Wind Advisory 11, NWS Los Angeles, CA

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
207 PM PST Sat Jan 21 2023

.SYNOPSIS...21/206 PM.

Increasing offshore flow will result in periods of gusty north to
northeast winds through Tuesday. Temperatures will remain below
normal through Tuesday with areas of frost overnight, then near
to slightly above normal the rest of next week.

&&

.SHORT TERM (TDY-TUE)...21/153 PM.

An upper low riding up and over the eastern Pacific ridge will
drop down through the Great Basin and into the Colorado River
Valley Monday morning. The low will deepen to around 537dam as it
moves south while still pulling in additional cold air from the
north. Meanwhile, with a 582dam high just 1000 miles to the west
a very strong north to northeast flow aloft will develop between
the two with the jet core of 120-130kt across eastern LA and
western San Bernardino Counties Monday morning. So the stage is
set for a windy period starting Sunday morning with some gusty
northerly winds across the mountains (mostly advisory level), then
shifting to northeast and increasing Sunday night as the upper
jet core starts to move into the area. The shift to northeast
won't be as quick as models had initially suggested as what was
once a -7.9 LAX-DAG forecast gradient Monday morning has been
reduced to a mere -3.1 with the models today and a -6.9mb LAX-BFL,
meaning there will still be a fairly significant northerly
component even on Monday. Latest 3km model showing some areas of
70mph gusts in the mountains and as earlier discussions have
mentioned some mountain wave activity is possible that could bring
some gusty winds to areas that don't often get them like the San
Gabriel Valley. Probably not to the level of the previous damaging
wind events there but likely stronger than typical offshore
events, especially in the foothills.

With more of a northerly orientation the winds Monday will
focused mostly across western LA County and just barely into the
far eastern portion of Ventura County. Going into Monday night and
Tuesday as the upper low moves east into southern New Mexico and
winds aloft take on a more easterly component surface winds will
veer to the northeast as well and spread more into Ventura County.
Winds expected to be lighter over as well with less upper support.
Current advisories and warnings only go through Monday afternoon
for now, but it's likely that at least advisory level winds will
continue into Tuesday across LA/Ventura Counties with more of a
traditional Santa Ana look and feel to it.

For SLO/Santa Barbara Counties, not too much going on during the
period. Some gusty northerly winds for SB County Sunday and some
breezy northeast Santa Lucia winds Monday and Tuesday.

Given the amount of cold air getting advected into the upper low
this will be a cooler offshore wind event with highs in the low
60s at lower elevations and 40s/50s interior. And wind protected
areas will continue to be at risk for overnight frost.

.LONG TERM (WED-SAT)...21/206 PM.

A brief lull in the winds is expected Tuesday night into Wednesday
before additional cold air drops into the Great Basin
Thursday. ECMWF ensembles showing 45-50mph winds across the
interior Thursday which is a bit strong given the expected
gradient and upper level pattern depicted by the deterministic
models. In any case, another Santa Ana event looks likely
Thursday before weakening Friday. Temperatures will be warming
through at least Friday as the upper high over the eastern
Pacific extends inland to encompass much of California.

A lot of uncertainty after Friday as some solutions, especially
the EPS, start to shift the storm track farther west with some
rain chances by later next weekend.

&&

.AVIATION...21/1752Z.

At 18Z at KLAX, there was no marine layer nor an inversion.

High confidence in CAVU TAFs except there is a 20 percent chance
of IFR or lower cigs/vsbys for KPRB between 10Z-20Z. Lower
confidence in winds, especially after 12Z. Moderate to strong
LLWS may develop as early as 15Z for terminals KSBA and south
including KLAX and KBUR.

KLAX...High confidence in VFR TAF. No significant easterly wind
component is expected there is a 20% chance of a 8 kt easterly
wind component 08-18Z Sun. Moderate to strong LLWS possible after
15Z.

KBUR...High confidence in VFR TAF.

&&

.MARINE...21/147 PM.

A building mixed west to northwest swell and increasing north to
northwest winds will bring Small Craft Advisory to Gale Warning
conditions to all waters save potentially the inner waters
southeast of Santa Barbara by Sunday afternoon. There is a 20-30
percent chance of Gales extending into the inner waters north of
the Channel Islands during this time and a 40-50 percent chance of
SCA conditions building into the inner waters south of Point Mugu
by Sunday evening.

A transition to gusty offshore winds are likely for portions of
the inner waters by Monday, mainly along and south of Point Mugu
with local Gales conditions possible between Point Mugu and Santa
Monica.

Expect steep and choppy seas during periods of stronger winds with
dominant wave period possibly dropping down to 6 to 8 seconds at
times.

Gusty offshore winds may return to the inner waters around
Thursday.

&&

.BEACHES...21/147 PM.

A abnormally high astronomical tide will continue the threat of
minor tidal overflows and minor beach erosion through the weekend.
A BEACH HAZARDS STATEMENT remains in effect through Sunday
evening. There is a 20-30 percent chance it will need to be
extended with building surf focused across west and northwest
beaches.

A building northwest swell will likely bring high surf to the
west and northwest facing beaches of the Central Coast and
Ventura County Sunday into at least Monday with a HIGH SURF
ADVISORY issued to cover this hazard. There is a 30-40 percent
chance that west facing beaches the Santa Barbara South Coast and
Los Angeles county reach High Surf Advisory criteria.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 8 AM to 6 PM PST Sunday for
      zones 53-54-352-353-356. (See LAXNPWLOX).
     High Wind Warning in effect from 6 PM Sunday to 2 PM PST
      Monday for zone 54. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Sunday evening for
      zones 87-340-346-349-350-354-362-364. (See LAXCFWLOX).
     Wind Advisory in effect from 8 AM Sunday to 2 PM PST Monday
      for zone 88. (See LAXNPWLOX).
     High Surf Advisory in effect from 10 AM Sunday to 10 PM PST
      Monday for zones 340-346-354. (See LAXCFWLOX).
     Frost Advisory in effect from 1 AM to 8 AM PST Sunday for
      zones 341-346>348-357. (See LAXNPWLOX).
     Wind Advisory in effect from 6 PM Sunday to 2 PM PST Monday
      for zones 358-359-363-547-548. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 10 AM to 10 PM PST Sunday
      for zones 645-650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 10 AM PST Sunday for
      zones 670-673. (See LAXMWWLOX).
     Gale Warning in effect from 10 AM to 10 PM PST Sunday for
      zones 670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 AM to 10 AM PST Sunday
      for zone 676. (See LAXMWWLOX).

&&

PUBLIC...MW
AVIATION...Munroe
MARINE...Munroe
BEACHES...Munroe
SYNOPSIS...MW

weather.gov/losangeles

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