178
FXUS66 KLOX 051020
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
320 AM PDT Sun Apr 5 2026

.SYNOPSIS...04/1053 PM.

It will be a little cooler today across the coasts and lower
valleys. Today`s highs, however, will remain 10 to 12 degrees
over normal. A cooling trend will begin Monday with temperatures
back to near normal around mid week. Rain is likely sometime
between Thursday and Saturday.

&&

.SHORT TERM (TDY-TUE)...04/1138 PM.

The offshore flow this morning will be much weaker (~1 mb) and
will only produce local NE winds 15 to 25 mph. At the upper
levels...ydy`s ridge will push off to the east and will be
replaced with falling hgts and SW flow. Skies, currently, are
clear from north or Monterey to south of San Diego. There is 30 to
40 percent chc that some low clouds will develop in a weak eddy
and affect the LGB/LAX area in the morning, but its more likely
that the low clouds will hold off until Monday morning. 2 to 4 mb
of onshore flow this afternoon from both the W and S will bring 3
to 6 degrees of cooling to the csts and lower vlys, while the
warmer atmosphere will allow for 2 to 4 degrees of warming across
the mtns and far interior. Most max temps today will end up about
12 degrees above normals.

And eddy, weak cyclonic flow aloft and onshore flow will all
combine to bring a marine layer stratus deck to most of the coasts
and isolated portions of the lower vlys.

Monday will have mostly sunny skies, except for the coastal low
clouds in the morning. Stronger onshore flow and continued
falling hgts will bring 4 to 8 degrees of cooling to the coasts
and vlys and 2 to 4 degrees over the rest of the area.

Offshore flow from the north arrives later Monday night and
Tuesday. Hi Rez mdls are forecast a dramatic retreat in the amount
of morning low clouds with only the LGB/LAX area forecast to
receive the low clouds. There, is however, a decent chc (30-40
percent) that the low cloud coverage will be more robust. A strong
W to E gradient will combine with the northerly offshore flow to
produce gusty winds in the western Antelope Vly, the I-5
corridor and the western portion of the SBA south coast. Max temps
will be very similar to Monday, except for the VTA county coast
where an enhanced sea breeze will bring noticeable 2 to 4 degrees
of cooling.

.LONG TERM (WED-SAT)...05/1204 AM.

A ridge will be overhead on Wednesday. Hgts will be near 576 dam.
Pressure gradients will be similar to Tuesday with moderate
onshore flow to the east and weak to moderate offshore flow from
the north. Mdls continue to show limited of no marine layer
clouds, but like Tuesday there is a fair chc that there will be
some in the early morning. There will be gusty winds through the
I-5 corridor and the SBA mtns (including the Santa Ynez range).
Right now it looks like the winds will come in just under advisory
criteria.

The long range mdls are consistent with the idea of a storm in the
Thursday through Saturday time frame. There is still a great deal
of disagreement on the details of this system. Broadly, there is a
80 percent chc of rain during the three day period but only a 20
to 30 percent chc of rain during any given 6 hour period. Some
solutions bring a cold core upper low directly over the area and
this would bring an enhanced convective threat.

Most mdls and ensembles favor a rainfall total of about a half
inch of the course of the storm. Some solutions particularly the
EC`s show 1 inch amounts. This system should gradually come into
better focus over the next 48 hours.

&&

.AVIATION...05/1019Z.

At 0822Z at KLAX, There was no marine layer. There was a sfc
based inversion. The top of the inversion was 900 feet with a
temperature of 25 C.

High confidence in all TAFs through 08Z. Moderate confidence in
low clouds timing and cig hgts for all coastal sites aft 08Z.

Low confidence in TAFs KLAX, KSMO and KLGB with a 40 percent chc
of LIFR conds 12Z-17Z.

KLAX...High confidence in TAF through 08Z. Moderate confidence aft
08Z. Low cloud arrival is possible any time from 08Z to 13Z. Cig
hgts could be anywhere from 002 to 008. No significant east wind
component is expected.

KBUR...High confidence in TAF.

&&

.MARINE...04/1059 PM.

For the Outer Waters, moderate to high confidence in current
forecast. High confidence that today`s winds and seas will
remain below Small Craft Advisory (SCA) levels. For Monday
through Wednesday, high confidence in SCA level winds, likely to
start early Monday morning for the outer zones west and south of
Point Conception. For the northernmost zone, SCA winds are likely
to be delayed until late Monday afternoon. On Thursday, there is a
50-70% chance of SCA level winds for the two southern zones, and
a 20-30% chance of GALE force gusts.

For the Inner Waters north of Point Sal, moderate confidence in
current forecast. High confidence that today`s winds and seas will
remain below Small Craft Advisory (SCA) levels. For Monday
through Wednesday, there is a 60-80% chance of SCA level winds in
the afternoon and evening hours. On Thursday, there is a 30-40%
chance of SCA level winds in the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate
confidence in current forecast. High confidence that today`s winds
and seas will remain below Small Craft Advisory (SCA) levels. For
Monday through Tuesday night there is a 50-70% chance of SCA
level winds across the western half of the Santa Barbara Channel.
For Wednesday through Thursday, there is a 60-80% chance of SCA
level winds across all of the southern Inner Waters. Additionally,
there will be a 30% chance of GALE FORCE winds Wednesday night,
with the best chance in the Santa Barbara Channel.

There will be a chance of dense fog this morning south of the
Channel Islands, and mainly over the southeast portion of PZZ655,
between Catalina Island and the southern LA Coast.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM Monday to 3 AM PDT
      Tuesday for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM Monday to 3 AM PDT
      Wednesday for zones 650-670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 AM Monday to 3 AM PDT
      Wednesday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...RAT/CC
SYNOPSIS...30

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office