Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 261624
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
924 AM PDT Tue Mar 26 2024

.SYNOPSIS...26/910 AM.

Skies will be partly cloudy through Wednesday with a slight
warming trend. A weak system will bring light rain to the Central
Coast Thursday. A more significant storm moves into the region
Friday and will last through the weekend, possibly bringing heavy
precipitation and gusty winds.

&&

.SHORT TERM (TDY-THU)...26/924 AM.

***UPDATE***

A couple of quiet weather days on tap with just some patchy night
and morning low clouds and some breezy north winds in the
mountains and southern Santa Barbara County. Temperatures expected
to warm slightly but remains slightly below normal in most areas.
A weak system is expected to bring some light rain to the Central
Coast Thursday with amounts less than a quarter inch in most
areas.

A more significant storm is still expected for late Friday into
the weekend. Ensembles are wavering a bit on the rain totals which
is to be expected with a cutoff low. While there is still a wide
range of possibilities, most of the current guidance, including
the ECMWF EFI, is suggesting a highly enamel`s event for this time
of year.

***From Previous Discussion***

Not too much to talk about in the short term (All eyes are on the
long term) NW flow today will give way to ridging on Wednesday
which will transition to broad cyclonic flow on Thursday. There
will be weak (morning) to moderate (afternoon) onshore flow to the
east each day. There will be weak offshore flow from the north
through the period.

Low clouds will be the major forecast problem over the next few
days. Currently there are plenty of low clouds across western SBA
county and patch low clouds over the csts and lower vlys of LA
county. The latest satellite imagery shows some low clouds trying
to sneak into the VTA county cst as well. North flow has brought
some upslope clouds to the north slopes along the Kern County Loo
line. Look for similar low cloud coverage both Wed and Thu
mornings.

One small think of note is a weak frontal passage over SLO county
on Thursday morning which will bring a small chc (20 percent) of
rain in the morning.

Max temps will fluctuate a few degrees each day, but max temps
across the csts/vlys will mostly be in the mid 60s to lower 70s
which is about 2 to 4 degrees blo normal.

The strong NW upper level flow will bring advisory level gusts to
the SW portion of

.LONG TERM (FRI-MON)...26/331 AM.

Deterministic mdls and their ensembles are all converging on a wet
solution for the Friday to Sunday period with a likely rainfall
maximum later Friday night into Saturday morning.

Friday morning a 534 dam upper low to the west of Portland will
begin to spin down the coast. Late Friday night the low will be
just west of the Bay Area and by late Saturday night it will be
just off of Pt Conception. By late Sunday the low will be
incorporated into a very large pos tilt trof spanning half the
nation.

Rain will approach SLO county Friday morning and will like spread
over most of SLO and western SBA county Friday afternoon. The main
event will start Friday evening and last into Saturday as the
maximum are of PVA and S flow overspreads the area. The rain will
taper off Saturday night but then a convective showery regime will
set up as the very cold upper low moves over the area and brings
significant atmospheric destabilization with it.

The current rainfall forceast looks good and on track with 1 to 3
inches csts/vlys and 3 to 6 inches across the south facing slopes
and NW SLO county. Snow levels expected to hold around 6000 feet
through Saturday, but above that level there could be snow
accumulations in excess of 2 feet, and at even elevations above
7500 feet as much as 3-4 feet.

The rain will turn to showers on Sunday and continue into Monday
as the upper low moves overhead. The -29 degree 500 mb temps and
the late March sun angles could well combine to generate strong
thunderstorms and possible waterspouts and even small tornados.

Also, given the state of our hillsides after the heavy rain
earlier this season it`s very likely that this storm will create
many additional mud and rock slides in the hills and mountains so
residents in those areas are urged to take any precautions as soon
as possible.

&&

.AVIATION...26/1042Z.

Around 0845Z, the marine layer depth was around 1800 feet deep at
KLAX. The top of the inversion was 3500 ft with a temperature near
8 degrees Celsius.

High confidence in the current forecast for the desert terminals.
Moderate confidence for the coastal and valley terminals. There is
a moderate-to-high chance of MVFR conditions through 17Z for
coastal and valley terminals, and again after 08Z Wednesday. There
is a moderate chance of moderate wind shear and turbulence between
23Z and 07Z at KSBA.

KLAX...There is a 60 percent chance of MVFR conditions through
17Z, then VFR conditions should develop. After 08Z Wednesday,
there is a 50 percent chance of MVFR conditions increasing to 70
percent by 13Z Wednesday. There is a 20 percent chance of
easterly winds between 7 and 10 knots between 14Z and 17Z,
otherwise wind should remain less 7 knots.

KBUR...There is a 60 percent chance of MVFR conditions through
16Z, then VFR conditions should develop. After 10Z Wednesday,
there is a 40 percent chance of MVFR conditions. No wind impacts
are expected at this time.

&&

.MARINE...26/913 AM.

No significant changes with the morning update.

Moderate-to-high confidence in the current forecast through
Thursday, then moderate confidence thereafter. Higher confidence
exists in the wind forecast relative to the sea forecast.

For the waters outside the Channel Islands to southwest through
northwest and along the Central Coast, a 60-90 percent chance of
Small Craft Advisory winds from near Point Sal south to southeast
to San Clemente and San Nicolas Islands will increase and spread
northward into this afternoon and this evening. Widespread SCA
conditions are expected to develop by this evening. Winds and seas
will diminish between late this evening and into Wednesday
morning, but there is a high chance of SCAs being extended for the
to the southwest and west of the Channel Islands from Point
Conception to San Nicolas Islands into Wednesday morning. Winds
and seas will fall below SCA levels for Wednesday afternoon
through Thursday afternoon, then there is a moderate-to-high
chance of SCA conditions returning on Thursday night through the
weekend.

Inside the southern California bight, there is a 20-50 percent
chance of Small Craft Advisory winds this morning, increasing to
30-70 percent chance by this evening. The highest chance are for
the western and central portion of the Santa Barbara Channel,
while the lowest chance are for southeastern portion of the inner
waters. By late tonight, winds and seas will fall below SCA
levels through at least Thursday afternoon. There is a moderate-
to-high chance of SCA conditions returning on Thursday night
through the weekend.

&&

.BEACHES...26/350 AM.

A return of high surf is expected between Thursday night and the
weekend as a storm system will bring a large northwesterly swell
to the region. Surf as high as 10 and 13 feet is expected at
Central Coast beaches, and 4 to 7 feet at Los Angeles and Ventura
County beaches. Surf should peak on Saturday or Saturday night.
Strong and dangerous rip currents are expected during this
period.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 3 PM this afternoon to 3 AM PDT
      Wednesday for zones 349-351-378. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 9 PM PDT this evening
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 650-670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Rorke
AVIATION...Hall
MARINE...RM/Hall
BEACHES...Hall
SYNOPSIS...MW

weather.gov/losangeles

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


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