Acton Weather

000
FXUS66 KLOX 032157
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
157 PM PST Thu Dec 3 2020

.SYNOPSIS...03/154 PM.

Gusty northeast winds are expected through Saturday and again
early next week. Critical fire weather conditions are expected
for Los Angeles and Ventura Counties through Friday and possibly
again next week. It will remain dry across the region with
temperatures above normal but with chilly nights in wind protected
locations. High surf is expected along the Central Coast through
Saturday morning and again next Tuesday.

&&

.SHORT TERM (TDY-SUN)...03/131 PM.

Winds coming down now to mostly advisory levels as expected,
though some very isolated gusts to around 60 mph still occurring
in the Santa Susanna Mountains in Ventura County (Wiley Ridge
area). Even most of the higher mountain sites are down below 40
mph. Though in general the trends and gradients are down, there
will likely be another little push overnight into Friday and
there`s enough support for some low end wind advisories in the
valleys and mountains through the morning hours so those have all
been extended to noon Friday.

A cold night tonight in wind protected locations and a hard freeze
warning is in effect for the Antelope Valley as temps there drop
into the teens. Likely one additional night of this Friday night
but still chilly through the weekend. Same with other interior
valleys and even some coastal valleys where some 30s are likely
where winds are lighter.

Daytime highs were cooler across the board as this system did end
up having decent cold air support behind it. In general highs were
down 5-10 degrees and as much as 10-15 in the mountains. Likely
some warm up Friday inland with less cold air advection, but also
less downslope warming effects as winds will be lighter.

For the weekend generally quiet weather but lingering offshore
flow and locally breezy winds during the night and morning hours,
mostly below advisory levels, especially by Sunday when offshore
gradients are very weak. A few high clouds at times otherwise
mostly clear skies. Daytime highs mostly near to slightly above
normal.

.LONG TERM (MON-THU)...03/145 PM.

Huge timing differences between the deterministic GFS and ECMWF
models regarding the back door upper low for early next week. The
ECMWF remains much faster with the movement than the GFS and
certainly favors Monday for the peak period of Santa Ana winds
while the GFS would be more towards Monday night into Tuesday. So
still pretty low confidence in the timing but decent confidence
that we`ll be in for another round of at least advisory level
Santa Ana winds early next week and very low humidities. Low
confidence as well in the temperature trends as they will largely
depend on how fast the low moves but for now some warming Tue/Wed
then cooling later the week with another trough approaching. Rain
chances still look very low through the middle of the month at
least.

&&

.AVIATION...03/1726Z.

At 1704Z at KLAX, there was no marine layer.

High confidence in CAVU TAFs (except for KSMX and KSBP) with
moderate confidence in wind speeds and timing for NE winds across
LA and Ventura Counties. Moderate turbulence is possible over and
near higher terrain. LLWS up to 20 kt is also possible.

Moderate confidence that KSMX and KSBP TAFs will remain VFR
through Fri morning.

KLAX...High confidence in CAVU TAF. There is a 40% chance of a 6
to 8 kt east wind component thru 19Z. LLWS possible through 22Z.

KBUR...High confidence in CAVU TAF. Possible Moderate turbulence
or LLWS at times.

&&

.MARINE...03/921 AM.

Outer Waters... Good confidence that Small Craft Advisory (SCA)
level hazardous seas of 10 feet will continue north of San
Nicolas Island through Friday afternoon. Afterward, seas should
lower to below SCA thresholds through early next week.

Inner Waters north of Point Sal...SCA level hazardous seas are
likely to continue through Friday afternoon. Winds are not
expected to reach SCA thresholds. Peak seas will likely reach 10
feet. The combination of a long periods swell, could cause some
higher steep waves near shore.

Inner Waters S of Point Conception...For the waters near shore
from Ventura to Santa Monica to the Channel Islands as well as
the San Pedro Channel to Catalina, expect very gusty NE-E winds
through this evening and will likely reach as far offshore as the
Channel Islands. Winds will likely impact east- facing harbors
such as Avalon Harbor and Two Harbors on Catalina Island today.

&&

.BEACHES...03/1224 PM.

The combination of a Northwest to west 8 to 10 foot swell with a
long period of 17-22 second period will cause high surf between 10
and 14 feet across the Central Coast through Friday evening.
Local sets to 17 feet can be expected at times.

As the swell progresses southward, some swell energy will filter
into the Santa Barbara Channel as well as the adjacent coastal
waters of L.A. County brining surf of 4 to 7 feet across exposed
west facing beaches starting later this afternoon. A few local
sets to 8 feet may be possible near the Ventura Harbor. A High
Surf Advisory remains in effect this afternoon for the Los Angeles
and Ventura County Coastal areas including the north and western
coast of Catalina Island and continue through very early Saturday
morning.

There is an increased risk for ocean drowning. Rip currents can
pull swimmers and surfers out to sea. Large breaking waves can
cause injury, wash people off beaches and rocks, and capsize small
boats near shore.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 10 PM PST Friday for zones
      34-35. (See LAXCFWLOX).
     Wind Advisory in effect until 3 PM PST this afternoon for
      zones 40-41. (See LAXNPWLOX).
     High Surf Advisory in effect until 2 AM PST Saturday for
      zones 40-41-87. (See LAXCFWLOX).
     Wind Advisory in effect until noon PST Friday for zones
      44>46-53-54-88-547. (See LAXNPWLOX).
     High Wind Warning in effect until 3 PM PST this afternoon for
      zones 46-53-54-88. (See LAXNPWLOX).
     Hard Freeze Warning in effect from 10 PM this evening to 9 AM
      PST Friday for zone 59. (See LAXNPWLOX).
     Hard Freeze Watch in effect from Friday evening through
      Saturday morning for zone 59. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PST Friday for zones
      240-241-244-245-547-548. (See LAXRFWLOX).
     Red Flag Warning in effect until 10 PM PST Saturday for zones
      246-253-254-288. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 6 PM PST Friday for
      zones 645-670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 8 PM PST this evening
      for zones 650-655. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (SUN-THU).

Periods of offshore winds and dry conditions could lead to
critical fire weather conditions again early next week. High surf
or strong rip currents may create hazardous ocean conditions
early next week.

&&

$$

PUBLIC...MW
AVIATION...Sweet/Kaplan
MARINE...Sweet/Kaplan
BEACHES...Sweet
SYNOPSIS...MW

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