109
FXUS66 KLOX 141229
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
429 AM PST Tue Jan 14 2025

.SYNOPSIS...14/215 AM.

Moderate to strong offshore flow will remain in place through
Wednesday with a dry air mass across the region. An extended
period of critical fire weather conditions will continue across
Southland through midweek due to the combination of gusty winds,
very low humidities, and a lack of rainfall. Cold overnight
temperatures are expected in wind protected areas for the next
few mornings. A cooling trend with higher humidities is expected
beginning Thursday and lasting through the weekend.

&&

.SHORT TERM (TDY-THU)...14/304 AM.

Slightly odd upper level pattern today with a upper low well to
the SW of KLAX and a 584 dam ridge above it nosing into OR. There
is NE flow aloft over Srn CA. Fortunately the speed of the upper
flow is much less than last week. There is also much less cold air
advection. At the sfc there is about 3 mb of offshore flow from
both the E and N but the E push if forecast to increase by a
couple of mb by dawn. This is a more typical Santa Ana in that
the winds are following a diurnal pattern with wind maxima in the
mornings and mininma in later afternoon and evenings. Today`s
winds have already started to ramp up and will continue to
accelerate through mid morning. Warning level gusts have begun in
the mtns and will become more widespread and then move out into
the vlys and then the csts. The winds will be a little more
northeasterly today and the axis of strongest winds will shift to
the most typical Santa Clarita Vly to Point Mugu line. Most of the
warning level gusts will temporally subside later this afternoon.

Not much change is slated for Wednesday. High Rez mdls indicate
that the wind speeds should be slightly less that today`s
readings. The good news is that the upper support will collapse in
the afternoon and there will only be a few advisory gusts
lingering until evening. There will be another uptick in wind
speeds, but with no upper support the winds will only be in the 15
to 25 mph range.

The combination of winds, extremely low humidities and tinder dry
fuels will lead to an extremely dangerous fire weather
environment. Please see the fire weather discussion below for all
of the details.

The very cold air mass remains in place and all of the wind
sheltered inland locations will see freezing temperatures each
night. Some lows will be as low as 15 degrees. Another round of
Freeze/Frost products will be needed tonight.

The cold air mass will moderate a little each day and most max
temps will warm some each day. Most of Wednesday`s max temps will
be within a few degrees of 70 across the csts/vlys.

.LONG TERM (FRI-MON)...14/319 AM.

Dry but benign weather is on tap for Friday and the weekend. Dry
cyclonic flow will be over the state. Week offshore flow will
continue from the north but there will be onshore flow to the east
(esp in the afternoon). There is even a chance of marine layer
clouds for the coasts and lower vlys on Fri and Sat mornings.

Look for three days of cooling with Sunday`s max temps ending up a
few degrees either side of 60 across the csts and vlys. These max
temps are 4 to 8 locally 10 degrees below normal.

Not the greatest confidence in the Monday forecast. Some solutions
do favor a another moderate offshore event, but more members
indicate just a weak event with a little bit of warming.

&&

.AVIATION...14/1213Z.

At 12Z at KLAX, there was no marine layer nor inversion.

Expecting VFR conditions for all TAF sites thru the period, with
a 10-20% chance of MVFR conds in smoke for the Los Angeles County
coastal terminals this morning.

Gusty N to NE winds will affect much of the forecast area,
especially in VTU/L.A.Counties. There will be areas of LLWS, and
moderate to locally strong UDDF and turbulence, especially near
the foothills and mtns. Winds may be erratic at times, changing
quickly between gusty and light.

KLAX...High confidence in VFR conds thru the period. However,
there is a 10-20% chance of 4-5SM FU and/or bkn025 smoke layer
thru 20Z. There is a 30% chance of an east wind component
reaching 8-10 kt thru 19Z.

KBUR...High confidence in VFR conds thru the pd. Moderate
confidence in winds. Maximum wind gusts may be off +/- 10 kts and
wind group changes may be off +/- 3 hours. LLWS is likely,
especially thru 18Z. Moderate to locally strong turbulence and
UDDF will also affect the terminal at times during the period.

&&

.MARINE...14/428 AM.

In the Outer Waters, Small Craft Advisory (SCA) level E-NE winds
will persist in the southern zone (PZZ676) thru Wed afternoon.
Local Gale force gusts are possible (20-30% chance) this morning
and again late tonight/early Wed in PZZ676. Otherwise, winds and
seas will be below SCA levels thru Sat night. There is a 30-40%
chance of SCA level NW winds Fri night/Sat. mainly southern zones.

In the inner waters N of Pt. Sal, except for a 20% chance of SCA
level NE winds nearshore during the morning hours today and Wed,
SCA level conds are not expected thru Sat night.

In the Santa Barbara Channel, Gale force winds are expected much
of the time thru early Wed afternoon from Ventura to eastern
Santa Cruz Island southward. Winds may drop down to  SCA levels
at times during this period, especially this evening. SCA level NE
winds may continue into Wed night, then benign conds are expected
Wed night thru Sat night. Elsewhere, there is a 20% chance of SCA
level E winds this morning and again late tonight/Wed morning.

In the southern inner waters. Gale force winds are expected from
Malibu to Point Mugu and out to Anacapa Island much of the time
thru Wed afternoon. Winds may drop below Gale force at times,
especially this evening. Then, SCA level NE winds will likely
continue into Wed evening. Elsewhere, SCA level NE winds are
likely at times thru Wed afternoon. This is especially likely
(80% chance) thru the San Pedro Channel out to Avalon and Two
Harbors on Catalina Island this morning, and again late tonight
and Wed morning. There is a 40% chance of Gale Force winds in
this area. Benign conds are then expected Wed night thru Fri.

&&

.FIRE WEATHER...13/432 PM.

...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN
EFFECT 4 AM TUESDAY UNTIL NOON WEDNESDAY DUE TO DAMAGING
NORTHEAST TO EAST WINDS AND LOW HUMIDITIES FOR THE FOLLOWING
AREAS: WESTERN SAN GABRIEL MOUNTAINS/ I5 CORRIDOR/ SOUTHERN
VENTURA COUNTY MOUNTAINS/ SANTA SUSANA MOUNTAINS/ VENTURA VALLEYS
(MAINLY NEAR SIMI VALLEY/MOORPARK/ SANTA PAULA/SOUTH MOUNTAIN)/
WESTERN SANTA MONICAS/ WESTERN SAN FERNANDO VALLEY (MAINLY
HIGHWAYS 118/210 CORRIDORS FROM PORTER RANCH TO SAN FERNANDO)/
CALABASAS/AGOURA HILLS/ VENTURA COUNTY COASTAL PLAIN--THIS WILL
BE A TIME PERIOD OF LOCALLY DAMAGING WINDS WITH EXTREMELY
CRITICAL FIRE WEATHER CONDITIONS...

...RED FLAG WARNINGS IN EFFECT FOR MUCH OF LOS ANGELES AND
VENTURA COUNTIES THROUGH 6 PM WEDNESDAY DUE TO GUSTY NORTHEAST TO
EAST WINDS AND LOW HUMIDITIES...

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING TO
NOON PST WEDNESDAY FOR GUSTY EAST WINDS AND LOW HUMIDITY FOR THE
MOUNTAINS OF SANTA BARBARA AND SAN LUIS OBISPO COUNTIES AS WELL AS
SANTA YNEZ MOUNTAINS EASTERN RANGE, LAKE CASITAS, AND OJAI
VALLEY...

***THIS IS A PARTICULARLY DANGEROUS SITUATION (PDS) FOR PORTIONS
  OF LOS ANGELES AND VENTURA COUNTIES!***

.DISCUSSION...
.A long duration Red Flag Warning remains in effect across much
of Los Angeles and Ventura counties through 6 PM Wednesday, expanding
into the mountains of San Luis Obispo and Santa Barbara counties
by tonight. THERE WILL LIKELY BE DAMAGING WINDS GUSTING BETWEEN
55 AND 70 MPH ACROSS PORTIONS OF THE RED FLAG WARNING AREA FROM
EARLY TUESDAY MORNING THROUGH WEDNESDAY MORNING, LEADING TO THE
PDS RED FLAG WARNING UPGRADE. AREAS IN THE RED FLAG WARNING
(ESPECIALLY DURING THE PDS TIME FRAME) WILL HAVE A HIGH RISK FOR
LARGE FIRES WITH VERY RAPID FIRE SPREAD, EXTREME FIRE BEHAVIOR,
AND LONG RANGE SPOTTING. WHILE DANGEROUS PDS RED FLAG FIRE WEATHER
CONDITIONS ARE LIKELY WITH THIS EVENT EARLY TUESDAY MORNING INTO
WEDNESDAY MORNING, THIS WIND EVENT IS NOT EXPECTED TO BE AS STRONG
AND DESTRUCTIVE AS LAST WEEK`S WINDSTORM. Due to the more
easterly component of the wind, much of Ventura County will likely
have stronger winds than the offshore wind events this past week.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Freeze Warning remains in effect until 9 AM PST this morning
      for zones 38-343-344-346>348-357-381>383. (See LAXNPWLOX).
     High Wind Warning remains in effect until noon PST Wednesday
      for zones 88-354-355-358-362-369-371-372-374>376-378>380. (See LAXNPWLOX).
     Frost Advisory remains in effect until 9 AM PST this morning
      for zones 340-341. (See LAXNPWLOX).
     Wind Advisory in effect until 6 PM PST Wednesday for zones
      354-355-358-369-372-374>376-378-379. (See LAXNPWLOX).
     Wind Advisory remains in effect until noon PST Wednesday for
      zones 370-373-377. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PST Wednesday for zones
      288-354-355-358-362-369>376-378>380-548. (See LAXRFWLOX).
     Red Flag Warning in effect until noon PST Wednesday for zones
      345-352-353-356-357. (See LAXRFWLOX).
PZ...Gale Warning in effect until 3 PM PST Wednesday for zones
      650-655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PST Wednesday for
      zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB/Lewis
FIRE...Gomberg/Cohen
SYNOPSIS...MW

weather.gov/losangeles

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