312
FXUS66 KLOX 180954
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
254 AM PDT Sat May 18 2024

.SYNOPSIS...18/245 AM.

A stagnant May Gray pattern will continue through most if not all
of next week. Low clouds with occasional drizzle and temperatures
well below normal will dominate the coastal side of the
mountains. Generally clear skies with gusty onshore winds and
temperatures around normal will be the norm on the interior side.

&&

.SHORT TERM (TDY-MON)...18/245 AM.

Little change expected over the weekend. Typical high pressure
aloft with stronger than normal onshore pressure gradients will
maintain a healthy May Gray marine layer pattern. Low clouds will
continue to push well into the coastal slopes with poor afternoon
clearing near many coastal areas and some coastal valleys. Some
drizzle should be expected over portions of the area each morning,
especially from Santa Barbara through Malibu. The clearing
pattern each day will likely have some differences that are
impossible to predict, but the general gloomy story overall is
locked in. The onshore gradients will also fuel breezier than
normal onshore winds over the interior areas, strongest over the
Antelope Valley with gusts in the 30 to 40 mph range common each
afternoon and evening. Not expecting the need for any Wind
Advisories. This downsloping flow and high pressure aloft will
maintain temperatures at or just above normal over the interior
areas. The high clouds that we are seeing right now will quickly
depart to the northeast by mid-morning Saturday.

On Monday a weak low pressure system, currently centered 1000
miles west of Los Angeles, will pass through extreme southern
California will drawing a deeper trough passing through the
northwest states down closer to California. This will bring some
noticeable changes. Temperatures will drop to below normal for the
interior areas. Coastal and valleys areas will also drop a few
degrees, and will likely see an even deeper marine layer and more
drizzle. Low clouds could even push into some interior valleys
like Cuyama and the Antelope Valley. Southern Santa Barbara County
and western Ventura County would be the one exception, as
increasing northwest flow will likely bring an area of low cloud
clearing in the morning or early afternoon. This would locally
counteract the cooling factor there, and form a coastal eddy to
the east. There is chance that the marine layer grows too deep to
support itself, with more clearing than we have been seeing
overall by Monday afternoon.

.LONG TERM (TUE-FRI)...18/252 AM.

As the aforementioned low pressure system moves to the east on
Tuesday and Wednesday, this will weaken the onshore pressure
gradients and flow (LAX-DAG predicted to go from +6 millibars
Monday morning to +2 millibars on Tuesday). This should cause the
marine layer to lower some and not push as far inland as it has
been. The northwest flow over Santa Barbara County and the
northern mountains will also continue to make low clouds over
southern Santa Barbara and western Ventura Counties less
favorable. As a result, Tuesday and Wednesday will likely be the
warmest over coastal and valleys areas over the last week or two
with coastal temperatures starting to sniff normal values. Beyond
that there is a fair amount of uncertainty. Several of the
ensemble members show further warming to close out the week, while
a significant amount show onshore flow strengthening and the
marine layer expanding once again. The most likely outcome is a
return to conditions like we have been seeing by Thursday or
Friday of next week, with cool and cloudy conditions on the
coastal side of the mountains, with warmer than usual and breezy
conditions over the interior.

&&

.AVIATION...17/2351Z.

At 2350Z at KLAX, the marine layer was 3000 ft deep. The top of
the inversion was 5400 feet with a temperature of 20 C.

Overall for the 00Z TAF package, high confidence for desert TAFs
and moderate confidence in coastal/valley TAFs. Lower confidence
for coastal/valley sites due to uncertainties with flight category
changes with the marine layer stratus.

KLAX...Moderate confidence in 00Z TAF. MVFR to VFR cigs expected
through much of the forecast period. Any east wind component
on Saturday morning is expected to be 6 kt or less. There is a
20 percent chance of clearing on Saturday afternoon.

KBUR...Moderate confidence in 00Z TAF. MVFR cigs expected through
early Saturday afternoon. There is a 20 percent chance of no
clearing on Saturday afternoon.

&&

.MARINE...17/1033 PM.

For the Outer Waters, generally high confidence in current
forecast. Tonight through Saturday, winds and seas will remain
below Small Craft Advisory (SCA) levels. On Sunday, SCA level
winds will develop across PZZ670 then spread into PZZ673/676
Monday through Wednesday with the potential for SCA level seas
also.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Tonight through Saturday, high
confidence in winds and seas remaining below SCA levels. For
Sunday through Wednesday, there is a 50% chance of SCA level
winds in the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For a majority of the area, high
confidence in winds and seas remaining below SCA levels tonight
through Wednesday. However across the western half of the Santa
Barbara Channel, there is a 30-40% chance of SCA level winds
Monday through Wednesday, mainly in the late afternoon and evening
hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Kittell
AVIATION...Gomberg
MARINE...Phillips/RAT
SYNOPSIS...RK

weather.gov/losangeles

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