571
FXUS66 KLOX 310630
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1030 PM PST Thu Jan 30 2025

.SYNOPSIS...30/411 PM.

A slight warming trend is expected Friday through the weekend,
though areas of low clouds and fog are possible for coast and
valleys, keeping temperatures a few degrees below normal. Light
showers are possible north of Santa Barbara over the weekend as
the southern end of a storm system moves into the Central Coast.
Rain is likely across the entire region late next Tuesday into
Wednesday with periods of moderate to heavy rain possible.

&&

.SHORT TERM (THU-SUN)...30/1029 PM.

***UPDATE***

Warming was impaired by widespread marine layer clouds today, with
highs in the 50s to near 60 degrees throughout much of the area.
Expecting less low clouds on Friday, but high clouds are already
starting to move in from the front to the north. These high clouds
could disrupt the formation of low clouds and fog, especially up
north. Rain will begin along the Central Coast Friday, and current
forecast generally look on track. However, given the high PWAT
values up to 1.3 inches and IVT values rising to around 500 kg/m*s
by Saturday. POPs were bumped up a bit for the Ventura County
Mountains and I-5 corridor area Saturday to support this, and
consistent with the NAM-12 and SREF guidance. May need to increase
totals/pops a bit more, as many areas could see light sprinkles
if things shift a little further south, however will hold off for
now. Heights trend up into the weekend, reaching 583 dam by Sunday
allowing for a warming trend despite rain chances and clouds.

***From Previous Discussion***

A reverse clearing developed today which is an unusual occurrence
this time of year. The marine layer rocketed up to over 5000 feet
south of Pt Conception this morning with a weak eddy circulation and
has struggled to clear over land, but there are far fewer clouds
over the cold ocean surface. Stratus was slow to clear along the
Central Coast as well.

Forecast soundings are showing a much lower marine inversion
Friday morning and models are indicating a moderate offshore
gradient trend as well. These factors should lead to less marine
layer clouds Friday in general as well as earlier clearing.
Temperatures are expected to begin a modest warming trend that
will continue in the weekend, though not as warm as the forecasts
earlier in the week were showing. Gradients are expected to trend
back onshore Saturday and especially Sunday so forecast highs this
weekend, which were once in the mid to high 70s, are now in the
low 70s at best, and more likely mid to high 60s.

For the Central Coast this weekend, the tail end of the AR system
over northern California will dip south into SLO and possibly
northern Santa Barbara Counties. Light rain is possible as early
as Saturday morning along th SLO coast, with off and on light
rain through Sunday before the AR axis briefly shifts to the
north. Rain amounts this weekend near the coastal SLO/Monterey
border could reach a half inch and locally higher in the coastal
mountains. Rain chances drop off pretty quick to the south but
can`t rule out a few sprinkles as far south as Pt Conception.

.LONG TERM (MON-THU)...30/230 PM.

Models have been pretty consistent showing the moisture axis
briefly pushing back north Monday leading to decreasing shower
chances across the Central Coast. And continued dry weather south
of Pt Conception with near to slightly below temperatures.

On Monday night into Tuesday a cold upper low drop south out of
Canada and will park itself just west of the WA/OR border. This
will push the AR back south bring rain back to the Central Coast
Tuesday and into southern areas including LA County Tuesday night
into Wednesday. While the ensemble solutions are still exhibiting
some ups and downs in the rain amounts and timing, confidence
remains high that all areas will receive at least light to
moderate rain amounts (1" coast/valleys, 2-3"
foothills/mountains) by Wednesday night. There`s about a 10-30%
chance of double those amounts. Higher confidence exists from
Santa Barbara north due to the most likely southern extent of the
AR.

This will be a much warmer storm as PW`s are over 1" and the
source region is much farther south than the last system. So
little to no snow expected below 8000 feet.

Showers are possible into Thursday morning, though most of the
model solutions show rain tapering off Wednesday night.

&&

.AVIATION...31/0559Z.

At 0450Z at KLAX, the marine layer was 4000 ft deep. The top of
the inversion was at 5100 feet with a temperature of 11 C.

High confidence in the TAFs for KPMD and KWJF.

Low confidence in the remainder of the TAFs. Sties with cigs
forecast have a 40 percent chc of no cigs. Sites with no cigs
forecast have a 40 percent chc of low clouds (likely low MVFR but
a chance of IFR). Good confidence that all sites will be VFR by
20Z.

KLAX...Low confidence in TAF through 20Z then high confidence.
There is a 40 percent chc of low clouds forming (if low clouds do
form there is a 70 percent chc of BKN012 conds and a 30 percent
chc of BKN008 conds). Any east wind component expected.

KBUR...Low confidence in TAF through 20Z then high confidence.
There is a 40 percent chc BKN008 conds 09Z-16Z.

&&

.MARINE...30/835 PM.

In the Outer Waters, conditions should remain fairly benign
before chances increase for Small Craft Advisory (SCA) level winds
this weekend. The areas favored will be for the waters around
Point Conception and the Channel Islands. The best chances will
be around 40 percent, Sat afternoon/eve and again on Tue.

In the Inner Waters north of Point Sal, SCA conds are not
expected thru Mon with a 30 percent chance Tue and Tue night.

For the Inner Waters south of Point Conception, winds will begin
to increase Friday afternoon, with a 40 percent chance of SCA level
winds Saturday afternoon through Sunday, mainly in the Santa
Barbara Channel.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Phillips/MW
AVIATION...Rorke
MARINE...Ciliberti
SYNOPSIS...MW/Smith

weather.gov/losangeles

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