Wind Advisory 15, NWS Los Angeles, CA

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
102 AM PST Tue Feb 4 2025

.SYNOPSIS...03/113 PM.

Generally dry conditions are mild into Tuesday, with areas of
dense fog. The first storm system will bring widespread light to
moderate rain and gusty winds Tuesday and Wednesday, with the
highest totals and rates over San Luis Obispo and Santa Barbara
Counties. The second storm will bring widespread light to
moderate rain Thursday afternoon into early Friday. Dry with
gusty north to northeast winds will follow Friday Night through
the weekend.

&&

.SHORT TERM (TDY-THU)...03/1104 PM.

***UPDATE***

Temperatures ranged from the 70s to near 80 degrees over the
interior and many valleys, to cool 50s and 60s near the coasts.
Plenty of mid and high clouds streamed into the area from the
north today as the cold front neared, and this helped limit
warming. Rain chances start for the Central Coast overnight
tonight into early Tuesday, expanding to the Santa Barbara south
coast to the Ventura County coast and possibly even for south
facing slopes in the LA Basin into Tuesday afternoon. Current
amounts look on track with the highest rainfall totals expected
over northern San Luis Obispo County. Southerly winds will ramp
up quickly Tuesday night, with wind gusts possibly in the 45-55
mph range. Will likely need some wind advisories or warnings for
much of San Luis Obispo County and Santa Barbara County and may
also be needed for the mountains of Ventura and Los Angeles
County.

***From Previous Discussion***

Generally quiet conditions into early Tuesday as our storm system
approaches. Clouds and breezy south winds will be increasing.
Dense fog will be less expansive compared to this morning, but
will likely be with us again for areas south of Santa Barbara.

A low pressure system, currently centered over Vancouver Island,
is forcing a slow moving Atmospheric River, which is currently
focused over the California/Oregon Border. This whole system will
slide southward over the next 48 hours, holding steady in strength
and moving slowly for the first 24 hours, then weakening and
speeding up after. As a result, the highest rain totals and rates
remain focused over San Luis Obispo and Santa Barbara Counties,
with totals of 0.75 to 1.50 inches common and 1.5 to 3.0 inches
over the favored hills and mountains. There remains a small
fraction of projections with higher totals, so would expect a for
localized spots above these ranges. Peak timing will be Tuesday
morning to Wednesday morning. The one caveat is northwest San
Luis Obispo County, where rain could fall steadily for 24 hours
which would add up to much higher totals. Many projections are
showing totals in the 4 to 8 inch range, which usually vastly
under does our Rocky Butte rain-magnet gauge. For Los Angeles and
Ventura Counties, which will see the weaker period of the storm,
totals of 0.25 to 0.75 inches will be common with 0.75 to 1.5
inches in the favored hills and mountains which includes the
Palisades and Eaton burn scars. The one caveat for this general
area is the hills above Ojai, which could see totals over 2
inches. Peak timing will be late Tuesday Night into Wednesday
morning.

This will generally be a beneficial rain for the region. Snow
levels will be very high and above any major roads. The risk for
burn scar debris flows is very small. Flooding impacts should be
minor and confined to localized roads and clogged storm drains.
The one exception is for a moderate risk of more substantial
flooding of small creeks and roads in and downstream of the Santa
Lucias of northwest San Luis Obispo County. While the winds will
be gusty at times, especially off the Central Coast and in the
mountains, the risk for damage is small. LAX may see some east
winds however, which will cause some delays.

There will be plenty of breaks after the plume moves through by
later Wednesday which will continue into Thursday. Cannot
discount a shower or two however anywhere and anytime, especially
in the hills with fairly steady southwest flow aloft. Another
plume of moisture, currently over the middle of the Pacific, will
get picked up by the same low pressure system forcing our first
storm. This will bring us another round of widespread and steady
rain. The latest projections have sped the timing up a bit and
lowered the amounts. Based on the spread of the ensembles, would
imagine day-to-day variations to continue, so take the follow
with a little grain of salt. This storm looks more uniform than
the first in terms of amounts and rates. The best estimates call
for 0.25 to 1.00 inches in general, with 1 to 2 inches in the
favored hills and mountains. Peak timing looks to be Thursday
afternoon through Friday morning. Again, this will likely be
another round of beneficial rain.

While all of this rain will generally be beneficial, it still
looks like less than what we would need to completely end high
fire weather season. The rain should be sufficient to give us
temporary relief however, and limit any fire weather concerns for
the next couple of dry and windy spells (like this weekend).

.LONG TERM (FRI-MON)...03/212 PM.

If the slower projections play out, steady rain will be focused
over Los Angeles County Friday morning and afternoon, then rain
will trend quickly down Friday Night into Saturday as the flow
becomes northerly.

North to northeast winds look likely Friday Night through Saturday
or Sunday. Most projections favor more of a north wind event than
a true Santa Ana, but offshore flow looks locked in. There remains
a range of outcomes in terms of speeds, but a moderate event with
gusts of 30 to 50 mph looks very favorable in the ensemble
solutions and the general pattern. These winds should only be in
the typical wind prone areas like the I-5 Corridor, Ventura
Valleys, southern Santa Barbara County. They should not greatly
impact less common areas like the San Gabriel Valley. The airmass
will dry out rapidly, but lingering moisture will likely result in
some rain and snow showers over the north facing slopes Friday
Night. Temperature will be cool with highs in the mid 50s to mid
60s common, and chilly nights in the wind sheltered valleys.

Looking fuzzily out beyond that, there is a window for another
storm system for the middle to end of next week.

&&

.AVIATION...04/0651Z.

At 0514Z at KLAX, there was no marine layer. There was a sfc based
inversion with a top of 1900 feet deep and a temperature of 18 C.

Low confidence in all TAFs through 20Z then better confidence.
South of Pt Conception There is a 40 percent chc of low clouds
developing where they are not forecast and a 40 percent chc of no
clouds occuring at sites with low clouds forecast. Better
confidence after 20Z when most sites should have low VFR cigs.

KLAX...Low confidence in TAF through 20Z then better confidence.
There is a 40 percent chc of no low clouds. If low clouds do form
there is a 30 percent chc of BKN008 conds. Good confidence that
there will be no east wind component over 6 kt through 03Z.

KBUR...Low confidence in TAF through 20Z then better confidence.
There is a 40 percent chc of no low clouds. If low clouds do form
there is a 30 percent chc of BKN008 conds

&&

.MARINE...04/100 AM.

For the Outer Waters and Inner Waters along the Central Coast,
an approaching storm system will bring Small Craft Advisory (SCA)
level S to SW winds to the region, spreading from north to south
starting tonight (Mon night). SCA level winds are expected
(>90% chance) through Wednesday morning, with a 70-90% chance of
GALES for all waters north of Point Sal Tuesday afternoon through
late night. There is a 50-60% chance for GALES for northern
portions of PZZ673 (N of Pt. Arguello) for the aforementioned
timeframe. A lull is then likely before a return of periods of SCA
level winds, and potential gales Friday into the weekend.

For the Inner Waters south of Point Conception, sub advisory conds
are expected through early Tuesday. Tuesday afternoon through
Wednesday morning, there is a 60-80% chance for SCA winds across
the Santa Barbara Channel. There is 40-50% chance for western
portions of PZZ655. Sub advisory conds are expected until NW
winds enter the region early Friday morning, bringing a 30-40%
chance for SCA level conds into the weekend.

Widespread light to moderate rain will impact the Coastal Waters
as early as Tuesday morning through at least Thursday night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until noon PST today for zones
      645-670. (See LAXMWWLOX).
     Gale Warning in effect from noon today to 4 AM PST Wednesday
      for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect from noon today to 9 AM PST
      Wednesday for zones 650-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PST Wednesday for
      zone 673. (See LAXMWWLOX).

&&

PUBLIC...Phillips/Kittell
AVIATION...Rorke
MARINE...Black
SYNOPSIS...Kittell

weather.gov/losangeles

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