High Wind in California, January 7 to 10, 2025

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
320 AM PST Tue Jan 7 2025

.SYNOPSIS...07/312 AM.

Widespread damaging north to northeast winds and extreme fire
weather conditions will develop today through Wednesday. Winds
will peak this evening through Wednesday morning. Downed trees,
hazardous driving conditions, increased traffic, power outages,
and airport delays are to be expected across Los Angeles and
Ventura Counties. Any wildfires that start may spread rapidly with
extreme fire behavior.

&&

.SHORT TERM (TDY-THU)...07/312 AM.

***STRONG AND DAMAGING WINDS WITH DANGEROUS FIRE WEATHER
 CONDITIONS FOR PORTIONS OF VENTURA AND LOS ANGELES COUNTIES TODAY
 THROUGH THURSDAY***

Very little change to the forecast. Everything is on track for a
major wind event. Currently the base of large pos tilt trof is
over the eastern half of SoCal. To the west of the trof axis a
very fast river of air moving from the NNE to SSW. This wind
energy will move directly overhead of SBA/VTA/LA counties later
this morning along with a very large amount of cold air advection
which will serve to drive the higher altitude winds down to the
sfc.

Current offshore gradients are 6 mb from the north, but on 1.5 mb
from the east. And this and the position of the upper flow means
that this wind event will start out as a more northerly one. The
offshore push from the east will increase through the day will the
north push will be pretty steady at the same time the upper flow
will tilt to the NE and the wind event will slowly transition to
a more NE one. But not quite as far NE as a typical Santa Ana.

High wind warnings will go into effect today for much of the LA
and VTA county area. The mountains will see gusts from 65 to 80
mph with local gusts near 100 mph. Cst/Vly areas will see gusts
between 60 and 70 mph. For exact locations and timing of all of
the wind products please see the product LAXNPWLOX.

One item that must be highlighted is the danger of a breaking
mountain wave. Later today 100 mph winds are going to be slamming
into the tops of the San Gabriel Mtns. This interaction will very
likely cause many standing mountain waves (if there is enough
moisture in the air these waves will show themselves as lenticular
cloud which a smooth and nearly stationary) Every once in a while
one of these waves will break and send its energy to the sfc where
it will likely produce a local pocket of damaging 80 mph to 100
mph winds.

These strong winds will likely continue all the way through
Wednesday afternoon since the upper support is very slow moving.
The peak of the event looks to be from 1000 pm tonight to 1000 am
Wednesday. Since the winds will be shifting from a northerly
direction to a northeasterly direction areas will see the winds
increase and decrease at different times.

One small oddity to add to today's mix is the threat of mtn snow
on the north side and peaks of the San Gabriel mtns as a small
disturbance moving out of NV will move into the mtns and be
enhanced with upslope flow. Look for clouds and snow with local 3
inch accumulations above 8000 ft.

Current mdls show a substantial drop off in winds for Thursday and
advisories may only be needed in the mtns.

Elsewhere across San Luis Obispo and western Santa Barbara
counties, the offshore winds will be much weaker. However, there
will be locally gusty northeast winds through and below passes and
canyons.

Residents across Southern California are urged to remain vigilant
and monitor the latest forecasts. There is high confidence in
strong offshore winds with the potential to be the strongest wind
event of the season, especially for the Southland valleys. Trees,
large tree branches, and power lines may be downed by the wind
next week. Residents living the near the foothills and mountains
are advised to review the Ready,Set,Go! fire plan. Most residents
should be in the Set stage and being prepared to go in the event
of the fire evacuation.

Max temperatures will be interesting with this event. There will
be so much cold air advection today that it will totally
overwhelm the usual compressional heating that occurs with Santa
Ana winds. Max temps Tuesday will cool 5 to 10 degrees across the
board. On Wednesday/Thursday, there will be much less cold air
advection and max temps will rise by about 4 to 8 degrees on
Wednesday and a couple more degrees on Thursday for interior
areas.

Overnight lows on tonight and Wednesday night will be very cold
in wind sheltered locations with clear skies, dry air and a cool
airmass.

.LONG TERM (FRI-MON)...07/142 AM.

Both the EC and GFS deterministic mdls as well as their ensemble
means are in good agreement through the xtnd period.

Friday will be the last day of the wind event. At one time it
looked like there would only be sub advisory winds but now the NAM
is showing 35 to 40 mph 850 mb wind support and 4 to 5 of offshore
flow from the east and north. This should translate into one more
morning of advisory level wind gusts through the Santa Ana wind
corridor. Max temps will remain 4 to 8 degrees above normal with
cst/vly temps in the upper 60s and 70s.

The upper flow switches to NW on Friday as a little impulse ripple
out of PACNW. This will end the wind event. The W/E gradient will
be near neutral and the N/S gradient will only be weakly offshore.
There may even be some morning low clouds. Lower hgts and weaker
offshore or actual onshore flow will bring 3 to 6 degrees of
cooling to the whole area.

Offshore flow builds back in both Sunday and Monday. Unlike this
week these offshore gradients will not be bolstered by much of any
upper support and only low end advisory gusts are possible. Hgts
lower and cool air will be swept in from the interior and this
will bring some cooling each day to most areas exp the csts where
the offshore flow may bring a few degrees of warming.

&&

.AVIATION...07/0645Z.

At 0510Z at KLAX, there was no marine layer. There was a sfc based
inversion with a top 3200 feet with a temperature of 15 C.

Good confidence in VFR conds at all sites xcp KPRB.

Moderate confidence in wind forecasts. Aviators need to be aware
that the area will be affected by a very strong wind event
starting around 12Z today and lasting into Wednesday. Wind shift
timing could be off by +/- 3 hours; wind direction could be off
by +/- 30 degrees and wind speeds and gusts by as much as 10 kt.

Mdt turbc is likely at times and svr turbc is possible. The
highest chc of turbc will be over and near to the hier trrn. Mdt
to locally stg LLWS is possible at LA coast and vly sites.

KLAX...High confidence in VFR conds through the period. Lower
confidence in wind fcst. Wind shift timing could be off by +/- 3
hours; wind direction could be off by +/- 30 degrees and wind
speeds and gusts by as much as 10 kt. Winds may become gusty and
erratic at times after 13Z varying from 350 to 070 degrees. LLWS
will be possible at any time aft 13Z. There is 20 percent chc of a
15 kt east wind component 14Z-21Z. Mdt turbc is possible on
descent.

KBUR...High confidence in VFR conds through the period. Lower
confidence in wind fcst. Wind shift timing could be off by +/- 3
hours; wind direction could be off by +/- 30 degrees and wind
speeds and gusts by as much as 10 kt. MDT LLWS is possible after
15Z. MOD-ISOLD SVR turbc is possible on climb and esp descent.

&&

.MARINE...07/304 AM.

Another exceptionally strong north-northeasterly Santa Ana wind
event is set to impact portions of our coastal waters today and
Wednesday. Mariners should expect DANGEROUS wind and sea
conditions across all of waters off the coast of Los Angeles and
Orange Counties. This expansive area includes all of PZZ655,
much of PZZ676, and the eastern/nearshore portions of the Santa
Barbara Channel (Ventura Harbor and Port Hueneme through Point
Mugu), including the waters around the Channel Islands and
Catalina Island.

***Details***

For Inner waters from Point Mugu to San Mateo Pt. CA including
Santa Catalina and Anacapa Islands (PZZ655), expect GALE Force N
to NE winds - 20 to 30 kt with gusts to 45 kt during the day
today, increasing to STORM Force level winds this afternoon
through Wednesday afternoon/eve with gusts up to 50 kts. Combined
seas will peak around 6 to 9 feet.

For Outer waters from Santa Cruz Island to San Clemente Island to
60 NM offshore including San Nicolas and Santa Barbara Islands
(PZZ676), expect GALE force N to NE winds - 20 to 30 kts with
gusts to 45 kt this morning through Wednesday afternoon/eve.

Please take this situation seriously, mariners should remain in
port, alter course, and/or secure the vessels as these
exceptionally dangerous sea conditions could capsize or damage
vessels of ALL sizes.

&&

.FIRE WEATHER...06/440 PM.

***PARTICULARLY DANGEROUS SITUATION RED FLAG WARNING FOR PORTIONS OF
LOS ANGELES AND EASTERN VENTURA COUNTIES NOON TUESDAY UNTIL 4 PM
WEDNESDAY***

A very strong, widespread, and destructive north to northeast
windstorm will bring Extremely Critical fire weather conditions to
many areas of Los Angeles and eastern Ventura counties Tuesday
afternoon into early Wednesday afternoon. This is a PARTICULARLY
DANGEROUS SITUATION (PDS) Red Flag Warning event in many areas,
with the combination of very strong upper level wind support,
tightening offshore pressure gradients (LAX-Daggett peaking at
-7 to -8 mb), and moderate cold air advection. The strongest winds
with this event are expected to be Tuesday afternoon into early
Wednesday afternoon when widespread damaging wind gusts of 50 to
80 mph are likely. The San Gabriel mountains, Santa Susana
mountains, and foothills of the San Gabriel/San Fernando Valleys
will likely see areas of destructive wind gusts between 80 and
100 mph! Due to the very strong upper level wind support and high
risk for strong mountain wave activity, typical wind sheltered
areas such as portions of the LA basin and San Gabriel Valley.
The strong winds will likely result in widespread downed
trees/powerlines, as well as widespread power outages. THIS WILL
LIKELY BE THE MOST DESTRUCTIVE WINDSTORM SEEN SINCE 2011
WINDSTORM THAT DID EXTENSIVE DAMAGE TO PASADENA AND NEARBY
FOOTHILLS OF THE SAN GABRIEL VALLEY. ANY COMMUNITIES ALONG
HIGHWAY 118 AND 210 CORRIDORS WILL BE AT HIGHEST RISK FOR
COMPARABLE WIND DAMAGE. Humidity levels are also expected to
lower to between 10 and 15 percent in many areas by Tuesday
afternoon/evening, potentially lowering into single digits in
some areas by late Tuesday night into Wednesday.

The offshore winds are now expected to arrive early Tuesday
morning, resulting in the Red Flag Warning area being moved up to
4 am Tuesday in many areas. AREAS IN A RED FLAG WARNING
(ESPECIALLY DURING THE PDS TIME FRAME) WILL HAVE INCREASED RISK
FOR LARGE FIRES WITH VERY RAPID FIRE SPREAD, EXTREME FIRE
BEHAVIOR, AND LONG RANGE SPOTTING. While the longer duration of
strong winds and Red Flag conditions is expected to be focused
across Los Angeles and Ventura counties, there is now expected to
be a shorter duration of Red Flag conditions across the mountains
of Santa Barbara county Tuesday into Wednesday. Long duration Red
Flag Warnings are in effect for much of Los Angeles and Ventura
counties Tuesday through Thursday, with Fire Weather Watches in
effect Thursday night into Friday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning remains in effect from 4 PM this afternoon
      to 6 PM PST Wednesday for zones 87-366>368. (See LAXNPWLOX).
     Coastal Flood Advisory in effect from 1 AM to 9 AM PST
      Wednesday for zone 87. (See LAXCFWLOX).
     High Wind Warning remains in effect from 10 AM this morning
      to 6 PM PST Wednesday for zones
      88-358-362-369>374-376>378-548. (See LAXNPWLOX).
     High Surf Advisory in effect until 9 PM PST this evening for
      zones 340-346-354. (See LAXCFWLOX).
     Wind Advisory now in effect until 6 PM PST Wednesday for
      zones 350-352-353. (See LAXNPWLOX).
     Wind Advisory remains in effect from 8 AM this morning to 6
      PM PST Wednesday for zones 354>357. (See LAXNPWLOX).
     High Wind Warning remains in effect until 6 PM PST Wednesday
      for zones 375-379-380. (See LAXNPWLOX).
     Wind Advisory in effect until 10 AM PST this morning for
      zones 376>378. (See LAXNPWLOX).
     Wind Advisory remains in effect from 10 AM this morning to 6
      PM PST Wednesday for zones 381-382. (See LAXNPWLOX).
     Wind Advisory remains in effect from 10 AM this morning to 2
      PM PST Wednesday for zone 383. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PST Thursday for zones
      288-358-362-369>376-378>380-548. (See LAXRFWLOX).
     Fire Weather Watch in effect from Thursday evening through
      Friday afternoon for zones 288-358-362-369>376-378>380-548. (See LAXRFWLOX).
     Red Flag Warning in effect until 6 PM PST Wednesday for zones
      352-353. (See LAXRFWLOX).
     Red Flag Warning in effect from 10 AM this morning to 6 PM
      PST Thursday for zones 354-355-377. (See LAXRFWLOX).
     Red Flag Warning in effect from noon today to 4 PM PST
      Wednesday for zones 366-368. (See LAXRFWLOX).
     Red Flag Warning in effect from 4 PM this afternoon to 6 PM
      PST Wednesday for zone 367. (See LAXRFWLOX).
     Red Flag Warning in effect from 10 AM this morning to 6 PM
      PST Wednesday for zones 381>383. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Wednesday for
      zones 645-670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 6 PM this evening to 3 AM
      PST Wednesday for zone 650. (See LAXMWWLOX).
     Gale Watch in effect from late tonight through Wednesday
      morning for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 6 PM PST this evening for zone
      655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 6 AM PST early this
      morning for zone 676. (See LAXMWWLOX).
     Gale Warning in effect until 6 PM PST Wednesday for zone 676. (See LAXMWWLOX).

&&

PUBLIC...Rorke
AVIATION...Rorke
MARINE...Lund/Schoenfeld
FIRE...Gomberg
SYNOPSIS...Schoenfeld

weather.gov/losangeles

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