Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 250409
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
909 PM PDT TUE MAY 24 2016

.SYNOPSIS...

Low pressure will move across the area tonight and tomorrow,
resulting in cool weather and a slight chance of showers and
thunderstorms, mainly for the mountains and some interior areas.
Warming is expected late this week as the main upper low moves
east, but temperatures will remain near or slightly below normal
through early next week as a weak trough lingers over the area.

&&

.SHORT TERM...(TONIGHT-FRI)

An upper low spinning a few hundred miles off the Central Coast this
evening was helping to bring varying amounts of mainly stratocu to
the mtns and some cst and vly areas. There were a few light showers
in the VTU County mtns late this afternoon, otherwise dry conditions
prevailed across the region into the evening hours. However, with the
upper low forecast to move close to the s SBA County coast late
tonight, and a cyclonic flow aloft combined with a persistent lower
level moist layer, there will be the possibility of a few showers
developing over interior areas of SLO/SBA Counties and mainly over
the nrn mtns of VTU/L.A. Counties overnight. Even isolated drizzle
cannot be ruled out for coastal and vly areas s of Pt Conception.
Otherwise, partly to mostly cloudy skies will prevail for much of
the region thru the night. Areas of gusty s to w winds in the mtns
and deserts this evening will diminish some overnight.

The upper level low is forecast to slide e across VTU and L.A.
Counties thru the day on Wed, then track further e into AZ for Wed
night. A broad mainly nw flow aloft will prevail over swrn CA Thu
thru Fri with slowly rising 500 mb heights.

A slight chance to chance of showers can be expected over much of
the forecast area Wed morning due to the influence of the upper low
on the deep moist layer. A slight chance of showers and
thunderstorms will affect interior portions of SLO/SBA/VTU/L.A.
Counties for Wed afternoon, including the mtns and deserts, thanks
to some lingering instability and a piece of energy sliding down the
back side of the upper low. Overall, though, it looks like partly to
mostly cloudy skies and cool conditions can be expected across the
region. increasing onshore gradients will help to bring even
stronger winds to the Antelope Vly Wed afternoon and evening,
possibly reaching advisory levels. Gusty sw to nw winds will also
affect the Central Coast, foothills and mtns Wed afternoon and early
evening.

More extensive night and morning low clouds and fog are forecast for
the Central Coast and Santa Ynez Vly with varying amounts of clouds
over the coast and vlys of VTU/L.A. Counties. The marine layer
pattern should affect all the coast and adjacent vlys Thu night into
Fri morning, with an eddy helping to enhance the marine layer clouds
s of Pt Conception. Otherwise, partly cloudy skies can be expected
Thu night, with mostly sunny skies developing in all areas by early
Fri afternoon. Good onshore flow will prevail each day, with gusty
sw to nw winds from the Central Coast to the foothills, mtns and
deserts from the afternoon to evening hours. Gusty nw to n canyon
winds are also expected along the SBA s coast and mtns each evening.
However, it looks like winds should be mostly sub-advisory for Thu
and Fri.

Temps across the region will be 5 to 15 deg below normal on Wed,
then warm to near normal to slightly below normal for most areas by
Fri.

***FROM PREVIOUS DISCUSSION***

.LONG TERM...(SAT-TUE)

Extended models showing weak upper level trough across California
over the weekend, with continued strong onshore flow near the
surface. This will maintain mild temperatures, along with night
and morning marine layer clouds, and gusty onshore winds in the
mountains and deserts. Some weak upper level ridging expected to
follow Monday into Tuesday, leading to a few degrees of warming
across interior areas.

&&

.AVIATION...

25/0010Z...

At 2329Z...a weak marine inversion was present at KLAX at around
1700 ft deep. The top of the inversion was around 2400 ft with a
temperature of 13 deg C.

Moderate confidence overall in the 00z TAFs. Periods of low clouds
with MVFR cigs are expected at the coastal and vly airfields tonight
and Wed morning, but the timing of the clouds could be off +/- an
hour or two, be intermittent at times, and may not fall to MVFR
flight cats at some of the airfields. Otherwise, VFR conditions will
prevail thru Wed. For KWJF and KPMD, VFR conditions will continue
thru Wed along with gusty afternoon and evening winds, altho the
winds should be a bit stronger on Wed.

KLAX...Moderate confidence overall in the 00z TAF. Low clouds with
MVFR cigs are expected from about 03z to 20z. However, the timing of
the clouds could be off +/- an hour or two, be intermittent at
times, and may not even fall to MVFR at times. Otherwise, VFR
conditions will prevail at the airfield thru Wed evening.

KBUR...Moderate confidence overall in the 00z TAF. Low clouds with
MVFR cigs are expected from about 08z to 18z. However, the timing of
the clouds could be off +/- an hour or two, be intermittent at
times, and may not even fall to MVFR at times. Otherwise, VFR
conditions will prevail at the airfield thru Wed afternoon.

&&

.MARINE...24/800 PM.

Mainly light winds and small seas are expected through Wednesday
morning, with no SCA concerns. There is a high probability that
Small Craft winds will develop across the outer waters Wednesday
afternoon through at least Friday morning, and possibly through
the weekend. Models indicate a chance of gale force gusts over the
outer waters Saturday and Sunday. There is also a good chance
that SCA level wind gusts will affect the western portion of the
Santa Barbara Channel Wednesday afternoon through Wednesday night,
and again Thursday afternoon and evening. 40 percent chance that
the NW portion of PZZ655 near Anacapa Island will meet SCA
criteria as well Wednesday evening into early Thursday morning.

A Catalina Eddy will likely spin up during morning hours
Thursday through Sunday across the inner waters within the SoCal
Bight.

&&

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

&&

$$

PUBLIC...Sirard/Gomberg
AVIATION...Sirard
MARINE...Smith
SYNOPSIS...Sukup

weather.gov/losangeles



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