April 27, 2018
Temp
 
55.2 °F
 
Dew Pt.
 
50.8 °F
 
Humidity
 
85%
 
Pressure
 
1015.7 hPa 
  steady
Wind
 
0.0 mph 
    WSW
Rain
 
0.00 in 
  0.00 in/hr
UV index
 
---  
 
Solar rad.
 
100 W/m²
 
Overnight

Overnight: Patchy fog.  Otherwise, mostly cloudy, with a low around 54. Calm wind.
Patchy Fog
Friday

Friday: Patchy fog before 11am.  Otherwise, mostly cloudy, then gradually becoming sunny, with a high near 75. Light south wind becoming southwest 5 to 10 mph in the afternoon.
Patchy Fog
then Sunny
Lo 54 °F Hi 75 °F
000
FXUS66 KLOX 270340
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
840 PM PDT Thu Apr 26 2018

.SYNOPSIS...26/504 PM.

A trough of low pressure will gradually move across the West
Coast through Saturday, bringing cooler temperatures and partly
cloudy skies to the area along with areas of night and morning low
clouds and fog for the coast and valleys. Additionally, there
will be the potential for gusty west to northwest winds Friday
through Monday. On Tuesday, low pressure will move over the area,
resulting in the potential for some light precipitation to parts
of the region.

&&

.SHORT TERM (THU-SUN)...26/836 PM.

The marine inversion early this evening ranged from near 1400 ft
deep at LAX to near 2000 ft deep at VBG. Low clouds were noted
along the Central Coast this evening, with patchy low clouds along
the VTU/L.A. County coastal areas. The low clouds are expected to
expand overnight to much of the coast and adjacent vlys, while
the S coast of SBA County should remain largely free of the low
clouds due to some northerly sub-advisory level canyon winds. Low
clouds are also expected to develop in the SLO County interior
valleys later tonight, especially around the Salinas River Valley.
Otherwise, mostly clear skies will prevail across the forecast
area thru the night. Some advisory-level gusty W to SW winds will
continue across portions of the Antelope Valley this evening as
well, especially western areas and in the foothills around Lake
Palmdale. A Wind Advisory is in effect for these areas thru 10 PM
this evening.

An upper level low over the E Pac will move ENE toward the nrn
CA/Oregon coast tonight thru Fri night, then move into Oregon on
Sat before meandering about over the Pac NW thru Sun. A shortwave
upper level trof along the southern fringes of the upper low will
move into central and srn CA on Sun.

Northerly pressure gradients are forecast to increase thru Fri and
continue thru the weekend, with gusty NW to N winds expected to
develop for the L.A./VTU County mtns especially along the I-5
corridor, as well as the SBA County S coast and mtns where
advisory level wind gusts will be possible each evening at least
thru Sat. Gusty NW to W winds will continue across the Antelope
Vly as well, with some advisory-level gusts also possible in the
afternoon and evenings at least thru Sat. For the Central Coast,
gusty winds to advisory levels also cannot be ruled out each
afternoon and evening thru Sat.

It looks like the northerly flow will disrupt the marine layer
pattern for SLO/SBA/VTU Counties Fri night and thru the weekend, so
the only low clouds are expected along the L.A. County coast and
some adjacent vlys night and morning hours. There should also be
some clouds banked up on the N mtn slopes and possibly over
interior SLO County toward the Kern County border and over the
Cuyama Vly at times Sat thru Sun. Otherwise, mostly clear skies
can be expected over the forecast area thru the period.

Temps Fri thru Sun are expected to be near normal to slightly below
normal for the most part. Highs in the vlys should reach the low to
mid 70s each day, with coastal areas expected to be in the 60s to
around 70.

.LONG TERM (MON-THU)...26/159 PM.

Models in general synoptic agreement through the extended period.
At upper levels, another low spins off of the pattern on Monday
near the California-Oregon border and the trough/low will move
over the area on Tuesday then into Arizona on Wednesday.

Monday looks similar to Sunday. Main concern will continue to be
the potential for advisory-level Sundowner winds across southern
Santa Barbara county. There will likely be fewer coastal clouds on
Monday and skies should remain mostly clear with temperatures a
couple degrees below seasonal normals.

On Tuesday, things become more unsettled as trough/upper low moves
across the area. At this time, the GFS has a closed upper low
just off the Central Coast around noon on Tuesday while the EC has
a broader but deeper trough. Both models continue to show some
light precipitation (0.1-0.25 inches) across the area on Tuesday.
Have placed the greatest (but still not great) chance of showers
over LA County for now, but wouldn`t be surprised to see this
extend over whole CWA in the next couple of days if the GFS
forecast is accurate. The NBM has about 10-15 POP throughout the
CWA and agreed with its greater threat in LA County, so leaned
that way.

On Wednesday, the upper low/trough should have moved far enough
east to keep any precipitation away from our CWA. Clouds will
clear and temperatures will begin to rebound a bit.

By Thursday the 500MB heights will be back to around 580DM where
they are today. Lighter onshore conditions should have it a bit
warmer than today heading into the end of next week

&&

.AVIATION...27/0001Z.

At 2323Z at KLAX, the marine layer was near 1000 feet deep. The top
of the inversion was near 2100 feet with a temperature around 16
deg C.

Moderate confidence overall in the 00Z TAFs. A marine layer pattern
with low clouds and IFR/MVFR cigs is expected for much of the coast
and adjacent vly airfields tonight and Fri morning. Low clouds are
forecast to develop between 02Z at KSMO and KLAX to 0830Z at KVNY,
then clear to VFR between late Fri morning to early Fri afternoon,
with the latest clearing expected at KOXR around 21Z Fri afternoon.
The timing of the onset and clearing of the low clouds could be off
+/- an hour or two.

For KPRB, there should be a period of low clouds and mostly LIFR/IFR
cigs from about 05Z-1730Z as well. Otherwise, VFR conditions can be
expected thru Fri afternoon.

For KSBA, some northerly canyon winds in the vicinity tonight into
Fri morning should help to keep low clouds away from the airfield
thru Fri afternoon, with VFR conditions expected during the period.
However, there is still a 20% chance of low clouds and IFR or MVFR
cigs at the airfield early to mid Fri morning.

For KWJF and KPMD, hi confidence in the 00Z TAFs with VFR conditions
through Fri afternoon. Gusty SW to W winds can also be expected
for much of the TAF period.

KLAX...Moderate confidence overall in the 00Z TAF. Low clouds with
MVFR cigs are expected from about 02Z-20Z tonight and Fri, with VFR
conditions for the rest of the afternoon and evening. The timing of
the onset and clearing of the low clouds could be off +/- an hour or
two.

KBUR...Moderate confidence overall in the 00Z TAF. Low clouds with
MVFR cigs are expected from about 08Z-18Z tonight and Fri morning,
with VFR conditions for the rest of the time. The timing of the
onset and clearing of the low clouds could be off +/- an hour or two.

&&

.MARINE...26/839 PM.

High confidence that winds will increase to SCA (Small Craft
Advisory) levels across the outer waters tonight. Winds will
likely continue at or above SCA levels across the outer waters
thru Mon. There is a 50% chance that winds will increase to Gale
Force across the southern two thirds of the outer waters zones
(PZZ673 and PZZ676) as early as Fri afternoon, with winds possibly
continuing at Gale Force levels at times thru Sun night.

Across the inner waters north of Pt Conception, there is a 20%
chance of SCA level winds this evening. There is a 40-50% chance
of SCA level winds Fri afternoon and evening, then SCA level winds
are likely Sat afternoon through Mon.

For the inner waters south of Pt Conception...there is a 20%
chance of SCA level winds across western portions of the SBA
Channel this evening. SCA winds are likely, especially across
western portions of the zones during the afternoon and evening
hours Fri thru Mon.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 10 PM PDT this evening for zone
      59. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Monday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT Friday for
      zones 673-676. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through late
      Sunday night for zones 673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (SUN-THU).

There will be potential gale force winds mainly for the outer
coastal waters during the outlook period.

&&

$$

PUBLIC...Sirard/jld
AVIATION...Sirard
MARINE...DB/CK/Sirard
SYNOPSIS...JLL/Sirard

weather.gov/losangeles

NWS LOX Office Area Forecast Discussion