751 
FXUS66 KLOX 132221
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA 
221 PM PST Fri Jan 13 2023

.SYNOPSIS...13/208 PM.

A series of storms will bring periods of rain and mountain snow to
the area through Monday. High surf will continue across the 
beaches through at least Saturday evening and again next week.

&&

.SHORT TERM (TDY-MON)...13/206 PM.

A somewhat complicated pattern over the next 3-4 days as a series
of storms move through the area. A weak system moved through
earlier today and brought light rain to western SLO and Santa 
Barbara Counties. Models at one time indicated that this area of 
showers would progress through the remainder of the area overnight
tonight but more recent HRRR runs have scaled back on this. 
Radars do show some light showers moving into Central Santa 
Barbara County this afternoon but it's looking less likely that it
will survive much farther east as the core of the storm lifts 
northeast. At best probably just some sprinkles or very light
showers tonight.

The next system still on tap for Saturday and Saturday night and
looks more or less on track in terms of timing and amounts.
Lighter warm-frontal showers expected to develop at some point in
the morning or early afternoon as south to southwest flow
increases. In these cases showers often develop sooner than models
expect, but in any case the primary focus will be on the main
frontal band which is expected to come through between late 
afternoon for SLO and Santa Barbara Counties and evening for 
LA/Ventura Counties. It's during this period when rain rates will 
be at their highest. There have been a few hi res models today 
that have shown one hour rates as high as 0.80"/hr, though most of
them have been closer to a half inch and that seems to be the 
most likely scenario. With these rates impacts will be slightly 
greater than what would normally occur with a storm of this 
magnitude since the ground is still fairly saturated from previous
rain, but still just on the minor side, including small mud 
slides in the foothills and mountains, and typical minor road 
flooding. Amounts still projected to be around an inch for 
coast/valleys and 1.5-3 in the mountains. Snow levels will be at 
or above 7000' for most of this event so accumulations will be 
confined to higher elevations. For this reason have opted to go 
with a winter weather advisory rather than a winter storm warning 
as impacts for most of the mountain areas will be at elevations 
with very few people. The mountain resorts on the LA/San 
Bernardino County should do well with accumulations, especially at
8000' and above where a foot or more could fall. Rain and snow 
expected to taper off Saturday night as the flow quickly shifts to
northwest. During this short period into Sunday morning snow 
levels will fall to around 5000' as the colder air moves in, 
however accumulations down to that level are expected to be 
minimal at best.

There will be typical gusty southerly winds ahead of the front
through Saturday night. The winter weather advisory will cover the
winds in the LA/Ventura mountains. The Antelope Valley and
interior SLO County will also see advisory level winds at times. 

A break in the weather most of Sunday until later in the afternoon
and evening when the next storm arrives. This one has less 
moisture to work with but is a little colder and has the potential
for convection at the end of it. Ensembles have been consistently
producing about half the amount of rainfall, though if
thunderstorms do develop (best chances later Monday into Monday
night) rainfall totals could end being similar in those locations.
The colder storm will bring accumulating snow to lower elevations
(mainly 5000' and higher), but overall snow amounts will be lower
than the with the Saturday system. There's a 10-20% chance that
lingering moisture and northwest flow following the system could
cause some light snow accumulations down to around 4000' late
Monday night into early Tuesday.

.LONG TERM (TUE-FRI)...13/221 PM.

Models now trending dryer for Tuesday as the Monday system exits
to the east and northwest flow takes over. Most ensemble solutions
show a dry pattern the rest of the week with periods of gusty
north to northwest winds. Then shifting to Santa Ana's later in
the week into next weekend.

&&

.AVIATION...13/1755Z.

At 17Z at KLAX, there was a weak inversion at 400 ft with the top
at 700 ft and a temp of 16 deg C.

Moderate confidence overall in the 18Z TAFs. A mix of MVFR and 
VFR cigs/vsbys will prevail at all the coast and vly airfields 
thru the period. Changes between flight cats will vary as well and
any changes may be off +/- an hour or two. For KWJF and KPMD,
there is generally hi confidence in VFR TAFs thru the fcst 
period.

KLAX...Moderate confidence overall in the 18Z TAF. Conds will be
VFR for most of the fcst pd then MVFR conds are expected aft about
17Z Sat. The change in flight cats may be off +/- an hour or two.

KBUR...Moderate confidence overall in the 18Z TAF. Conds will be
VFR for most of the fcst pd then MVFR vsbys are expected aft 
about 17Z Sat, with a 30%-40% chance of MVFR cigs as well. The 
change in flight cats may be off +/- an hour or two.

&&

.MARINE...13/116 PM.

For the Outer Waters, moderate to high confidence in the current 
forecast. Small Craft Advisory (SCA) conds are expected at least 
through late Sunday night due to SCA level seas and/or winds as 
more Pacific storms move into the area. There will then be a 
40%-50% chance of SCA levels winds and seas Monday through 
Wednesday. There is also a 40%-50% chance of gale force gusts for 
the northern zone (PZZ670) Sunday night and Monday. Peak seas 
during the forecast period are expected Monday night with seas up 
to 15-20 feet. 

For the Inner Waters north of Point Sal, moderate to high 
confidence in the current forecast. SCA conds are expected at 
least through late Sunday night due to SCA level seas and/or 
winds. There will then be a 40%-50% chance of SCA levels winds 
and/or seas Monday through Wednesday. Peak seas during the 
forecast period are expected Monday night with seas up to 16 to 19
feet possible. Large, breaking waves will be possible at harbor 
entrances through Saturday, and again Monday afternoon through 
Tuesday.

For the Inner Waters south of Point Conception, moderate to high
confidence in the current forecast. SCA conds are expected at 
least through late Sunday night due to SCA level seas and/or 
winds. There will then be a 40%-50% chance of SCA levels winds 
and/or seas Monday through Wednesday. Peak seas during the 
forecast period are expected Monday night with seas up to 9 to 12
feet possible.

&&

.BEACHES...13/128 PM.

A couple of storm system moving into the area will bring a 15-18 
foot west swell with a 17-19 second period into the coastal waters
through this evening then slowly subside through Saturday night. 
Therefore, a HIGH SURF ADVISORY is in effect for San Luis Obispo, 
Santa Barbara, and LA County Beaches through Saturday evening. A 
HIGH SURF WARNING is in effect for Ventura County Beaches due to 
the westerly component of this long period, large swell. There is
less confidence in the LA County beaches reaching 15 feet and 
Central Coast beaches reaching 20 feet, so Advisories will 
continue. With another storm system coming in Monday into Tuesday,
there is a likelihood that the advisories/warnings will be needed
again by early next week.

Warning level surf can cause beach erosion along with a threat of
minor coastal flooding at the time of high tides, and damage to 
coastal structures and piers.

For more details about the High Surf Advisories and Warnings, 
please refer to the Coastal Flood Advisory product (LAXCFWLOX).

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Weather Advisory in effect from noon Saturday to 3 AM
      PST Tuesday for zones 53-54. (See LAXWSWLOX).
     Wind Advisory in effect from noon Saturday to midnight PST
      Saturday night for zone 59. (See LAXNPWLOX).
     High Surf Advisory in effect until 10 PM PST Sunday for zones
      87-340-346-362-364. (See LAXCFWLOX).
     Wind Advisory in effect from noon to 9 PM PST Saturday for
      zones 345-353. (See LAXNPWLOX).
     High Wind Watch in effect from Saturday afternoon through
      Saturday evening for zones 345-353. (See LAXNPWLOX).
     High Surf Advisory in effect until 10 PM PST Saturday for
      zones 349-350. (See LAXCFWLOX).
     High Surf Warning in effect until 3 PM PST Saturday for zone
      354. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Monday for
      zones 645-650-655-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PST Sunday for zone
      670. (See LAXMWWLOX).

&&

$$

PUBLIC...MW
AVIATION...Sirard
MARINE...Sirard
BEACHES...Sirard
SYNOPSIS...MW

weather.gov/losangeles

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