Area Forecast Discussion
Issued by NWS Los Angeles, CA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS66 KLOX 121041

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
341 AM PDT Fri Apr 12 2024

.SYNOPSIS...12/248 AM.

Much cooler weather is expected today through the weekend as
another late season storm moves into the region. Rain will begin
tonight with showers lasting through Sunday. Snow is expected at
higher elevations. A warming trend will begin Monday with dry
weather next week.


.SHORT TERM (TDY-SUN)...12/340 AM.

Increasing onshore flow and a deepening marine layer ahead of the
approaching storm will push much cooler air into the interior
today. Low clouds and fog have already moved into the LA/Ventura
valleys and the deepening trend will continue through the morning.
Can`t rule out some drizzle at times, especially near the
foothills. Clearing will be slow and likely incomplete while
temperatures tumble to the mid 60s to lower 70s after highs
Thursday near 90 in the warmer valleys.

A cold upper low is dropping south and at 3am is about 600 miles
west of the CA/OR border. It`s expected to start turning towards
the coast Friday afternoon with increasing light pre-frontal rain
chances as early as Friday evening along the Central Coast down to
Santa Barbara and into Ventura and LA Counties by Saturday
morning. The main frontal band with light to moderate rain rates
will follow that, coming through the Central Coast and Santa
Barbara Saturday morning, and late morning through afternoon for
Ventura and LA Counties. The front is expected to exit LA County
early Saturday evening. Snow levels through Saturday expected to
mainly be above 6000 feet. A winter weather advisory has been
issued for the Santa Barbara and Ventura mountains starting
Saturday morning and lasting through Sunday afternoon. May need
one for the eastern San Gabriel Mountains as well but with the
precip starting later Saturday decided to hold off on that one for

After a brief decrease in shower coverage Saturday evening, a
second upper low is expected to come through the area Sunday with
even colder air. Rain coverage and intensities are expected to
increase area-wide Sunday with a chance for thunderstorms,
mainly along the Central Coast but there`s a 10-15 percent chance
across southern areas as well. Snow levels could drop to as low as
4000 feet briefly Sunday morning, then settle around 5000 feet
most of the day.

Rain amounts through Sunday are holding steady at around an inch
along the Central Coast and Santa Barbara, to around a half inch
across LA/Ventura Counties. Amounts up to 2 inches possible in the
south facing foothills and mountains. Several inches of snow
possible above 6000 feet.

.LONG TERM (MON-THU)...11/135 PM.

The ridge rebuilds on Monday kicking off a drying and warming
pattern. The ridge axis will be to our west and with a negative
tilt, leaving the area near the inflection point between the
ridge and a conus-spanning trough. Expect partly cloudy skies.
Heights will be back up to about 576 dam on Tuesday and Wednesday.
Afternoon 80`s are possible as soon as next Wednesday in the
warmer valleys. The pattern will become more zonal by Thursday
with heights dropping a few dam, and introducing slight cooling.



At 00Z, the marine layer depth was 800 feet deep with the top of
the inversion at 2300 feet with a temperature of 23 C.

Moderate confidence in TAFs. Expecting marine layer clouds to
reach coastal valleys sites, with lower confidence in arrival
times and may briefly have dense fog at coastal sites. Arrival of
cigs may be off by +/- 2 hours this evening.

KLAX...Moderate confidence in TAF. Periods of 1/4SM vsby are
possible from 08Z-14Z Fri. There is the potential for an extended
period of southeast winds, with an east wind component around 5 kt
from 13Z through 22Z, and an east wind component up to 8 kt from
23Z through 06Z.
KBUR...Arrival of OVC008-OVC015 cigs may be off by +/- 2 hours
late tonight, and there is a slight chance of periods of 1/4SM
vsby from 10Z-15Z Fri.


.MARINE...11/1011 PM.

Moderate confidence in the forecast. Slightly higher confidence
in winds relative to seas.

For the outer waters and the inner waters north of Point
Conception, there is a 40-70 percent chance of Small Craft
Advisory (SCA) level winds this afternoon and tonight, highest for
the northernmost outer waters. Starting Friday afternoon SCA
winds are likely for the waters north of the Channel Islands.
Saturday through Tuesday night, there is a 60-80 percent chance of
widespread SCA conditions developing. There is a 20-30% chance of
GALES Tuesday through Wednesday morning, highest beyond 30 NM

For the inner waters south of Point Conception, winds and seas
will likely remain below SCA levels through Friday night, then
there is a 50-70% chance of SCA level winds developing Saturday.
For early next week, SCA level winds will likely affect the
western portions of the inner waters with a 40-60 percent chance
of SCA level conditions, with the highest chances during the
afternoon and evenings.

Dense fog, with visibilities of one nautical mile or less, will
impact the coastal waters through Friday morning.


CA...Winter Weather Advisory in effect from 5 AM Saturday to 5 PM
      PDT Sunday for zones 353-376-377. (See LAXWSWLOX).
PZ...Small Craft Advisory in effect from 9 PM this evening to 9 AM
      PDT Saturday for zones 645-650-670-673. (See LAXMWWLOX).




Experimental Graphical Hazardous Weather Outlook at: is the U.S. government's official web portal to all federal, state and local government web resources and services.