Area Forecast Discussion
Issued by NWS Los Angeles, CA

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525
FXUS66 KLOX 232350 AAA
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
350 PM PST Tue Jan 23 2018

.SYNOPSIS...
Offshore flow and a building upper level ridge will bring a few
days of substantial warming to the region. An upper level trough
will swing a weak front into the area Wednesday night into
Thursday bringing light showers across the northern portion of
the forecast area. Strong ridge of high pressure will build in
this weekend bringing very warm and dry conditions.

&&

.SHORT TERM...(TDY-FRI)

A low pressure system about 850 miles northwest of Seattle will
drop in to our area starting late Wednesday and bringing showers
to San Luis Obispo County and a slight chance into Santa Barbara
and Ventura Counties. Clouds associated with this system are
advancing into Washington and northern Oregon.

Clear skies and ridging aloft (H5 peaking at 574 dm today) brought
5 to 10 degrees of warming to many areas today. Paso Robles has
some overnight and morning fog and stratus and this is expected to
return tomorrow.

Wednesday will be a transition day with offshore flow
switching onshore (especially up north) as the day progresses.
This will bring some cooling to coastal areas and some warming
inland. It will also likely lead to the possibility of low clouds
and fog to portions of the Central Coast by late Wednesday.

Light showers are expected along and just ahead of a weakening
cold front expected to push through the Central Coast Wednesday
night into Thursday morning. The front will likely dissipate near
Point Conception. An increase in clouds (including low clouds
near the coast) and cooling will be the main the main weather
change for areas south of Point Conception.

Gusty northwest to north winds will likely develop later Thursday
across wind prone areas. Lingering clouds and some showers are
possible across the north slopes, especially in Ventura County.

Gusty northerly winds are expected on Friday and there will be a
building ridge of high pressure.

.LONG TERM...(SAT-TUE)

Offshore winds are likely to weaken for the weekend with just a
chance of reaching advisory levels. The offshore flow combined
with a strong ridge of high pressure for this time of year (H5
near 582 dm) will bring another round of warming, with
temperatures likely reaching the low 80s for the warmer coastal
valleys this weekend.

For early next week, model guidance continues to differ on how
quickly the ridge of high pressure over the region is replaced by
a deepening trough over the Great Basin. Current forecast splits
the difference, but if current trends continue early next week may
become at least somewhat cooler and much windier than the current
forecast package suggests.

&&

.AVIATION...23/2350Z...

At 2317Z, the inversion at KLAX was around 200 ft deep. The top
of the inversion was at 1000 feet with a temperature of 19 deg C.

Overall, high confidence in 00Z TAF package. Weak offshore flow
is expected to keep most sites VFR through the period. The only
exception will be KPRB where VLIFR conditions are expected 12Z-
18Z Wed.

KLAX...High confidence in 00Z TAF with VFR conditions through Wed
evening.

KBUR...High confidence in 00Z TAF with VFR conditions through Wed
afternoon.

&&

.MARINE...23/100 PM...

For the Outer Waters, good confidence in current forecast. Winds
and seas will remain below Small Craft Advisory (SCA) levels
through Wednesday night. From Thursday through Sunday, high
confidence in both winds and seas increasing to SCA levels.

For the Inner Waters, good confidence in current forecast. For the
waters north of Point Sal, winds and seas are expected to remain
below SCA levels through Thursday. On Friday and Friday night,
seas are expected to increase to SCA levels. For the waters south
of Point Conception, winds and seas are expected to remain below
SCA levels. However, there is a 30% chance of SCA level winds
Thursday afternoon/evening across western sections.

&&

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

&&

.HAZARD POTENTIAL OUTLOOK...(FRI-TUE)
Gusty advisory-strength winds are possible Thursday and Friday
over the mountains and southern Santa Barbara County, possibly
impacting travel. Gusty Santa Ana winds could develop over next
weekend increasing the risk of fire.

&&

$$

PUBLIC...jld
AVIATION...Sirard
MARINE...RAT
SYNOPSIS...Sweet

weather.gov/losangeles



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