890
FXUS66 KLOX 301852
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1152 AM PDT Tue Apr 30 2024

.SYNOPSIS...30/857 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. Locally
breezy winds will continue over the mountains and deserts through
Wednesday, then turn NE over interior portions of Ventura and Los
Angeles Counties Wednesday night into Thursday. Cooler
temperatures are expected Friday through the weekend with a
slight of rain.

&&

.SHORT TERM (TDY-THU)...30/922 AM.

***UPDATE***

Marine layer this morning is close to 2000 feet deep but was
primarily just impacting coastal LA County, though it has crept up
to the Ventura County coast as well. Gusty north winds overnight
have tapered off but some local gusts to around 40 mph still
ongoing through the Grapevine between Whitaker Peak and the Kern
County line. Winds are continuing to decrease and will likely end
the wind advisory this morning. An uptick in winds are expected
again this evening and overnight tonight but winds expected to
remain at or below 40 mph.

One potentially notable change in the forecast for Thursday is
that models now are much weaker with the offshore push. The LAX-
DAG gradient was forecast to drop to -5.1mb but today`s NAM has
brought that almost all the way back to 0. So the big warm up for
Thursday will likely not happen and any northeast winds would be
confined to the far interior areas at most.

***From Previous Discussion***

Tonight 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 switch to onshore flow to
the east and the more extensive marine layer will bring 2 to 3
degrees of cooling to most locations Wednesday.

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...30/1851Z.

At 1122Z at KLAX, the marine layer was 1800 ft deep with an
inversion top at 3500 ft and a maximum temperature of 16 C.

Moderate confidence in LA County coast and valley TAFs. Low
confidence on KSBA, KOXR, and KCMA, with a 20% chance of no cigs
developing, and a 20% chance cigs a category lower than
forecasted. High confidence in all other TAFs. Timing of cig
arrival/clearing may be off by +/- 2 hours, with a 20% chance of
cig developing once category lower than forecast at times.

KLAX...Moderate confidence in TAF. Timing of cig arrival/clearing
may be off by +/- 2 hours, with a 20% chance of a couple hours of
cigs lowering to BKN008. There is a 20% chance of an east wind
component reaching 6-8 kts from 08Z-16Z Wed.

KBUR...Moderate confidence in TAF. Timing of cig arrival/clearing
may be off by +/- 2 hours, with a 20% chance of a couple hours of
cigs lowering to BKN008.

&&

.MARINE...30/929 AM.

For the outer waters, current Gale Warnings are on track with
gusty NW gales expected to continue until late tonight. Swell
will continue to be steep and choppy. After gales subside, 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.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 2 PM PDT Wednesday for
      zones 340-346-354. (See LAXCFWLOX).
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...MW/Rorke
AVIATION...Schoenfeld
MARINE...Lund/Schoenfeld
SYNOPSIS...MW/Sirard

weather.gov/losangeles

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