Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/14/20

Area Forecast Discussion

National Weather Service Los Angeles/Oxnard CA

 804 PM PST Thu Feb 13 2020

.SYNOPSIS...13/749 PM.

Temperatures for Friday and this weekend will be near to slightly
above normal as high pressure remains over the region. Areas of
coastal night to morning clouds are expected through Saturday,
and some breezy conditions will develop over southern areas on
Sunday.

&&

.SHORT TERM (THU-SUN)...13/804 PM.

Current satellite imagery showing marine layer clouds redeveloping
this evening across portions of the Central Coast. 00Z Vandenberg
sounding showing the marine layer depth around 1500 feet with a
fairly well established marine inversion. Some patchy dense fog is
also possible overnight into early Friday morning across the
Salinas Valley. For areas south of Point Conception, the marine
layer depth is shallower with a weaker inversion, as evident by
the ACARS data showing a depth around 800 feet across the LA
basin. As a result, expecting low clouds and fog to mainly be
confined to the coastal areas for LA/Ventura counties. Little
change in temperatures expected on Friday, with pressure
gradients near neutral in the early morning, becoming weakly
onshore once again in the afternoon hours.

*** From previous discussion ***

A weak and short-lived ridge nudges in from the west on Saturday.
With weak offshore trends expected, there may be a limit as to
the formation of marine layer stratus. Again the most likely
locations will be the Central Coast and southern LA County coast.
Otherwise another sunny day and temperatures will warm a few
degrees, with low 70s expected in the valleys.

On Sunday the ridge gets squashed by an inside slider moving into
the Pacific Northwest. It won`t really affect our weather much
other than increase onshore flow and lead to slight cooling along
the coast.

.LONG TERM (MON-THU)...13/222 PM.

The inside slider then digs southward into Nevada on Monday.
However, it does not dig as sharply as was previous forecasted.
Northerly pressure gradients will increase, but not quite as
drastically as previous model runs indicated. There will also be
less cold air advection associated with it than previously thought.
However, advisory level northerly winds are still possible for at
least the LA mountains. Otherwise there will be some high clouds
and temperatures over the mountains and interior valleys will cool
by several degrees.

By Tuesday through late week, the models diverge quite a bit. The
ECMWF indicates the trough pushing to the south while a ridge
noses in for Wednesday and Thursday keeping things dry. However,
the GFS indicates that the trough lingering Tuesday and cuts off
into a closed low just along the coast of Point Conception on
Wednesday. Ensembles don`t really support any precipitation with
this solution, so have kept the forecast dry with partly cloudy
skies. Winds transition from the north to northeast during this
period. Gradients continue to look decent, so there will be the
potential for advisory level winds over Santa Ana prone areas.

&&

.AVIATION...13/2355Z.

At 2355Z, the marine inversion at KLAX was based at 700 feet. The
top of the inversion was 1700 feet with a temperature of 13
degrees Celsius.

North of Point Conception, moderate to high confidence in 00Z
TAFs. For tonight, high confidence in return of IFR/LIFR
conditions, but low to moderate confidence in timing.

South of Point Conception, moderate confidence in coastal TAFs and
high confidence in valley/desert TAFs. CAVU conditions for all
sites through this evening. For later tonight into early Friday
morning, high confidence in return of IFR conditions to
KLAX/KSMO/KLGB, but low confidence in timing. For KCMA/KOXR, there
is a 30% chance that CIG/VSBY restrictions will not develop. For
KSBA, there is a 30% chance of IFR conditions 09Z-17Z.

KLAX...Overall, moderate confidence in 00Z TAF. High confidence
in CAVU conditions through this evening. For tonight, high
confidence in return of IFR conditions, but only moderate
confidence in timing (could be +/- 2 hours of current 10Z
forecast). No significant easterly wind component expected.

KBUR...High confidence in 00Z TAF as CAVU conditions are
anticipated through TAF period.

&&

.MARINE...13/735 PM.

For the Outer Waters, high confidence in current forecast. Through
Saturday, winds and seas will remain below Small Craft Advisory
(SCA) levels. On Sunday, there is a 60% chance of SCA level
northwesterly winds. On Monday and Tuesday, there is an 80%
chance of SCA level northwesterly winds and seas.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Through Saturday, high confidence
in winds and seas remaining below SCA levels. On Sunday and
Monday, there is a 60-70% chance for SCA level northwesterly
winds with conditions expected to drop below SCA levels on
Tuesday.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. Generally high confidence in winds
and seas remaining below SCA levels through Tuesday. The only
exception will be the western half of the Santa Barbara Channel
where there is a 50% chance of SCA level northwest winds on Sunday
and Monday.

&&

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

&&

.HAZARD POTENTIAL OUTLOOK (SUN-THU).

Gusty northerly winds are likely Sunday night into Monday, then
transitions to a Santa Ana wind event Tuesday and Wednesday.

&&

$$

PUBLIC...Gomberg/Stewart
AVIATION...Gomberg
MARINE...RAT/Gomberg
SYNOPSIS...Phillips

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