Duarte Weather

000
FXUS66 KLOX 201414 AAA
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
714 AM PDT Sat Apr 20 2019

.SYNOPSIS...20/710 AM.

A deep marine layer will keep skies mostly cloudy today along with
below normal afternoon temperatures. Sunday will be a little
sunnier and warmer. Sunshine and warming temperatures return for
next week.

&&

.SHORT TERM (TDY-MON)...20/312 AM.

A little trof is exiting the SE portion of the state while a
larger trof is dropping into the north of the state. There is
between 5 and 7 MB of onshore flow both to the east and the north.
The trof and the strong winds across the outer waters have spun up
a good sized eddy. All of these things have combined to produce a
preview of June gloom. The marine layer has risen to 3000 feet and
will likely be at 4000 feet by late morning. Marine layer stratus
covers all of the coastal and vlys areas and even covers the lower
coastal slopes. The northern portion of the SLO interior vly is
also covered with stratus. The onshore flow to KDAG will peak at
about 9.5 MB this afternoon. This strong onshore flow in
conjunction with the eddy will preclude any clearing and today
will be mostly cloudy across the coasts and vlys. The lift from
the eddy will also produce a quite a bit of drizzle this morning.
The strong onshore flow will produce enhanced coastal sea breezes
and advisory level wind gusts across the Antelope Vly. Max temps
will plummet and most areas will see max temps 5 to 10 degrees
blo normal.

The 2nd upper trof will move through the areas tonight. It will
keep the marine layer stratus going across the coasts and most of
the vlys with the exception of the SBA south coast where north
winds should keep the low clouds away.

A slow moving inside slider will move down the CA/NV border on
Sunday. It will reduce the onshore gradients by about 3 MB. This
will help clear most of the marine layer stratus by late morning
or early afternoon. Max temperatures will bump up a little, but
will remain below normal.

The onshore flow to the east greatly diminishes Sunday night and
actual offshore flow develops from the north. This will reduce the
marine layer stratus coverage which should be confined to the LA
county coast and lower vlys as well as a little bit of the VTA
coast. The north winds will create some upslope clouds on the
north slopes on the Kern county line.

A ridge will build into the area on Monday. Skies will be clear
everywhere by noon. The rising hgts...offshore flow from the north
and late April sunshine will all combine to bring 5 to 10 degrees
of warming to the area.

.LONG TERM (TUE-FRI)...20/321 AM.

Synoptically a ridge will sit over the area Tuesday through
Thursday. The GFS and EC disagree on the Friday forecast with the
EC advertising weak cyclonic flow and the GFS with weak anti
cyclonic flow.

The best offshore flow will be Tuesday and there may be a need for
a few low end advisories. The offshore flow will eliminate the
stratus. The increased hgts and offshore flow will bring another 5
to 10 degrees of warming and max temps will be 4 to 8 degrees
above normal with plenty of readings in the mid and upper 80s.

Not too much change to the forecast for Wednesday. The offshore
flow will be weaker from the north and there will be onshore flow
to the east. The beaches will likely cool some but the rest of the
area will see similar temps or even a degree warmer.

Look for some cooling each day Thu and Fri as the ridge weakens.
The onshore flow increases enough to bring night through morning
stratus back to the immediate coasts. Max temps will still remain
above normal.

&&

.AVIATION...20/1016Z.

At 0928Z, the marine layer was around 1900 feet deep. The top of
the inversion was 4100 feet with a temperature of 14 degrees
Celsius.

Moderate confidence in 12z TAFs. Good confidence that cigs will
continue to rise from IFR to MVFR by mid morning. Timing could be
off by an hour or two. There will be patchy drizzle across the
coasts and valleys through 18Z. There is a 30 percent chc of SCT
conds at any terminal from 20Z- 02Z

Later this afternoon there will be strong southwesterly winds
across the deserts with a 20-30% chance of MVFR vsbys in blowing
dust and sand.

KLAX...Overall, moderate confidence in 12z TAF. Timing of flight
cat changes could be off by +/- 2 hours. There is a 30% chance
that MVFR CIGs will dissipate after 20Z.

KBUR...Overall, moderate confidence in 12z TAF. Timing of flight
cat changes could be off by +/- 2 hours. There is a 30% chance
that MVFR CIGs will dissipate after 20Z.

&&

.MARINE...20/243 AM.

For the Outer Waters, moderate confidence in the current
forecast. Winds and seas will remain below Small Craft Advisory
(SCA) levels through mid morning, then by mid-morning through mid
afternoon, a Small Craft Advisory will be in effect for gusty NW
winds and choppy seas through this afternoon. The southern zone
(PZZ676) will be (SCA) this afternoon through early this evening.
At that time, there is a 70% chance for Gale force winds to
develop through late tonight or pre-dawn hours Sunday. Gale
Watches were upgraded to Gale Warnings, and another Gale Warning
was added for the southern portion of the outer waters in (PZZ676)
through the same time period early Sunday morning. There is a 50%
chance for more Gale force winds for the outer waters Sunday
afternoon and evening hours.

For the Inner Waters north of Point Sal, moderate confidence in
current forecast. Winds and seas will remain below SCA levels
this morning, then a (SCA) will be in effect from noon today
through early this evening. At that time the Gale Watch that was
in effect, will be upgraded to a Gale Warning through late tonight
or pre-dawn Sunday morning. There is a good chance that a (SCA)
will be needed for Sunday afternoon into the overnight hours.

For the Inner Waters south of Point Conception, moderate
confidence in current forecast. Winds and seas are expected to
remain below SCA levels through this morning. However, a (SCA) has
been issued for the Inner Santa Barbara Channel for this afternoon
and continue into Sunday morning. The main focus for the (SCA)
will be the western portion, while the eastern portion will
encounter variable winds between 5 and 15 kt for the most part.
Otherwise, winds for the remaining inner waters, should remain
below (SCA) thresholds. There will be some local NW winds to 20 kt
around the NW portion of (PZZ655) or around Anacapa Island this
afternoon and evening hours. From Sunday afternoon through
Wednesday, winds and seas are expected to remain below SCA levels.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 2 PM this afternoon to 6 AM PDT
      Sunday for zone 59. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from noon today to 6 PM PDT
      this evening for zone 645. (See LAXMWWLOX).
     Gale Warning in effect from 6 PM this evening to 3 AM PDT
      Sunday for zones 645-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 9
      AM PDT Sunday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zones 670-673. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Sunday for zones 670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 6
      PM PDT this evening for zone 676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (MON-FRI).

No significant hazards expected.

&&

$$

PUBLIC...Rorke
AVIATION...Kaplan
MARINE...Kaplan
SYNOPSIS...30

weather.gov/losangeles

NWS LOX Office Area Forecast Discussion