Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 232357
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
457 PM PDT Mon Apr 23 2018

.SYNOPSIS...23/1159 AM.

A weak high pressure ridge, moderate onshore flow, and overnight
through morning coastal low clouds and fog are expected for the
week. As a weak low pressure system approaches the area later in
the week, temperatures will cool a few degrees through Saturday.

&&

.SHORT TERM (TDY-THU)...23/112 PM.

Quiet weather pattern next several days with a solid, though
relatively shallow marine layer and moderate onshore flow. Don`t
really see any mechanisms to alter the low cloud coverage or depth
significantly at least through mid week or so. Temps also will be
more or less the same as today with just minor day to day
fluctuations based on stratus clearing time and onshore strength.
Clouds will likely linger at some beaches through the afternoon,
much like they did today north and west of Malibu.

By Thu the upper low that will have been only slowly moving
towards the coast earlier in the week will finally start to lift
out to the northeast. As it does it will shove the weak upper
ridge currently over us to the east and result in more cyclonic
flow aloft and likely a deepening of the marine layer. So the
trends for Thu should be cooler with slower clearing and stronger
onshore flow.

.LONG TERM (FRI-MON)...23/120 PM.

There could be a little increase in northerly flow early Friday as
the first little trough passes through but overall probably little
change going into Friday with the marine layer coverage and temps.
There are differences in the handling of the upper pattern over
the weekend and into early next week but either way we should be
looking at a deeper marine layer and temps dropping below normal
as heights drop quite a bit, though very little chance of any
precip aside from possibly some morning drizzle, especially
Sunday/Monday. Both those days could have pretty slow clearing,
even inland.

&&

.AVIATION...23/2354Z.

At 23Z, the marine layer depth was near 800 feet deep at KLAX.
The top of the inversion was near 2000 feet with a temperature
around 21 degrees Celsius.

Moderate confidence in the current forecast. At coastal terminals,
conditions will deteriorate to the LIFR to IFR category through
06Z. VLIFR conditions are likely at Central Coast terminals
through 14Z or 15Z. Otherwise, conditions will gradually lift one
category between 06Z and 14Z. MVFR conditions could linger at
coastal terminals into Tuesday afternoon, especially KSBA and
KOXR.

KLAX...VFR conditions will deteriorate to LIFR between 02Z and
04Z. There is a 30 percent chance of VLIFR conditions between 03Z
and 08Z. MVFR conditions should develop between 11Z and 15Z and
there is a 30 percent chance that MVFR conditions could linger
until as late as 20Z and a 20 percent chance that MVFR conditions
could linger throughout Tuesday afternoon.

KBUR...VFR conditions are expected throughout the period, except
for a 10 percent chance of MVFR visibility between 13Z and 15Z.

&&

.MARINE...23/122 PM.

Widespread fog with visibilities of one mile or less will likely
persist through Tuesday morning, and possibly reform at night and
continue through Thursday. The afternoon and evening hours should
be slightly improved, but areas of reduced visibilities will
linger.

High confidence in winds and seas remaining below Small Craft
Advisory (SCA) strength everywhere through Wednesday. Winds will
be increasing Thursday through Saturday with widespread SCA
conditions and building short period seas likely.

&&

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

&&

.HAZARD POTENTIAL OUTLOOK (THU-MON).

No significant hazards expected.

&&

$$

PUBLIC...MW
AVIATION...Hall
MARINE...Kittell/Boldt
SYNOPSIS...B

weather.gov/losangeles



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