507
FXUS66 KLOX 241718
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1018 AM PDT Tue Sep 24 2024

.SYNOPSIS...24/934 AM.

Low clouds and fog will continue across coastal areas through the
week with some afternoon clearing and below normal temperatures.
Valley temperatures will begin a cool down today be at or below
normal the rest of the week. Far interior areas will remain above
normal. Otherwise, a quiet weather pattern will continue.

&&

.SHORT TERM (TDY-THU)...24/944 AM.

***UPDATE***

A solid coastal marine layer, about 1700 feet deep in LA County
sloping down to around 1100 feet along the Central Coast, is
making late September feel more like mid June. This will be a
quiet week of weather with below normal temperatures across coast
and valleys, but several degrees above normal in the Antelope
Valley. A weak but stubborn upper low will linger just a few
hundred miles west of the coast, maintaining a weak cyclonic flow
aloft that will provide a favorable pattern for stratus
development. This pattern may continue well into next week with
very little day to day changes in temperatures as well.

***From Previous Discussion***

An unexpected eddy spun up just before midnight and has lifted
the marine layer a few hundred feet enough to bring plenty of low
clouds to the vlys and also to eliminate most of the dense fog.
The deeper marine air intrusion will also bring noticeable cooling
to the vlys. Low clouds will hug the coast and many beaches will
remain cloudy all day.

Not much change in the cloud pattern for Wed and Thu skies will
be clear save for the night through morning low clouds which will
extend into the vlys. Hgts will fall through the two day period
as a long wave trof develops in the east pac and moves closer to
the coast. Look for 2 to 4 degrees of cooling Wed and 1 to 2
degrees on Thu. Max temps will take on an early July like
distribution with the interior sections running 4 to 8 degrees
above normal and the csts and vlys (swaddled in marine air) will
end up 3 to 6 degrees below normal.

.LONG TERM (FRI-MON)...24/327 AM.

The benign weather will continue late this week and into the
weekend. Hgts rise a few dam on Friday as a weak upper high pushes
into the state from the east. Look for 2 to 4 degrees of warming
across the board.

A cooling trend will develop on Saturday and continue into Sunday
as troffing spreads over the state and onshore flow increases. The
night through morning low clouds will penetrate a little deeper
into the vlys and will persist a little longer at the beaches.
There will be stronger afternoon west winds across the mtns and
the Antelope Vly. Look for 2 to 4 degrees of cooling on Saturday
and 1 to 2 degrees on Sunday. The csts/vlys will end up 4 to 8
degrees below normal while the interior will remain 3 to 6 degrees
above normal.

Not the best confidence in the forecast for early next week but
the most likely scenario is for high pressure to move closer to
the state from the east and kicking off a slow warming trend.

&&

.AVIATION...24/1717Z.

At 1609Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was near 4100 ft with a temperature of 26 deg C.

High confidence in TAFs for KPRB, KPMD, and KVNY. There is a 10%
chance for LIFR-IFR cigs at KPRB between 08Z and 15Z.

Low confidence in LA County coastal and valley TAFs. There is a
30% chance KLAX/KSMO briefly become VFR between 19Z and 00Z.
There is a 10% chance for VLIFR cigs/vsbys between 02Z and 15Z.
There is also a 20% chance that conds remain IFR or higher thru
the period. There is a 20% chance KBUR and KVNY remain VFR thru
the period, there is also a 30% chance KBUR and/or KVNY become
LIFR due to cigs and/or vsbys between 04Z and 15Z.

Low confidence in remaining TAFS. There is a chance KSMX (40%)
and KSBP (20%) become VLIFR between 02Z and 15Z. KSBA, KOXR, and
KCMA all have a 10% chance for VLIFR conds during the same
period.

At all sites with cigs, minimum flight cat may frequently bounce
around tonight and the arrival time of cigs may be off by +/- 3
hours.

KLAX...Low confidence in TAF. There is a 30% chance for brief VFR
conditions between 19Z and 00Z. There is a 10% chance for
VV001-VV002 cigs and/or vsbys 1/2SM or lower between 02Z and 15Z.
However, there is also a 20% chance for cigs to remain OVC005 or
higher thru the period. High confidence in no significant east
wind component.

KBUR...Low confidence in TAF. There is 20% chance for VFR conds
thru the entire period, there is also a 30% chance for cigs
OVC002-005 and/or vsbys 1SM or lower between 04Z and 15Z if cigs
arrive.

&&

.MARINE...24/850 AM.

For the Outer Waters (Central Coast south to San Nicolas Island),
moderate to high confidence in the forceast. High confidence in
the northern zone (10 to 60 NM off the Central Coast) remaining
below Small Craft Advisory (SCA) level thru Thursday, then there
is a 40-50% chance of SCA winds and seas Thurs afternoon thru
evening. In the two Southern Zones (Pt Sal to San Nicolas
Islands), moderate confidence in conditions remaining sub advisory
level thru tomorrow afternoon, then there is a 40-60% chance of
SCA level winds form Pt Conception to San Nicolas Island in the
afternoon thru evening tomorrow and Thurs. Then, moderate
confidence in the Outer Waters remaining sub advisory Friday thru
the weekend.

For the Inner Waters along the Central Coast, high confidence in
conditions remaining sub advisory level thru the period, with
highest chances (20-30%) of SCA conditions Thurs afternoon thru
evening.

For the Inner Waters south of Pt Conception, moderate confidence
in winds and seas remaining below SCA level thru tomorrow morning.
Local gusts to 25 kt are possible (20-30%) this afternoon thru
evening in the Santa Barbara Channel and from Anacapa Island to Pt
Dume. Higher confidence in more widespread SCA level winds in this
area and the San Pedro Channel tomorrow afternoon thru evening.
Then, moderate confidence in winds remaining sub advisory thru the
weekend.

A shallow marine layer will bring at least patchy dense fog thru
tomorrow, especially in the afternoon thru evening hours. Please
refer to our marine weather statement for more information.

&&

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

&&

$$

PUBLIC...MW/Rorke
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...MW

weather.gov/losangeles

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