857
FXUS66 KLOX 221043
AFDLOX

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

Updated aviation section and synopsis

.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)...22/313 AM.

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.

Currently the marine layer has been smooshed down to 1200 ft
which is still deep enough to bring low clouds to the lower vlys
(a stratus surge down the Salinas River Vly has also brought low
clouds to the Paso Robles area). Low clouds also cover all of the
coasts. Clearing should be quicker and more complete today due to
the offshore trends. The beaches will warm a few degrees today.
Away from the beaches, however, there will be about 6 degrees of
warming further inland and 8 to 12 degrees in the vlys.

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...22/1040Z.

Around 0715Z, the marine layer depth was around 1200 feet deep at
KLAX. The top of the marine inversion was around 2100 feet with a
temperature near 18 degrees Celsius. There was another inversion
above up to around 4100 feet.

High confidence in the current forecast for desert terminals,
otherwise moderate confidence in all other terminals. Higher
confidence in flight categories. Less confidence in timing. LIFR
to IFR conditions at terminals north of Point Conception and IFR
to MVFR conditions will continue at terminals south of Point
Conception through at least 16Z. Timing of clearing could off by
up to four hours. There is a moderate chance of LIFR conditions
at terminals north of Point Conception through 14Z. Farther to the
south, there is a low-to-moderate chance of VFR conditions
continuing at Los Angeles County valley terminals. There is a
high-to-likely chance of LIFR to IFR conditions returning tonight
and into Monday morning.

KLAX...IFR to MVFR conditions will continue through at least 20Z,
and possibly as late as 23Z. There is a 20 percent chance that
KLAX may not clear at all. A return of IFR to MVFR conditions
could occur as soon as 01Z or as late as 03Z. Higher confidence
exists in IFR conditions after 03Z.

KBUR...There is a 20 percent of VFR conditions continuing through
the period, otherwise IFR to MVFR conditions will spread into KBUR
as soon as 1130Z, or as late as 13Z. VFR conditions will develop
between 16Z and 17Z.

&&

.MARINE...22/259 AM.

High confidence in the current forecast through Thursday, then
moderate confidence thereafter. Winds and seas will remain below
Small Craft Advisory (SCA) levels through at least Thursday,
except for a moderate-to-high (30-50 percent) chance of SCA level
winds this afternoon and evening. The highest chances of SCA
levels this afternoon and evening will be for an area in the
vicinity of Point Conception. On Thursday afternoon, there is a
high (40-50 percent) chance of SCA levels winds for the waters
beyond 10 NM offshore along the Central Coast southeast to San
Nicolas Island.

&&

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

&&

$$

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

weather.gov/losangeles

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