111
FXUS66 KLOX 120425
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
925 PM PDT Sat May 11 2024

.SYNOPSIS...11/917 PM.

A persistent marine layer depth in place will keep night through
morning low clouds extending into the coast and valleys and
temperatures near seasonal averages. Slight warming will take
place on Sunday as weak high pressure aloft builds over the area,
then a gradual cooling trend will establish through Wednesday as
onshore flow strengthens.

&&

.SHORT TERM (SAT-TUE)...11/925 PM.

***UPDATE***

The large spread of temperatures between inland valleys/deserts
and coastal areas is expected to continue tomorrow. Onshore
gradients will increase further tomorrow, with the LAX-DAG
gradient reaching 7 MB in the afternoon. Additionally a weak
upper level ridge will build over the region warming the airmass
aloft. The warmer upper level temperatures combined with strong
onshore flow, will keep marine layer clouds socked in at the
coasts, but warm inland areas, resulting in a slight amplification
the temperature spread across the region. Coastal areas will see
highs similar to today (in the 60s) and inland valleys and
deserts will warm to the the upper 80s to low 90s.

Besides the adjustments to temperatures, the main update is the
addition of slight thunderstorm chances for the Ventura County
mountains tomorrow afternoon. A weak shortwave through moving
through the upper level ridge will trigger sufficient lift for a
shower or thunderstorm.


***From Previous Discussion***

The overall pattern is not expected to change much over the next
several days. The weak high tonight might briefly lower the marine
layer depth somewhat but low cloud coverage should be similar to
the last few nights, except maybe not quite as far inland.
Clearing should be a little earlier Sunday for valleys, but not
for most coastal areas. This should lead to slight warming inland
but similarly cool at the coast.

Weak low pressure returns late Monday and Tuesday leading to a
deeper and later clearing stratus layer and cooler temps.
Increasing onshore flow will generate a stronger sea breeze,
especially through the mountain passes and Antelope Valley. There
is a small chance (around 10%) that the upper low will generate
enough instability Tuesday to create some afternoon buildups over
the mountains and perhaps an isolated shower or storm.

.LONG TERM (WED-SAT)...11/204 PM.

Onshore flow peaks Wednesday creating gusty winds for some
interior areas. Otherwise, the upper low will start to move east
later Wednesday into Thursday and be replaced by weak ridging
Friday/Saturday. This won`t have much impact overall on the local
weather as temperatures in most areas will change very little and
remain near to slightly below normal. A moderate to strong
onshore flow will maintain a solid marine layer along the coast
pushing into most coastal valleys overnight.

&&

.AVIATION...12/0200Z.

At 0038Z at KLAX, the marine layer was 1400 feet deep. The top of
the inversion was at 2700 feet with a max temperature of 21 C.

Moderate confidence in TAFs. Tonight cigs will be similar to the
last night, with increased chances of LIFR cigs for coasts and
valleys. Occasional vsby restrictions with fog and drizzle will
continue through at least Sunday morning. Flight cat transitions
may be off by +/- 2 hours.

KLAX...Moderate confidence in TAF. There is a 30% chc of a few
hours of VFR conds 22Z Sun - 01Z Mon. No significant easterly
wind component is expected.

KBUR...Moderate-to-high confidence in TAF, cigs are expected to
range from OVC004-OVC007. High confidence in clearing around 17Z
Sun.

&&

.MARINE...11/912 PM.

For the waters southwest through southwest of the Channel Islands
and the nearshore waters along the Central Coast, there is a 60-80
percent chance of Small Craft Advisory (SCA) winds from Point
Arguello south to San Nicolas Island late tonight and again Sunday
evening and night, decreasing to a 50-70 percent chance Monday
evening and night. Otherwise, SCA conditions are not expected
through Thursday over the Outer Waters.

Inside the southern California bight, there is 30-40 percent
chance of SCA winds Sunday night through Monday night. Otherwise,
winds and seas are expected to remain below SCA levels.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for
      zones 673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 5 PM Sunday to 5 AM PDT
      Monday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Schoenfeld/Hall
AVIATION...Schoenfeld
MARINE...Hall
SYNOPSIS...Hall

weather.gov/losangeles

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