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000
FXUS66 KLOX 172107
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
207 PM PDT Wed Apr 17 2024

.SYNOPSIS...17/117 PM.

Dry but cooler weather with increasing low clouds and fog during
the nights and morning is expected through Friday as a weak low
pressure system moves into the area. A warming trend is expected
for the weekend before cooler temperatures return next week.

&&

.SHORT TERM (TDY-SAT)...17/144 PM.

A relatively quiet period of weather coming up over the next
several days. A weak trough is approaching the West Coast with a
ton of high clouds. Otherwise the main impact will be increasing
onshore flow and marine layer stratus (as those near the coast
south of Pt Conception today can attest to) and cooler
temperatures through Friday. Forecast soundings only indicate
minor deepening of the marine inversion tonight so there will
still be areas of dense fog near the coast and just very little if
any valley fog intrusion expected. The cooler onshore flow mainly
just reached the coastal areas but by tomorrow and Friday cooling
will reach all the way into the interior with highs topping out
in the mid to upper 70s versus the 80s today.

The cooling trend will reverse over the weekend with a brief but
effective ridge over California this weekend. Temperatures should
bounce back to the 80s inland with a 10-20% chance of an isolated
90 or two in the warmest valleys Sunday.

.LONG TERM (SUN-WED)...17/207 PM.

The weekend ridge will be short lived as the next weak trough is
expected to hit the West Coast late Monday and likely remain in
place through the week. This will generate significant cooling
across the area with a likely return of a deep marine layer by mid
to late week. Ensembles have been hinting at some precipitation
chances as well, though those were likely associated with a small
percentage of solutions that showed the upper low cutting off and
dropping much farther south along the coast. A majority favor an
open wave solution with the upper low over Oregon and extreme
northern California. There are some deeper trough solutions later
in the week and into next weekend that could squeeze out some
light precip by next weekend, probably more in the form of deep
marine layer drizzle. In any case, it looks like a long duration
of well below normal temperatures across the area starting next
week.

&&

.AVIATION...17/1751Z.

At 18Z, the marine layer at KLAX was about 500 ft deep. The top
of the inversion was at 1800 ft with a temp of 20 deg C.

VFR conds are expected in all areas thru this evening, with just
some high clouds. Widespread low clouds are expected in all
coastal areas tonight, with IFR to LIFR conds, and local VLIFR
conds on the Central Coast. There is a 20% chance that LIFR conds
will spread into the valleys late tonight.

KLAX...Moderate confidence in the 18Z TAF. There is a 20% chance
that cigs tonight will be in the MVFR category and a 20% chance
that cigs will not arrive until as late as 12Z. Any east wind
component should remain less than 6 knots.

KBUR...High confidence in the 12Z TAF with VFR conds thru the pd.
There is a 20% chance of LIFR cigs after 11Z Thu.

&&

.MARINE...17/900 AM.

A very shallow marine layer will continue to bring dense fog to
most waters south of Point Conception this morning, and could
linger through the afternoon or evening. Improved but still
reduced visibility is expected by Thursday.

There is a 60 percent chance of Small Craft Advisory conditions
for the offshore waters off the Central Coast this afternoon and
evening. Otherwise, high confidence in generally light winds
through Friday. Southeast winds around 10 knots are expected each
morning from the Santa Barbara Channel to Orange County, with some
local enhancements through the Anacapa Passage and San Pedro
Channel.

Northwest winds will be increasing over the weekend.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Thursday for
      zone 670. (See LAXMWWLOX).

&&

$$

PUBLIC...MW
AVIATION...MW
MARINE...Kittell
SYNOPSIS...MW

weather.gov/losangeles

Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox