High Wind in California, November 15 to 16, 2022

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
433 PM PST Tue Nov 15 2022

Updated aviation section

.SYNOPSIS...15/156 PM.

Moderate to strong Santa Ana winds will bring threats of wind
damage and wildfire through Thursday, peaking tonight through
Wednesday. Calmer and benign weather is forecast later Thursday
into the weekend. Temperatures will warm at lower elevations with
the offshore flow but remain cool across the interior. Another
strong Santa Ana wind event is possible on Saturday.

&&

.SHORT TERM (TDY-THU)...15/214 PM.

Everything is pointing to a significant Santa Ana wind event for
parts of LA/Ventura Counties tonight into Wednesday. If anything,
models have increased the chances of warning level winds
developing with strong support between 700 and 900mb and the
LAX/DAG pressure gradient near -9mb. Winds have already started
today, especially in the mountains and some of the higher valley
areas where winds up to 50 mph have occurred. These conditions
will become more widespread overnight into Wednesday morning and
even pushing far beyond the beaches over the coastal waters.
However, as is common with Santa Ana events, even big ones, most
of the LA Basin and San Gabriel Valley will experience light and
variable wind conditions. The one exception here will be the
extreme southern portion, including Long Beach and Palos Verdes
which should see some gusts into the 30s at times. There will be
some locally breezy northeast winds across SLO and Santa Barbara
Counties but mainly in the hills and mountains and much weaker
than across LA/Ventura Counties.

Offshore flow will weaken rapidly Wednesday afternoon but there
will still be enough support aloft to keep breezy winds going
through at least Wednesday night and even into Thursday morning,
especially in the mountains and favored passes and canyons. Will
likely need wind advisories overnight into Thursday for some
areas. Offshore flow continues to weaken Thursday night into
Friday but there remains enough upper support and surface gradient
to support some gusty winds, mainly in LA mountains and LA/Ventura
higher valley areas.

Temperatures will get a boost at lower elevations from the
downslope warming but because the source air mass is still quite
cold this won't be a hot Santa Ana. Temps are always tricky in
downslope events but it will likely be warmest at the coast with
highs in the mid to high 70s and slightly cooler in the valleys.
Temps will be coolest across the interior where highs will
struggle to reach the 60s. Similar to slightly warmer temps
Thursday. 3-6 degrees of cooling expected Friday for coast and
coastal valleys with an earlier sea breeze.

.LONG TERM (FRI-MON)...15/213 PM.

EPS solutions continue to trend stronger with another Santa Ana
wind event for Saturday following a dry trough passage through
the Great Basin. GFS LAX-DAG gradients are around -6mb and the
ECMWF is close to -9mb, which would potentially make this a
similar magnitude as the Wednesday wind event. Will get a better
look at it as Saturday will fall in the hi res window tomorrow,
however even today's hi res models are showing increasing winds as
early as Friday afternoon, similar to what we are seeing today.
However, the ECMWF EPS members are about 5-10 mph weaker than the
this first event tomorrow so for now the Saturday event does
appear to be slightly less intense. With the resurgence in
offshore flow and downsloping winds most coastal areas should
notice an increase in temps again back into the mid 70s, possibly
higher while it remains cooler across the interior.

Still some lingering offshore breezes Sunday but much weaker than
Saturday. The rest of the forecast period through early next week
looks uneventful with temperatures cooling slightly for
coast/valleys as the offshore flow weakens but little change
elsewhere. Looks like there should be enough offshore flow to keep
marine layer stratus away from the coast. There is some potential
for another Santa Ana event either next Tuesday or Wednesday but
there's a fair amount of variability in the EPS solutions in terms
of the track of the next upper level system so not a lot of
confidence yet either way.

&&

.AVIATION...16/0030Z.

At 23Z, the marine layer depth was around 550 feet deep at KLAX.
The top of the marine inversion was around 1050 feet with a
temperature near 16 degrees Celsius. There was another inversion
up to around 1800 feet.

High confidence in the current forecast for flight categories.
Moderate-to-high confidence in the current forecast for winds.
There is a low chance of VLIFR conditions at KPRB between 13Z and
16Z. There is a moderate-to-high (40-60 percent) chance of
moderate to strong wind shear and turbulence developing through
04Z and lingering through 16Z.

KLAX...VFR conditions are expected through the period. There is 50
percent chance of moderate to strong wind shear and turbulence
between 04Z and 09Z, reducing to 40 percent between 09Z and 16Z.

KBUR....VFR conditions are expected through the period. There is 60
percent chance of moderate to strong wind shear and turbulence
between 04Z and 16Z.

&&

.MARINE...15/109 PM.

No changes to the marine forecast in the afternoon update.

For the northern two outer waters zones (PZZ670/673), moderate
confidence in the forecast. Winds and seas are expected to remain
below Small Craft Advisory (SCA) levels thru Wed night, although
there is a 30% chance of SCA level N-NE winds late Tue night and
early Wed near the coast and the Channel Islands. There is a good
chance of NW SCA level winds Thu afternoon, then SCA winds are
likely Fri.

In the southern outer water zone (PZZ676), moderate confidence in
the forecast. Winds are seas are expected to remain below SCA
level thru this evening. SCA level NE winds are likely (50-60%
chance) late tonight thru Wed afternoon, along with steep NE wind
waves. There is a 30% chance of Gale force gusts Wed morning
south of Santa Cruz Island, especially across the eastern portion.
Conds should be below SCA levels Wed night, but NW SCA conds are
likely again Thu thru Fri.

For the Inner Waters north of Point Sal, moderate confidence in
the forecast. SCA conds are not expected through Fri, except
there is a 30% chance of SCA level NE winds very late tonight and
Wed morning.

For the Inner Waters south of Point Conception, moderate
confidence in current forecast. NE SCA level winds are likely
(50-60%) late this afternoon into this evening preceding Gale
Force winds that are expected late this evening into Wednesday,
with a 30% chance of occuring a few hours after the SCA start
time. NE winds will likely reach GALE WARNING levels late tonight
and continue through Wed afternoon across eastern portions of the
SBA Channel to Santa Cruz over much of the southern inner waters
zone (PZZ655) including out to Catalina Island. A Gale Warning
remains in effect for the inner waters south of Point Conception.

This event has the potential to be a significant and dangerous
wind event with short period, choppy waves near harbors and the
strongest winds near the mainland coast. (See the MWS for more
info). SCA conds are not expected Wed night through Fri, although
there could be local SCA level N-NE wind gusts from Ventura to
Malibu late Wed night and Thu morning.

&&

.FIRE WEATHER...15/309 PM.

Northeast winds have been strengthening through the day across Los
Angeles and Ventura Counties with widespread gusts ranging from 30 to 45
mph, with isolated gusts to 60 mph in the favored windy spots in the Los
Angeles County mountains. Winds will further strengthen this evening
into the overnight hours with widespread gusts of 40 to 60 mph likely,
strongest across the Los Angeles County mountains. Strong high pressure
building into the Great Basin will likely support the first strong Santa
Ana event of the season tonight into Wednesday focused across western
Los Angeles County into much of Ventura County. The wind-prone coastal
and valley areas will likely see peak gusts in the 40 to 60 mph range,
and the Los Angeles County mountains will likely see gusts of 55 to 75
mph. Relative humidity will likely remain above critical values through
tonight, with minimums of 15 to 25 percent. Additional drying is
expected Wednesday morning into the afternoon with minimums as low as 6
to 12 percent. Gusty and potentially damaging winds combined with very
low humidity will likely support at least 6 hours of critical fire
weather across much of Los Angeles and Ventura Counties, and as such a
Red Flag Warning will be in effect from 7am to 7pm Wednesday. Moderate
to strong upper-level support will also likely bring gusty winds of 40
to 50 mph tonight through Wednesday evening to the foothills around the
San Gabriel and Ojai Valleys which are typically protected from Santa
Ana winds. Gusts to 35 mph are also possible across the valley floors.

Elevated to brief critical fire weather conditions will be common
elsewhere, including potentially the Santa Barbara and San Luis Obispo
coastal slopes and foothills where peak wind gusts of 30 to 45 mph will
be possible. Dry conditions will linger into Thursday, but with much
lighter winds, possibly even remaining below advisory levels.

Another moderate to potentially strong Santa Ana is possible this
weekend with the potential of being similar in intensity as the current
event. Critical fire weather conditions may become more likely with this
offshore event as fuels have a chance to dry out with this first
event.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 7 PM PST this evening for zones
      53-54-88-358-359. (See LAXNPWLOX).
     High Wind Warning in effect until 7 PM PST Wednesday for
      zones 53-54-88-354-355-358-359-362-363-547. (See LAXNPWLOX).
     Wind Advisory in effect from 10 PM this evening to 7 PM PST
      Wednesday for zones 357-548. (See LAXNPWLOX).
     Red Flag Warning in effect from 7 AM to 7 PM PST Wednesday
      for zones 254-288-354-355-358-359-362-363-547. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 10 PM PST this evening
      for zones 650-655. (See LAXMWWLOX).
     Gale Warning in effect from 10 PM this evening to 3 PM PST
      Wednesday for zones 650-655. (See LAXMWWLOX).
     Small Craft Advisory in effect from 10 PM this evening to 3
      PM PST Wednesday for zone 676. (See LAXMWWLOX).

&&

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

weather.gov/losangeles

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
419 PM PST TUE NOV 15 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0150 PM     NON-TSTM WND GST 8 S AGUA DULCE          34.39N 118.34W
11/15/2022  M58 MPH          LOS ANGELES        CA   MESONET

            MESONET STATION SE678 MAGIC MTN TRUCK TRL
            (SCE).

0253 PM     NON-TSTM WND GST 8 ESE CASTAIC LAKE      34.60N 118.58W
11/15/2022  M59 MPH          LOS ANGELES        CA   MESONET

            MESONET STATION WMSC1 WARM SPRINGS RAWS.

&&

HALL