610
FXUS66 KLOX 121754 AAA
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1054 AM PDT Mon Aug 12 2024

updated aviation discussion

.SYNOPSIS...12/326 AM.

A trough of lower pressure extending down the California coast
will bring a slight cooling trend through most of this week.
Skies will be mostly clear away from the immediate coast, which
will see overnight and morning marine stratus.

&&

.SHORT TERM (TDY-WED)...12/929 AM.

***UPDATE***

Forecast adjusted for low clouds, but otherwise on track. Weather
related impacts continue to look minimal through at least the
weekend with mainly subtle day to day changes.

***From Previous Discussion***

Once again this morning, low clouds were widespread on the Central
Coast, but unlike on Sun, clouds have pushed into the Santa Ynez
Valley as well. S of Pt. Conception, there was an area of low
clouds southwest of L.A. County, and some clouds should push into
the beaches by daybreak. There is a slight chance that some
stratus will form in place across coastal sections of Ventura
County. Expect any low clouds to clear by mid morning, except
possibly late morning to around noon on the Central Coast beaches.

W-E pressure gradients have become more strongly onshore, while
N-S gradients were still weakly offshore across SBA County, and
weakly onshore farther to the east. There will be some gusty
winds in the Antelope Valley and through the Highway 14 Corridor
this afternoon, but winds should remain below advisory levels.
The upper high that was parked over the region during this past
weekend will weaken and shift southward today as a broad upper
trough moves into the West Coast. With height falls, cooling at
950 mb and stronger onshore gradients, expect some cooling in most
areas today. In the hottest part of the Antelope Valley and some
of the hotter valleys west of the mountains, highs should top out
in the mid 90s to near 100 degrees, fairly close to normal.

The upper trough will linger across CA tonight and Tue, then upper
level high pressure will build into the forecast area from the
southwest. Moderate onshore pressure gradients from W to E will
keep gusty winds each afternoon and evening across the Antelope
Valley and the Highway 14 Corridor through Wed. N-S gradients
across SBA County will increase gradually through Wed. There will
likely be some gusty NW winds each evening across southwestern
coastal sections of SBA County and the western Santa Ynez Range
each of the next three evenings. Winds should remain below
advisory levels today, but there will be an increasing chance
of winds reaching advisory level Tue evening and Wed evening.

The marine layer should deepen a bit tonight, and the models are
showing more in the way of low level moisture in coastal areas
tonight. Expect low clouds to become widespread across the
coastal plain tonight, and clouds could push into some lower
valley areas as well. N-S gradients across SBA County may decrease
low cloud coverage there Tue night and again Wed night. Max temps
should be down a couple of degrees in most areas Tue thanks to
height falls and cooling at 950 mb, then slight warming is likely
Wed as heights begin to rise.

.LONG TERM (THU-SUN)...12/504 AM.

Expect little change in the upper pattern Thu, with an upper high
centered over or just south of the forecast area. Night thru
morning stratus will be confined mostly to the coastal plain, with
clouds possibly pushing into the lower valleys. Max temps Thu
should be similar to those Wed in most areas. N-S gradients may
bring some gusty winds to southern SBA County Thu evening.

An upper low will approach the Pacific NW Thu night/Fri with a
trough extending southward into the region. Meanwhile, a strong
upper high will be located over New Mexico. This pattern will
change very little over the weekend. SW flow aloft should keep
monsoonal moisture to the east of the area thru the weekend. The
marine layer should deepen a bit, with widespread night/morning
low clouds and fog in coastal and some valley areas Fri thru Sun.
Max temps should fall a couple of degrees both Fri and Sat, with
temps slightly below normal in most areas over the weekend.

&&

.AVIATION...12/1752Z.

At 17Z at KLAX, the marine layer was 700 ft deep. The top of the
inversion was at about 1500 ft with a temperature of 24 C.

High confidence in the 18Z TAFs for KPRB, KSBA, KBUR, KVNY, KPMD,
and KWJF.

Moderate confidence in the rest of coastal 18Z TAFs. Timing of
low cloud arrival may be off by as much as three hours. There is a
30%-40% chance of LIFR conds at KSMX 08Z-17Z Tue. There is a 30%
chance of VFR conds persisting through the period for KSMO and
KLGB.

KLAX...Moderate confidence in the 18Z TAF. Return of cigs tonight
could be up to three hours earlier than fcst. High confidence in
no significant east wind component.

KBUR...High confidence in the 18Z TAF with VFR conds thru the
period.

&&

.MARINE...12/849 AM.

For the outer waters, Current forecast looks on track with Small
Craft Advisory level winds expected through Tuesday, with lower
confidence in SCA level winds for the waters south of the Channel
Islands. Winds appear to increase mid-week, with a 20 percent
chance for isolated gale force winds by Tuesday night. There is a
20-40 percent chance of GALES from Wednesday night into Friday.

For the inner waters north of Point Sal, there is a 30-50 percent
chance of SCA level winds during each afternoon into evening
hours through the week, with the highest chances Wednesday through
Friday. Additionally, there is a 30% chance for isolated gale
force gusts Wednesday and Thursday night.

For the inner waters south of Point Conception, there is a 30-50
percent chance of SCA conditions extending into western Santa
Barbara Channel during each afternoon into late evening hours,
especially for Thursday and Friday. Otherwise, conds will remain
below SCA levels through Friday night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB
AVIATION...Sirard
MARINE...Phillips/Lund/Sirard
SYNOPSIS...jld

weather.gov/losangeles

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