327
FXUS66 KLOX 211018
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
318 AM PDT Tue May 21 2024

.SYNOPSIS...21/231 AM.

Low clouds will continue through the morning with better clearing
this afternoon. More sunshine with slight warming is expected
today and Wednesday as onshore flow weakens. Then cooler with
increasing marine layer clouds again the latter half of next week.

&&

.SHORT TERM (TDY-THU)...21/302 AM.

Broad scale pos tilt troffing will cover the state and most of the
western CONUS through the next three days. Good offshore trends
will make today the day with the weakest onshore flow. Onshore
flow will increase both Wed and Thu esp in the W to E direction.

Today will likely be the sunniest day due to the weaker onshore
flow and a very weak marine layer capping inversion. Decent N to S
flow across SBA county will keep the south coast cloud free. It
is likely that most of the area will see sunshine in the afternoon
and the evening will also likely be clear for most of the air.
Rising hgts, extra sunshine and weaker seabreezes will all add up
to a noticeably warmer day (4 to 8 locally 10 degrees). Despite
this warming max temps will come in 4 to 8 degrees blo normal.

Clouds will be slower to form tonight but by dawn most of the
coasts and vlys should be covered with stratus. Clearing will
likely be a little slower but almost all of the area will see
sunshine in the afternoon. Higher hgts will bring continued
warming to the interior but the stronger seabreeze will cool the
coasts and to a lesser degree the vlys.

The troffing will be a little more vigorous on Thursday and the
onshore flow will increase to near 9 mb w to e. Look for the
return of a deep vly penetrating marine layer stratus field with
slow to no clearing. Max temps will fall 3 to 6 degrees and will
end up mostly in the mid 60s to lower 70s across the coasts and
vlys. The interior will end up upper 70s and to mid 80s.

.LONG TERM (FRI-MON)...21/317 AM.

For the extended, models and their respective ensembles are in
decent agreement through the period. The broad upper level trof
will continue over the area Fri/Sat. On Sun/Mon weak ridge will
move into the state.

On Fri/Sat look for a May Grey pattern with total marine layer
stratus coverage over the csts/vly and xtnding into the mtn
passes. Clearing will be slow across the vlys and interior coastal
sections while most of the coastlines will remain mired in the low
clouds. The moderate to strong onshore gradients will likely
produce some advisory level westerly winds across interior
sections each afternoon and early evening, especially in the
Antelope Valley foothills.

For Sunday/Monday, increasing heights will smoosh the marine
layer down which will decrease the inland penetration. Also with
rising thicknesses and less marine influence, a warming trend can
be expected for all areas except right at the beaches.

&&

.AVIATION...21/0713Z.

At 0505Z at KLAX, the marine layer was 3200 ft deep. The top of
the inversion was at 4800 feet with a temperature of 13 C.

Good confidence in desert TAFs.

Low confidence in TAF for KSBA with a 40 percent chc of MVFR cigs
11Z-18Z.

Moderate confidence in TAFs. VFR transitions could be off by +/-
90 minutes. Lower confidence in return of low clouds after 22/03Z
with near equal chances of an earlier or much later arrival time.

KLAX...Moderate confidence in TAF. VFR transition could occur any
time between 18Z and 21Z. Low confidence in timing of return of
low clouds Tuesday evening with a 30 percent chc of an arrival
time 10Z-11Z and a 20 percent chc of 07Z-08Z. Good confidence that
any east wind component will be 5 knots or less.

KBUR...Moderate confidence in TAF. VFR transition may be as late
as 20Z. There is a 30 percent chc that cigs will not drop below
OVC022. There is a 25 percent chc of no low clouds Tuesday
evening.

&&

.MARINE...20/932 PM.

High confidence in the current forecast. Widespread Small Craft
Advisory (SCA) conditions (winds and seas) will continue over the
offshore waters from the Central Coast to San Nicolas Island
through at least late Tuesday night and likely through at least
Friday. There will likely be brief and slight lulls during the
late night and morning hours. There is a 30-50 percent chance of
SCA winds for the western Santa Barbara Channel and into the
nearshore waters along the Central Coast each afternoon and
evening. SCA conditions are unlikely elsewhere.

A long period south to southwest swell will diminish late Tuesday
night and into Wednesday. This will create larger than usual
breaking waves nearshore as well as some stronger currents near
most harbor entrances.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect through Wednesday afternoon
      for zones 87-362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Friday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...Hall
SYNOPSIS...Gomberg

weather.gov/losangeles

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