811
FXUS66 KLOX 301031
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
331 AM PDT Tue Apr 30 2024

.SYNOPSIS...30/248 AM.

Mostly clear skies and warmer temperatures will prevail across
the region through this week, although some night through morning
coastal low clouds and fog can be expected at times through
Wednesday. Gusty northwest to north winds will prevail over the
mountains and deserts through Wednesday, then turn NE and gusty
over portions of Ventura and Los Angeles Counties Wednesday night
into Thursday. There is a slight chance of rain with cooler
temperatures later in the upcoming weekend.

&&

.SHORT TERM (TDY-THU)...30/316 AM.

Slightly cyclonic NW flow over the area with 576 dam hgts over the
state. Moderate offshore flow from the north will combine with the
upper level NW flow and produce advisory level winds across the
mtns (including the Santa Ynez range) and the Antelope Vly. A weak
eddy has spun up due to the strong NW flow across the outer
waters. This eddy has brought low clouds to the LA coast and the
San Gabriel Vly. The offshore flow is not strong enough to in
these area to keep the low clouds at bay. The low clouds will,
however dissipate earlier than normal due to the offshore flow.
Most areas will warm 2 to 4 degrees today with local 6 degree warm
ups across the Central Coast and Santa Ynez Vly.

Stronger NW flow aloft tonight will keep the advisory level winds
going. There will be weaker offshore flow from the north and
actual onshore flow to the east which will bring more low clouds
to the csts and some lower vlys. The low clouds will dissipate by
or slightly after mid morning. The wind advisories continue
through mid afternoon but the latest high rez ensemble based
guidance indicates that the winds may come in lighter than
forecast and the advisories may be taken down early. The switch to
onshore flow to the east and the more extensive marine layer will
bring 2 to 3 degrees of cooling to most locations.

A little trof moves through the state Wed night and Thursday. At
the same time higher pressure will setting in to the NE and
offshore flow from the both the north and east will develop.
Look for a minimal Santa Ana event on Thursday morning. The winds
will most likely remain under advisory levels. The offshore flow
will chase away any low clouds and it will be a sunny day. Max
temps will warm with the lack of marine layer and compressional
heating. Most areas will see 2 to 5 degrees of warming.

.LONG TERM (FRI-MON)...30/331 AM.

The GFS and EC deterministic and mean ensembles are in good
agreement Fri and show hgts falling a late season upper low moves
southward down the coast. The offshore flow from north finally
turns onshore and the onshore flow to the east increases to
moderate levels. The marine layer stratus should make a decent
return and will be slower to clear. Look for 2 to 4 degrees of
cooling and a return to near normal temps.

The weekend forecast is looking a little clearer (well cloudier)
now as the EC is now trending to the wet GFS. Not all the way
however so there is still uncertainty in the 2 day forecast. The
upper low will move south and the swoop to the east. The big
question is how far will it swoop and when. The EC keeps the upper
low more to the north while the GFS persists in its track all the
way down to SBA county. The ensembles all pretty much take their
positions somewhere in between these two deterministic positions.
All in all for the two day period about a 50 percent chc of rain
for SLO and western SBA county and a 20 to 30 percent chc for SE
SBA county and LA/VTA counties. If rain does come to the area
rainfall totals will be in the tenth to quarter inch range. There
will be an increase in low mid and high clouds. Cooler for sure
with 3 to 6 degrees of cooling each day.

Drier NW flow is on tap for Monday with weaker onshore flow.
Rising hgts and sunnier skies will bring 2 to 5 degrees of
warming. MAx temps will still end up in the 60s and lower 70s or 4
to 8 degrees blo normal.

&&

.AVIATION...30/0712Z.

At 06Z at KLAX, the marine layer was 700 ft deep with an
inversion top at 1600 ft and a maximum temperature of 19 C.

High confidence in TAFs, except for KLAX, KLGB and KSMO (30% chc
of no cigs), and KOXR (15% chance of IFR cigs 14Z-17Z Tue). Light
turbulence and LLWS is possible over and near to hier trrn.

KLAX...Moderate confidence in TAF. There is a 30% chance of no
cigs developing through the period. Good confidence in any east
wind component remaining below 5 kts.

KBUR...High confidence in TAF.

&&

.MARINE...30/326 AM.

For the outer waters, current Gale Warnings look on track with
gusty NW gales expected to continue through at least tonight.
Swell will continue to be steep and choppy, a significant hazard
to small vessels in particular. Then, Small Craft Advisory (SCA)
conds are expected for the outer waters, Wednesday through Sunday.
However, there is a 30% chance of gales persisting into Wednesday
night and resurfacing again Thursday afternoon and evening.

For the inner waters N of Pt. Sal, SCA level winds are likely
through tonight. Then, there is a 60% chance of SCA winds during
the afternoon and evening hours Wednesday through Friday. Seas
are expected to be above SCA level through Wednesday.

For the Santa Barbara Channel, SCA level W-NW winds are expected
across the western portion during the afternoon through late
night hours today and Wednesday. Then, there is a 20-30% chance
of SCA winds each afternoon/evening Thursday and Friday across the
extreme western portion. Winds will likely remain below SCA
levels for eastern portions of the channel through Friday night.
Saturday afternoon through Sunday, there is a 30-40% chance of
widespread W to NW SCA level winds across the entire inner waters.

For the southern inner waters, there is a 20% chance of SCA level
W to NW winds across northwestern portions, near Anacapa Island
during the late afternoon through late evening hours through
Wednesday. Otherwise, good confidence in conds remaining below SCA
levels through Friday night. Saturday afternoon through Sunday,
there is a 30-40% chance of widespread W to NW SCA level winds
across the entire inner waters.

&&

.BEACHES...30/158 AM.

Persistent strong winds and outer water swell heights of 10-15
feet with a 10 second period will lead to high surf (8-12 feet)
along the Central Coast through tonight. Surf will be highest
across northwest-facing beaches. There is a 40% chance of high
surf advisory criteria lingering through Wednesday evening. NO
coastal flooding is expected.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 2 AM PDT Wednesday for
      zones 340-346. (See LAXCFWLOX).
     Wind Advisory now in effect until 3 PM PDT Wednesday for
      zones 349-351>353-376>378-381-383. (See LAXNPWLOX).
     Wind Advisory in effect until 3 PM PDT Wednesday for zone
      379. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Wednesday for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Wednesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Lund
MARINE...Lund/Phillips
BEACHES...Lund
SYNOPSIS...Sirard

weather.gov/losangeles

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