Area Forecast Discussion
Issued by NWS Los Angeles, CA

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487
FXUS66 KLOX 042105
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
205 PM PDT WED MAY 4 2016

.SYNOPSIS...

The onshore flow will bring overnight clouds...fog and drizzle
into early Thursday. Then a low will arrive on Thursday with
a chance of showers and thuderstorms into Saturday night...
with showers to linger in the mountains on Sunday. The
temperatures will remain below normal into early next week...then
a warming trend into midweek as a high builds in.

&&

.SHORT TERM...(TDY-SAT)

Cloudy skies and a lingering marine incursion have helped to keep
temperatures cool today across the region. Winds have increased as
well ahead of the incoming low pressure system... especially
across Ventura and Los Angeles Counties... but will remain below
advisory criteria for now.

The low center is currently off the Central Coast and will begin
to move more easterly in the next few hours. This will increase
the cloud cover and winds... result in further cooling... and
bring a chance of showers to the entire region beginning on
Thursday. Some light drizzle may come to coastal areas late
tonight.

The low center is projected to move onshore late Thursday across
southeastern California and with it will come a slight chance of
thunderstorms as well. The thunderstorm forecast is a bit tricky
as there looks to be decent instability and more buoyant energy
than usual for the region but moisture is limited in the primary
lift zones and this is projected to be an issue throughout the
event. Higher PWs will be to the south and west of the best
instability and lift and as the low center moves through it is
possible that enough is pulled in where needed for good convective
development. If so then any thunderstorms that move beyond initial
development could strengthen rapidly. If not then a ridgeline
of weak Cb clouds may be the best that can be done. So the chance
is slight... but the potential is strong.

Northern Ventura County has been the focus during the past couple
of days for the best projected instability and CAPE. Thursday and
Friday both look to have good potential and on Friday this
potential expands westward to include much of eastern Santa
Barbara County. The is a slight chance for some development in the
mountains of Los Angeles County on Thursday but the better chance
will come on Friday and Saturday. With the better moisture
availability to the south during that period it may be that the
most activity will be over the marine zones.

.LONG TERM...(SUN-TUE)

There is a chance for lingering showers on Sunday... primarily
over the mountains and especially over the Los Angeles County
mountains. The chance for thunderstorms is very low but not zero
and as the low center shifts with time there may be a last shot on
Sunday.

By Monday the low will be moving eastward... the skies clearing...
and temperatures will be warmer. A solid ridge of high pressure
will build off the coast and conditions should be dry and warming
into the next work week. Some overnight low clouds and fog may
return to the coastal areas.

&&

.AVIATION...04/1800z.

At 1610Z at KLAX the marine layer was 2800 feet deep. The top of
the inversion was 4300 feet with a temperature of 14 degrees
Celsius.

Low to moderate confidence in the 18z tafs. Marine clouds are
completely dominant in the coastal and valley sections. The deep
marine layer will deepen further as a trough approaches today with
only partial afternoon clearing expected in a few places near the
coast late this afternoon. Skies are expected to remain cloudy
through thursday morning with mostly MVFR to VFR ceilings. By
thursday morning there will also be a possibility of drizzle or
light showers in some locations.

KLAX...Low to moderate confidence in the 18z TAF. There is a 30
percent chc that MVFR cigs will scour out after 23z.

BUR...Low to moderate confidence in the 18z TAF. There is a 10
percent chc that MVFR cigs will scour out after 23z.

&&

.MARINE...04/200 PM...

For the Outer Waters, good confidence in current forecast. Winds
and seas are expected to remain below SCA levels through the
weekend. However there is a 30% chance that some SCA level gusts
could develop Friday afternoon/evening across western sections of
the Outer Waters.

For the Inner Waters, good confidence in current forecast. Winds
and seas are expected to remain below SCA levels through the
weekend.

&&

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

&&
$$

PUBLIC...KJ
AVIATION...Sweet
MARINE...Sweet
SYNOPSIS...Seto

weather.gov/losangeles



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