026
FXUS66 KLOX 190501
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
901 PM PST Sat Jan 18 2025

.SYNOPSIS...18/746 PM.

Offshore flow will return Sunday, with local northeast breezes,
less morning low clouds, and a few degrees of warming. Mostly
clear and locally breezy conditions are expected Sun night into
early Monday, then Santa Ana winds will increase during the day. A
moderate to strong Santa Ana wind event will likely affect
Ventura and Los Angeles Counties Monday night and Tuesday, with
weaker offshore flow continuing for much of next week.
Temperatures will be below normal Monday and Tuesday, with a
warming trend later next week. Humidity will be low to very low
most of next week. Frost or freezing temperatures are possible in
wind sheltered areas each night Monday through Thursday.

&&

.SHORT TERM (SAT-TUE)...18/901 PM.

***HIGH WIND WATCHES IN EFFECT LATE MONDAY AFTERNOON THROUGH
TUESDAY MORNING FOR MOST OF VENTURA COUNTY AND PORTIONS OF LOS
ANGELES COUNTY DUE TO A HIGH RISK OF WIDESPREAD DAMAGING WINDS
AND DANGEROUS FIRE WEATHER CONDITIONS***

Quiet weather will continue through Sunday night. Current satellite
imagery showing low clouds and fog returning across the Central
Coast this evening, Overnight into Sunday morning, expecting low
clouds to expand into the coastal areas of LA/Ventura counties.
Temperatures on Sunday will remain near seasonable normals.

Confidence continues to increase towards a Strong Santa Ana Wind
Event (80 percent chance) peaking in strength Monday evening
through Tuesday morning. There is an 80 percent chance of
widespread DAMAGING wind gusts of 60-80 mph in Santa Ana wind
prone mountains/foothills of LA/Ventura counties, with the potential
for isolated gusts in the 80-100 mph range across the most favored
mountain areas which for now appears to the San Gabriel mountains,
Santa Susana mountains, southern Ventura mountains near the Highway
126 corridor, and the western Santa Monicas. For wind prone
coasts and valleys, looking for peak gusts of 50-70 mph, THERE
IS NOW AN INCREASED RISK FOR A WIDESPREAD DAMAGING WIND EVENT WITH
DANGEROUS HIGH END RED FLAG FIRE WEATHER CONDITIONS. NEW OR EXISTING
FIRE IGNITIONS WILL HAVE A HIGH RISK FOR VERY RAPID FIRE SPREAD AND
EXTREME FIRE BEHAVIOR WITH LONG RANGE SPOTTING.

A very strong 1045-1050 mb surface high pressure system will rapidly
build into the Central Rockies and likely support strong offshore
gradients (-8 to -10 mb by early Tuesday morning from Los Angeles
International Airport to Dagget), very strong cold air advection, and
strong upper level wind support (850 mb wind in the 55-70 knot range,
and 700 mb winds in the 45-60 knot range). Historically, this pattern
has supported widespread damaging winds even into some coastal areas
(most notably western Malibu to the Ventura county coastal plain and
adjacent foothills) and our high resolution guidance is already supporting
this potential. There is also increasing potential for mountain wave
wind activity, which could support locally higher gusts than advertised,
especially for foothill and elevated valley communities near the Highways
118 and 210 corridors extending from Simi Valley/Moorpark eastward into the
northern San Fernando Valley, and the foothills of the San Gabriel Valley.
Due to the strong upper level wind support, even typical wind sheltered
areas of the LA Basin and the San Gabriel Valley floor could see some
gusty winds at times (mostly in the 30-50 mph range).
Given our increasing confidence in widespread damaging winds, a High
Wind Watch (see NPWLOX for details) was issued for much of Ventura/LA
counties. In evening update, will be adding the eastern San Fernando Valley
and San Gabriel Valley zones to the High Wind Watch, with special
emphasis on the northern portions of these zones near the Highway
210 corridor. In addition to the significant threat for damaging
winds, dangerous high end Red Flag Warning fire weather conditions
are also likely during this time (see our Fire Weather products
(RFWLOX) for details). See fire discussion below for more details.

.LONG TERM (WED-SAT)...18/233 PM.

Weak to moderate offshore winds will likely bring continued
significant fire weather concerns focused across Los Angeles and
Ventura Counties Wednesday through Friday. After a coolish start
to the week, a building ridge aloft and less in the way of cold
air advection will allow temperatures to warm well into the 70s
for many coastal and valley areas.

Low forecast confidence next weekend with a 20-30 percent chance
of fairly widespread and mainly light rain and mountain snow with
the potential for low snow levels. Although there is a 10 percent
chance of a thunderstorm should the associated trough deepen
enough to pass near our region, which may increase the threat for
localized heavier rainfall. There is also a 30-40 percent chance
that the storm passes far enough to the east for no rain across
most of the region. Either way a cool down is likely next weekend
with breezy winds focused across the interior.

&&

.AVIATION...19/0009Z.

At 00Z at KLAX, the marine layer was 3000 feet deep and the
inversion was 4400 ft deep with a temp of 10 C.

High confidence in desert TAFs, moderate confidence all other TAFS.
Timing of flight cat changes may be off +/- 2 hours with minimum
flight cats off by +/- 1.

There is a 30% chance of no cigs at KSBP, and if there is, 40%
chance of VLIFR-IFR conds 05Z-18Z Sun. There is a 25% chance of
IFR conds at KSBA 12Z-19Z. For KBUR and KVNY, there is a 20%
chance of MVFR conds between 12Z-17Z Sun.

KLAX...Moderate confidence in TAF. Timing of flight cat changes
may be off by up to +/- 2 hours. There is a 20% chance of
BKN/OVC0005-010 conds from 08Z to 18Z Sun. High confidence that
any east wind component remains below 8 kt thru the fcst pd.

KBUR...Moderate to high confidence in TAF. There is a 20% chance
of ~BKN/OVC015-025 12Z-17Z Sun.

&&

.MARINE...18/748 PM.

For the Outer Waters, Small Craft Advisory (SCA) level winds are
likely (70% chance) Sunday afternoon/eve thru Monday morning.
These conditions will be favored from Point Conception to San
Nicolas Island which includes the waters around and to the west of
the Channel Islands (PZZ676/673). There is a 40-50% chance of
GALE FORCE level NE winds for the waters around and to the south
of the Channel Islands (PZZ676) late Monday night thru Tuesday
morning. Otherwise, sub-advisory conds are expected thru Thursday
night.

For the Inner Waters North of Pt Sal (PZZ645), there is a 30%
chance of SCA level wind gusts Sunday afternoon/eve just offshore
of Port San Luis. Otherwise, sub-advisory conds are expected thru
late in the week.

For the Inner Waters South of Point Conception, there is a 30%
chance of SCA level wind gusts for far western portions of the
Santa Barbara Channel Sunday afternoon into late night. From
Ventura to Santa Monica and out past the Channel Islands, there is
a 60-70% chance of GALE FORCE E/NE wind gusts late Monday
afternoon through Tuesday morning. For Port Hueneme to Malibu,
there is a 20-30% chance of STORM FORCE wind gusts Monday night
into Tuesday morning. From the Orange County shores through the
San Pedro Channel, there is a 40-50% chance of GALE FORCE wind
gusts Monday evening through Tuesday morning, with a 60-70%
potential of 25-30 kt winds reaching Avalon Harbor. Steep, choppy
seas of 5 to 8 feet will be possible during this time frame.

&&

.FIRE WEATHER...18/250 PM.

Starting Monday afternoon and continuing through at least
Thursday, offshore flow and very low humidities will prevail over
the forecast area. It looks like there is the potential for wind
gusts up to 60 to 80 mph could affect the L.A. and eastern Ventura
County mountains Monday night and Tuesday morning, with gusts 55
to 65 mph possible at many valley and coastal areas of these two
counties. Combined with humidities lowering significantly to the
single digits and teens, a Red Flag Warning has been issued for
much of Ventura and Los Angeles Counties from late Monday morning
through Tuesday evening.

Gusty offshore winds and very low humidities will continue later
Tuesday night through Thursday in these same areas. The strongest
winds during this period are expected to be Wednesday night into
Thursday morning with gusts in the 40 to 55 mph range. Due to the
potential for continue Red Flag conditions, a Fire Weather watch
has also been issued for most of these areas from late Tuesday
evening through Thursday evening.

In addition, there is the potential for east to southeast wind
gusts of 20 to 35 mph to occur over interior Santa Barbara and San
Luis Obispo Counties at times next week, with a 20 percent chance
of Red Flag conditions.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Watch in effect from Monday afternoon through
      Tuesday morning for zones
      88-354-355-358-362-369-371-372-374>380. (See LAXNPWLOX).
     Red Flag Warning in effect from 10 AM Monday to 10 PM PST
      Tuesday for zones 288-354-355-358-362-369>380-548. (See LAXRFWLOX).
     Fire Weather Watch in effect from Tuesday evening through
      Thursday evening for zones 288-354-355-358-362-369>380. (See LAXRFWLOX).
PZ...Gale Watch in effect from Monday afternoon through Tuesday
      morning for zones 650-655-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM Sunday to 9 AM PST
      Monday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Munroe
AVIATION...Lund/Gomberg
MARINE...Lund/Smith
FIRE...Sirard
SYNOPSIS...DB/RM/CS

weather.gov/losangeles

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