Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 232126
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
226 PM PDT Sat Mar 23 2024

.SYNOPSIS...23/123 PM.

Scattered showers with isolated thunderstorms are possible into
Sunday with snow levels lowering to as low as 4000 feet. Gusty
west to northwest winds are expected as well. Dry and warmer
weather is expected Monday through at least Wednesday. More storms
are possible Friday into next weekend with heavy rain possible at
times.

&&

.SHORT TERM (TDY-TUE)...23/148 PM.

The initial front moved through the area this morning with
rainfall amounts around a half inch on average, though a little
less in LA County. The transition to a showery/convective regime
is in progress, though that won`t fully take effect until Sunday
when the upper low arrives with much colder air aloft. Can`t rule
out an isolated heavy shower or even a storm this afternoon,
though best chance for that would be in SLO County. Moderate
northwest to west flow is developing across the area this
afternoon with winds in the 25-35 mph range along the coast and
over the coastal waters. Those will settle down overnight over the
land but resume Sunday with even stronger gusts and advisories
have been issued for all coastal areas tomorrow afternoon.

Increasing lapse rates and cooling aloft will provide an
increasingly favorable environment for convective activity Sunday
afternoon, especially north of Pt Conception and in LA County.
Can`t rule out a storm elsewhere but downslope flow off the
mountains will be a limiting factor. Locally heavy rain, small
hail, and gusty winds all possible with the storms. For some areas
the rain for this weekend is over but areas north of Pt
Conception, the mountains, and in LA County are most likely to see
at least some additional precip by tomorrow. Lowering snow levels
also expected tonight into Sunday with that cooler air moving in.
Still expecting snow levels to drop to the low 4000s early Sunday
and again Sunday evening with a 30-50 percent chance of light snow
near the Grapevine summit on Interstate 5. Increasing northerly
flow later Sunday will create some gusty winds up to 50 mph in
the mountains and across southern Santa Barbara County. Some of
those northerly winds will filter down into the western LA
valleys and coastal areas Sunday night but likely below advisory
levels.

Dry and warmer weather expected Monday and Tuesday with some
breezy northerly winds at times, especially in the mountains.

.LONG TERM (WED-SAT)...23/225 PM.

Dry and warmer again Wednesday with highs jumping into the low to
mid 70s in the valleys. Then turning cooler Thursday as the first
of two storm systems approaches from the northwest. Can`t rule out
a shower northern areas Thursday though models have scaled back
in recent runs and only about a third of the ensembles have precip
reaching SLO County. At most it would be very light rain.

A second system is expected to dumbbell around the first upper
low later Thursday and drop much farther south Friday through the
following weekend. Deterministic models have the low center as
low as 529dam Friday afternoon just west of the Bay Area. Based on
the latest ensembles precip chances are expected to increase
Friday night with all areas getting either rain or mountain snow
by Saturday and continuing into Sunday and possibly even early
Monday as the upper low is mostly cut off from the westerlies and
very slow moving. If the track and timing remain reasonable stable
this could deliver a significant amount of rain to the area.
Ensemble solutions are currently indicating roughly 1-3 inches of
rain at lower elevations and possibly up to twice that in the
upslope areas. There are a number of solutions that are even
higher than that. And given how cold this system is with
thicknesses down to 540, this could also be a big snow producer
for the mountains.

&&

.AVIATION...23/1820Z.

At 18Z at KLAX, there was no marine layer nor inversion. There
was a deep moist layer.

Moderate confidence in TAFs through 06Z with low confidence after
that. Generally VFR conditions are expected to prevail through 06Z
except MVFR to locally IFR near convective showers. Convective
showers will increase in coverage from northwest to southeast
through 06Z. There is a less than 10 percent chance of a
thunderstorm during this time focused from SMX and north. There is
a 10-20 percent chance of a thunderstorm between 12-00Z KSMX and
north and elsewhere between 18-00Z Sunday.

KLAX...Moderate confidence in TAF. The threat for east winds has
ended and not expected through the TAF period. Convective showers
may return in the 00-06Z window and continue off and on through
the period. VFR conditions are expected to prevail except MVFR to
brief IFR conditions in heavier showers. There is less than a 10
percent chance of a thunderstorm as early as 00Z, with chances
increasing to 10-20 percent 18-00Z Sunday

KBUR...Moderate confidence in TAF. There will likely (80-90
percent chance) be a break in shower activity between 20-00Z with
convective showers likely returning in the 00-06Z window and
continuing at times through the period. There is a 10-20 percent
chance of a thunderstorm after 00Z, with highest chances after 18Z
Sunday.

&&

.MARINE...23/114 PM.

Dangerous seas are likely this afternoon through Monday,
especially on Sunday when widespread Gales are nearly certain. The
strongest winds will be focused across all the waters south of
Point Sal, with winds dropping below Gale Force at times northward
of Point Sal. There is a 30 percent chance of Gales starting this
evening for the Santa Barbara Channel and the Santa Monica Basin
and 50-70 percent chance for the inner waters south of Point Mugu
with particular focus between Point Mugu and Palos Verdes. As
such, have started the Gale Warning now with the afternoon package
for the inner waters south of Point Mugu. There is a 40 percent
chance that the current Gale Watches will need to be extended
through Monday for the waters south of Santa Barbara. In addition
to the winds, there is a 10 to 20 percent chance of thunderstorms
this evening through Sunday early evening with the potential for
locally gusty winds, brief heavy rainfall and/or hail, and
dangerous cloud to surface lightning. Conditions will improve
Tuesday and Wednesday, but it will still be hazardous to most
small craft due to choppy seas. Winds and seas will increase once
again on Thursday and Friday with widespread Gale Force Winds
possible.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect from 3 AM Sunday to 9 AM PDT
      Monday for zones 87-340-346-354-362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 645-650-655-670-673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 AM Sunday to 3 AM PDT Monday
      for zones 645-650-655-670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW
AVIATION...Munroe
MARINE...Munroe/Lund/RK
SYNOPSIS...MW

weather.gov/losangeles

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


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