276
FXUS66 KLOX 221746
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1046 AM PDT Sun Sep 22 2024

.SYNOPSIS...22/342 AM.

A warmer and drier pattern will establish through Monday as high
pressure aloft builds over the region. A warmer air mass will
likely remain in place through much of the week away from the
coast, with the hottest daytime temperatures forecast for Monday.
Onshore flow will persist through the period, maintaining night
through morning low clouds and fog for coastal areas and some of
the valleys.

&&

.SHORT TERM (TDY-TUE)...22/920 AM.

***UPDATE***

The marine inversion this morning ranged from 1400 ft deep at VBG
and around 1800 ft deep at LAX. Low clouds and fog covered the
coast and into some of the adjacent vlys thru mid morning. The low
clouds are expected to clear back to or off the coast by midday
with some low clouds possibly lingering along the Central Coast
beaches this afternoon. Elsewhere and otherwise, mostly sunny
skies will prevail across the region today. Breezy onshore winds
are expected this afternoon as well.

Temps this afternoon will be a few degrees below normal for the
coast and adjacent vlys, and a few degrees above normal for the
interior vlys, mtns and deserts. Much of the inland coast and vlys
should reach the 70s and 80s today, except the warmest vlys will
likely reach into lower 90s.

***From Previous Discussion***

584 dam hgts will persist through Tuesday as a weak high hgt upper
pinches off and retrogrades a 100 miles west of Pt Conception. The
weak sfc reflection of the low will help bring offshore trends
and even weak offshore flow in the morning hours to the area esp
Monday.

Offshore trends will continue on Monday and there will be less
marine layer clouds and an even quicker burn off. This will allow
for another 3 to 6 degrees of warming. Monday will be the warmest
day of the next 7 with max temps 3 to 6 degrees above normal.

A slight increase in onshore flow and a slight decrease in hgts is
expected Tuesday. This will cool temperatures a couple degrees
across coast and valleys but either little change or slight
warming across the interior.

.LONG TERM (WED-SAT)...22/330 AM.

Not much excitement on tap in the extended period. The faster more
dynamic flow will be well to north and there will be weak flow
over Srn CA. Gradients Wed to Fri to the east will increase to
moderate but the N/S grads will remain weak and may even be
slightly offshore in the morning hours. There will be better
onshore trends on Saturday. The night through morning low clouds
pattern will continue over the coasts will local penetration into
the lower vlys (esp the Santa Ynez Vly).

Look for 3 to 5 degrees of cooling Wednesday with the increase in
onshore flow. Thursday`s temps will be very similar to Wed`s.
Perhaps some barely noticeable warming Friday and then 2 to 3
degrees of cooling on Saturday as there is another noticeable
increase in the onshore flow both to the north and east.

In general max temps will be above normal across the interior but
a few degrees blo normal across the coasts and vlys.

&&

.AVIATION...22/1745Z.

Around 1636Z, the marine layer depth was around 1700 feet deep at
KLAX. The top of the marine inversion was around 4100 feet with a
temperature near 23 degrees Celsius.

High confidence in TAFs for KPRB, KPMD, and KWJF. There is a 10%
chance for VLIFR-LIFR cigs/vsbys at KPRB between 10Z and 15Z.

Low confidence in KBUR and KVNY. There is a 40% chance cigs do not
reach, and VFR conds prevail. Otherwise, VLIFR-LIFR conds are
slightly more likely.

Low confidence in LA coastal TAFs. There is a 10% chance for
VLIFR conds at KLAX/KSMO between 04Z and 15Z. However, there is
also a 10% chance that conds remain IFR-MVFR during this period.

Low confidence in remaining coastal TAFs north of LA county. There
is a 30% chance cigs don`t burn off at KSBA today. There is a 40%
chance of VLIFR conds at KSMX and a 30% chance at KSBP. At other
sites, minimum flight cat may be off by one cat at any point after
cigs arrive.

Arrival of cigs may be off by +/- 4 hours from current forecast at
all sites with cigs in TAFs, with greatest uncertainty south of Pt
Conception.

KLAX...Low confidence in TAF due to uncertainty in arrival time
and cat of cigs. There is a 30% chance of cigs arrive as early as
00Z or as late as 04Z. There is also a 10% chance for cigs
OVC001-OVC002 between 04Z and 15Z, and a 10% chance of cigs
remaining OVC005 or higher during this period. There is a 30%
chance for MVFR conds by 18Z.

KBUR...Low confidence in TAF. There is a 40% chance cigs don`t
reach KBUR, and VFR conds prevail thru the period. If cigs do
arrive, there is a 30% chance for cigs OVC001-OVC002 and/or vsbys
1/2SM or lower.

&&

.MARINE...22/911 AM.

High confidence in the current forecast through Wednesday, then
moderate confidence thereafter. Winds and seas will remain below
Small Craft Advisory (SCA) levels through at least Wednesday,
except for 30-50% chance of local SCA level wind gusts near Pt
Conception and the San Pedro Channel this afternoon thru evening.
There is also a 20-30% chance of SCA level winds for the inner
waters off the LA and OC Coasts in the afternoon thru evening
Wednesday. Then, moderate to high confidence in winds and seas
increasing to SCA level Thursday thru Friday, with highest
confidence in the Outer Waters (Central Coast south to San Nicolas
Island) Friday.

&&

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

&&

$$

PUBLIC...Rorke/Sirard
AVIATION...Lewis
MARINE...Lewis/Hall
SYNOPSIS...Smith/Hall

weather.gov/losangeles

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