Low level flow will turn more northeasterly late tonight and Sat
morning, which will shift the focus of the winds briefly to
portions of L.A./VTU Counties prone to Santa Ana winds. Winds
could get close to advisory levels in these areas for a brief
period late tonight/Sat morning. However, for the most part,
expect winds to remain just below advisory levels.

Where winds drop off tonight, it will be very chilly and light
freezes are possible in the Ojai Valley and wind sheltered
portions of the Agoura Hills/Calabasas area. A Freeze Watch is in
effect for these areas late tonight and early Sat.

An upper low will drop southward along the coast of British
Columbia and into the Pacific NW Sat, causing the westerly jet to
sag southward down the West Coast. Expect skies to be mostly
sunny Sat, but mid and high clouds may increase during the day,
especially north of Pt. Conception. Heights will fall, but
offshore flow to start the day should offset cooling. So, expect
max temps Sat to be similar to those of today in most areas.

The trough in the Pacific NW will slide southeastward thru Nevada
and western Utah by late Sat night, then pinch off into a closed
upper low near the Four Corners area Sun afternoon. This will
result in very strong and cold northwest to north flow aloft
across the region Sat night/Sun. The southern end of a weakening
surface front may bring a band of very light rain from northwest
to southeast across the region Sat night, with measurable
precipitation most likely north of Pt. Conception, in the
mountains, and across eastern L.A. County. Snow levels will drop
below 3500 feet by late Sat night. On Sun, moist upslope northerly
flow will keep a chance of snow showers in the mountains thru Sun
morning, particularly on northern slopes. Snow levels will drop
to 3000 feet or possibly even lower Sun morning. Where measurable
rain does occur, totals should be one tenth of an inch or less in
most areas, except locally higher precipitation amounts are
possible on north slopes of the mountains. There could be a couple
of inches of snow in the mountains, and possibly across higher
portions of I-5, with a dusting of snow possible in the foothills
of the Antelope and Cuyama Valleys. Otherwise, skies will become
partly cloudy to mostly sunny Sunday and it will be very chilly,
with temps 6 to 12 degrees below normal in most areas.

This system will mainly be a strong wind-maker for the forecast
area. Expect widespread strong west to north winds across much of
the region Sat night into Sun evening. Models still show a
favorable combination of strong winds aloft, steep north to south
gradients, impressive subsidence and good cold air advection
across the region, with the upper jet in a favorable location.
High Wind Watches are in effect for the interior mtns of SBA
County, the Santa Ynez Range, the mtns of VTU County, the mtns of
central and western L.A. County including the I-5 Corridor, and
the Santa Clarita Valley. The High Wind Watch may have to be
expanded into the western San Fernando Valley, the eastern Ventura
County Valleys, the Santa Monica Range, and the Malibu Coast.
This pattern is also favorable to produce mountain wave activity
in the eastern San Gabriel mtns, which could push damaging gusts
briefly into the foothills above the San Gabriel Valley. As we get
closer to the event, Wind Advisories will likely be needed for
many other areas. Winds should slowly subside Sun night. It will
be very cold Sun night, especially in areas where winds subside.

.LONG TERM (MON-THU)...05/514 AM.

The upper low will move eastward into north Texas and Oklahoma on
Mon. The strong northwest flow aloft over the region will relax
as a weak ridge builds into CA. Skies will be mostly sunny Mon,
and after a cold night, max temps will rebound nicely. Although
max temps may be up Mon, they should still be a few degrees below
normal in most areas.

The weak ridge will be short-lived, as an upper low moves into the
Pac NW Tue, causing the flow aloft to become zonal, and causing
heights to fall a bit. Skies will be clear Mon night, and with
clear skies, light winds and a lingering cold air mass, it could
be one of the coldest nights in many areas this season. Despite
falling heights Tue, temps at low levels will moderate, and skies
will be sunny, so expect max temps Tue to be about the same as
they are on Mon.

The upper low in the Pac NW will track to the north and east of the
region Wed, then into the Great Basin and Rocky Mountains Thu. There
will be broad cyclonic flow aloft over the region during mid week.
Expect an increase in clouds Wed, and there is a slight chance of
rain or showers Wed night/Thu as some moisture tries to sag
southward into the region. At this point, it appears as though
rain, if any, will be on the light side. It will be cooler during
the days, especially Thu, with temps several degrees below normal.

&&

.AVIATION...05/1314Z.

At 1148Z at KLAX, there was no marine layer nor inversion.

High confidence in VFR TAFs, except moderate confidence in KPRB where
there is a 50% chance of VLIFR conds through 17Z. With respect to
winds, there is moderate confidence in current forecasts with +/-
3 hour window for wind shifts.

KLAX...High confidence in TAF. No significant easterly wind
component is expected.

KBUR...High confidence in TAF. Moderate confidence in wind
forecast with +/- 3 hour window for forecast wind shifts.

&&

.MARINE...05/510 AM.

For the Outer Waters, high confidence in current forecast. Tonight
through Friday night, Small Craft Advisory (SCA) level winds and
seas will continue, with local gale force gusts south of the
Channel Islands to San Nicolas Island through this morning. Winds
may drop below advisory levels Saturday morning, but by late
Saturday afternoon through Sunday night, high confidence in Gale
Force winds and 10+ foot seas. For Monday and Tuesday, high
confidence in SCA level winds.

For the Inner Waters north of Point Sal, high confidence in
current forecast. SCA level seas will continue through Sunday. On
Saturday, northwest winds will increase with Gale Force levels
likely late Saturday afternoon through Sunday night. For Monday
and Tuesday, winds and seas will remain below SCA levels.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. Modeate confidence in SCA level
winds across the western half of the Santa Barbara Channel.
Elsewhere, winds and seas are expected to remain below SCA level
although there is a 40-50% chance of SCA level northeast winds
Friday night nearshore from Ventura to Santa Monica. Saturday
afternoon through Sunday night, west to northwest winds will
increase with a 60-70% chance of Gale Force winds across all the
southern Inner Waters. Sunday night to mid Monday morning, there
is a 30% chance of north to northeast winds from Ventura to Santa
Monica and possibly into the San Pedro Channel. Otherwise, high
confidence in winds and seas remaining below SCA levels Monday
and Tuesday.

&&

.BEACHES...05/515 AM.

A long period, large swell will bring high to elevated surf to the
coasts through the weekend. High surf will continue for the
Central Coast (12-20 feet) through the weekend, with surf
increasing to advisory levels across Ventura County beaches (7-10
feet) Saturday through the weekend. There is a 30% chance of high
surf (5-8 feet) for the Los Angeles County Coast and Santa
Barbara South Coast Sunday into Monday morning. Surf will again
be strongest for west and northwest facing beaches.

During the morning high tides Saturday through Monday morning,
there is a moderate risk of minor coastal flooding across the
Central Coast, peaking Sunday. There is a chance of minor nuisance
coastal flooding for the Ventura Coast Sunday morning.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Watch in effect from late Saturday night through
      Sunday evening for zone 88. (See LAXNPWLOX).
     High Surf Advisory in effect until 9 AM PST Monday for zones
      340-346. (See LAXCFWLOX).
     Wind Advisory in effect until 10 AM PST this morning for
      zones 349-351>353-376>379. (See LAXNPWLOX).
     High Wind Watch in effect from Saturday evening through
      Sunday evening for zones 351>353-376>379-549-550. (See LAXNPWLOX).
     High Surf Advisory in effect from 2 AM Saturday to 9 PM PST
      Sunday for zone 354. (See LAXCFWLOX).
     Freeze Warning in effect until 9 AM PST this morning for zone
      357. (See LAXNPWLOX).
     Freeze Watch in effect from late tonight through Saturday
      morning for zones 357-371. (See LAXNPWLOX).
     Frost Advisory in effect until 9 AM PST this morning for zone
      371. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PST Saturday for
      zones 645-670-673-676. (See LAXMWWLOX).
     Gale Watch in effect from Saturday afternoon through late
      Sunday night for zones 645-650-655-670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 PM PST this evening
      for zone 650. (See LAXMWWLOX).

&&

PUBLIC...DB
AVIATION...Lund
MARINE...RAT/Lund
BEACHES...Lund/RAT
SYNOPSIS...Cohen/KL

weather.gov/losangeles

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