504
FXUS66 KLOX 231015
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
315 AM PDT Mon Sep 23 2024

.SYNOPSIS...23/227 AM.

It will be a warm day inland today but the marine layer will keep
the coasts and lower valleys a little cooler. A warm air mass
will remain in place through much of the week keeping above normal
temperatures going across the interior. The marine layer will
continue to bring cooler weather to the coasts. Mostly clear
skies can be expected through the period except for night and
morning coastal low clouds and fog.

&&

.SHORT TERM (TDY-WED)...23/259 AM.

The marine layer remains 1100 ft deep. Marine layer stratus pushed
ashore by weak onshore flow both to the N and E covers all of the
coasts and some of the lower vlys. 1 to 2 mb of offshore trends
will allow for slightly quicker clearing today with most areas
becoming sunny by noon. The offshore trends and warm airmass aloft
will combine to bring 5 to 10 degrees of warming to the csts/vlys.
The interior which saw its big jump in temps ydy will warm 2 to 5
degrees. Today will be the warmest day of the next 7 for the
csts/vlys with max temps away from the beaches 3 to 6 degrees
above normal.

The marine layer will be a little shallower tonight and there will
be a little less clouds in the vlys. The csts, however, will
remain mired in stratus with patchy dense fog.

Not much excitement in the Tue/Wed fcst. At the upper levels SW
flow will develop over the state as a trof forms in the E PAC and
a high amplitude ridge develops over the Rockies. Tuesday`s 586
dam hgts will fall to 584 dam. There will be similar gradients
Tuesday and a stronger onshore push to the east on Wed.

The low cloud pattern will continue across the coasts each night
through morning with a little more vly penetration on Wed due to
the increase in onshore flow.

There will not be too much change in temps on Tuesday. The
interior will warm a little making Tuesday the warmest day there.
Most coastal areas will cool a degree or two. The lowering hgts
and increased onshore flow will combine to bring 3 to 6 degrees of
cooling to the area on Wednesday. The marine layer will bring a
split personality to temps on Wed with the csts/vlys 2 to 4
degrees blo normal and the interior 4 to 6 degrees above normal.

.LONG TERM (THU-SUN)...23/313 AM.

The GFS and EC ensembles and deterministic runs are in good
agreement thru the xtnd period. Srn CA will be in between high
pressure to the east and low pressure troffing to the west. SW
flow aloft will continue through the period.

Quiet weather will dominate the fcst. In fact it will be rather
June like with the forecast confined to how much marine layer
stratus there will be each night through morning.

Those low clouds should cover the coasts each night through
morning with perhaps a little better vly coverage Sunday as the
onshore flow is forecast to increase to mdt-stg.

Look for slight warming Thu and better warming Fri. Cooling is on
tap for both days Sat and Sun. Max temps will continue cooler than
normal across the csts/vlys and warmer than normal across the
interior.

&&

.AVIATION...23/0638Z.

At 0515Z at KLAX, the marine layer was 1100 feet deep. The top of
the inversion was 2600 feet with a temperature of 23 degrees C.

High confidence in TAFs for KPRB, KPMD, and KWJF.

Good confidence in KBUR and KVNY. There is a 15% chance of LIFR
conds 12Z-15Z.

Moderate confidence in coastal TAFs. VIS will likely vary
frequently but LIFR cigs will hold steady. There is 30 percent
chance that cigs will linger an hour or two later than fcst. Low
clouds may also return 2 hours earlier than fcst Monday evening.

KLAX...Moderate confidence in TAF. Vis will likely vary frequently
through 15Z and TAF will reflect the sfc vsby not the tall tower
vsby. There is a 20 percent chc that VFR conds will arrive at 18Z
and another 20 percent chc that it will be delayed until 21Z. Cigs
Monday even could arrive as early as 02Z. Good confidence in no
significant east wind component through the period.

KBUR...Good confidence in TAF with only a 15 percent chc of OVC004
conds 12Z-15Z.

&&

.MARINE...23/315 AM.

High confidence in the current forecast through early Thursday,
then moderate confidence thereafter. Winds and seas will remain
below Small Craft Advisory (SCA) levels through early Thursday,
except for low-to-moderate (20-30) percent chance of local SCA
level wind gusts in the vicinity Point Conception, near Point Dume
and into the San Pedro Channel each afternoon and evening through
Wednesday. Winds and seas will increase to SCA levels between
Thursday afternoon and late Friday night. There is a high (40-50
percent) chance of SCA conditions for the waters beyond 10 NM
offshore along the Central Coast southeast to San Nicolas Island.

A shallow marine layer depth over the coastal waters will bring at
least patchy dense fog to the coastal waters at times through
Wednesday morning. A marine weather statement is in effect through
noon today, but there is a likely chance that areas to widespread
dense fog will redevelop over the coastal tonight through Tuesday
morning.

&&

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

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...Hall
SYNOPSIS...Sirard

weather.gov/losangeles

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