Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 031210
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
510 AM PDT Mon Aug 3 2020

.SYNOPSIS...03/327 AM.

There will not be much change in temperatures today from
yesterday. A cooling trend will start Tuesday and continue through
mid week before a warming trend that will start at the end of the
week. The night through morning low cloud regime will continue and
expand.

&&

.SHORT TERM (TDY-WED)...03/317 AM.

The marine layer is about 1100 ft deep south of Pt Conception and
around 700 ft over the Central Coast. A weak eddy has brought low
clouds to the csts south of Pt Conception and locally into the
vlys. There will be some dense fog in the vlys due to the
elevation rise. There is a little bit of a north push that
resulted from a trof passage across the north of the state. This
will allow for a few degrees of warming for the most of the area,
but esp the SBA south coast where the north flow will bring about
4 to 5 degrees of warming compared to ydy. While it will be a warm
day it will come in just under heat advisory levels. Have to
mention that there is a bit of uncertainty in the temperature
forecast near the coast/vly interface where there is a bit more
marine layer. This area could be quite a bit cooler than fcst. The
north to south gradients will be strongest across the western
half of SBA county. A wind advisory in effect from 3pm this
afternoon to 3am Tuesday morning for the SBA south coast and Santa
Ynez range with the strongest winds west of Goleta.

A trof moves into the state on Tuesday and expands on Wednesday.
Hgts fall, the marine layer will lift into the vlys and the
onshore flow will increase. All of these will combine to drop max
temps 4 to 8 degrees on Tue and another 3 to 6 degrees on Wed. Max
temps on Wed will be 4 to 8 degrees blo normal.

The increasing west to east flow will bring near advisory level
winds to the Antelope Vly and foothills each afternoon.

.LONG TERM (THU-SUN)...03/327 AM.

Low excitement levels for the extended period as the marine layer
seems to have lost all of its calenders and still thinks its June.
Broad west coast troffing will continue through Sunday, although
it will weaken and hgts will rise starting Friday. There will be
strong onshore flow each day esp from the west to the east.

The night through morning low cloud pattern will continue through
the week and into the weekend. The strong onshore flow will make
for slow clear and will keep some beaches cloudy all through the
afternoon. The marine cloud coverage will lessen over the vlys
over the weekend and hgts increase.

Temps Thursday will be similar to Wednesday perhaps a little
cooler over LA county. As hgts rise max temps away from the coast
will warm a little each day Fri-Sun.

There will likely be some gusty westerly winds during the afternoons
across the Antelope Valley and surrounding mountain areas. The
afternoon seabreezes will also be a little stronger than normal,
but otherwise not expecting any winds of note.

&&

.AVIATION...03/1208Z.

At 12Z at KLAX...the marine layer was around 1500 ft deep. The top
of the inversion was around 3500 ft with a temp of 28 degrees C.

Low clouds were fairly widespread in coastal areas south of Pt.
Conception, and have pushed into the lower valleys of VTU County.
Conds were mostly IFR to LIFR, except locally VLIFR across VTU
County. North of Pt. Conception, low clouds were patchy, mainly
affecting southern portions of the Central Coast and the Santa
Ynez Valley. Conds were mostly LIFR to VLIFR where there were
cigs. Expect skies to clear by mid morning, except possibly late
morning near the beaches.

Gusty west winds will affect the Antelope Valley this afternoon
and evening. Gusty NW winds will affect the I-5 Corridor through
late tonight and western portions of the Santa Ynez Range and
the adjacent south coast of SBA County tonight.

Expect widespread low clouds in coastal areas tonight, with the
exception of the south coast of SBA County due to areas of gusty
NW to N winds. N-S gradients should keep clouds out of the San
Fernando Valley.

KLAX...Moderate confidence in the 12Z TAF. There is a 20-30%
chance that cigs could linger to 16Z. There is a 20-30% chance
that cigs will arrive as early as 06Z this evening.

KBUR...High confidence in the current TAF. There is a 20% chance
of LIFR to IFR cig after 10Z tonight.

&&

.MARINE...03/419 AM.

Across the outer waters...Gale Force winds are expected to
develop from north to south in the northern two zones (PZZ670,673)
today, preceded by Small Craft Advisory level winds. Winds will
be strongest across western portions of the zones. Winds should
drop below Gale Force late tonight, then SCA level winds are
likely from late tonight thru late Wed night. There is a 40% chance
of SCA level winds Thu thru Fri. Across the southern zone (PZZ676),
SCA level winds are expected to develop today, strongest NW of
San Nicolas Island, then SCA level winds will continue thru late
Wed night. There is a 50% chance of SCA level winds Thu thru Fri.

Across the inner waters north of Pt. Sal, winds will increase to
SCA levels this afternoon and continue thru late tonight. There
will be a lull in the winds Tue morning, but SCA level winds are
expected Tue afternoon thru late Tue night. SCA level winds are
likely Wed afternoon and evening, There is a 30% chance of SCA
level winds Thu afternoon and evening.

Across the inner waters south of Pt. Conception...winds across
the western Santa Barbara Channel will reach SCA levels this
afternoon thru late tonight, and again Tue afternoon thru late
Tue night. SCA level winds are likely across western portions of
the SBA Channel Wed afternoon and evening, then there is a 30-40%
chance of SCA level winds there during the afternoon and evening
hours Thu and Fri. SCA conds are not expected across the
remainder of the inner waters south of Pt. Conception.

Patchy fog, locally dense with visibility down to one mile or
less, will affect the waters this morning.

&&

.FIRE WEATHER...02/338 PM.

A strong upper level high pressure system will continue to bring hot
temperatures, very low humidity, and locally breezy onshore winds
over interior sections through Monday resulting in elevated to brief
critical fire weather conditions. While coastal and coastal valley areas have
seen a few degrees of cooling today, Interior areas continue
to see high temperatures of 95 to 105 degrees on Monday. Minimum humidity
values will continue to mostly range between 5 and 15 percent across the
interior valleys, foothills, mountains, and deserts through Monday,
except locally down to 3 percent in the Antelope Valley on Monday.
In addition, many mountain and foothill locations will continue to
see poor overnight humidity recoveries in the teens and 20s, with
low temperatures as high as 80 degrees. West to north wind gusts
between 20 and 40 mph will continue through Monday night,
strongest over the Antelope Valley and Los Angeles county
mountains each afternoon, and over the I-5 Corridor and southern
Santa Barbara County each night. In addition, the hot, dry, and
unstable conditions combined with dry fuels will lead to an
increased risk of deep vertical plume development with existing
and new fire ignitions across the interior.

Localized northwest winds can be expected across Gaviota and
Refugio this evening. Sundowner winds are then expected to
increase in strength and areal coverage Monday evening and Tuesday
evening across western portions of the Santa Barbara south coast
and foothills, where wind gusts of 30 to 45 mph can be expected.
Isolated gusts up to 50 mph will be possible near Gaviota by
Tuesday evening. Meanwhile, humidities will generally be in the 20
to 40 percent range during the times of sundowner winds, except
locally falling into the upper teens across portions of the Santa
Ynez mountains and foothills. Widespread cooling and an increase
in humidity is expected for Tuesday through Thursday, including
improved overnight recovery. However, the increased onshore flow
will continue to bring gusty onshore winds to the mountains and
Antelope Valley through the period.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 3 PM this afternoon to 3 AM PDT
      Tuesday for zones 39-52. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Wednesday for zones 645-650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Tuesday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zone 673. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Tuesday for zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Thursday for
      zone 676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (WED-SUN).

Gusty winds are possible through the Highway 14 Corridor and the
Antelope Valley each afternoon and evening. The gusty winds will
create elevated fire danger.

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB
FIRE...Gomberg
SYNOPSIS...30

weather.gov/losangeles


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