226
FXUS66 KLOX 181255
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
555 AM PDT Fri Oct 18 2024

.SYNOPSIS...18/333 AM.

Locally gusty northerly winds are expected to continue thru early this
morning, before shifting to a northeast Santa Ana wind event
later this morning through Saturday. Warmer temperatures and lower
humidities will impact much of the area through Saturday. Warm
and dry weather is expected next week with near to slightly above
normal temperatures common in many locations.

&&

.SHORT TERM (TDY-SUN)...18/553 AM.

Skies have cleared across the forecast area, except in southern
and eastern L.A. County, where patchy clouds persisted. Expect
these clouds to be gone by mid morning, with sunny skies across
the region today. N-S gradients remained offshore, but they have
begun to decrease in magnitude. At the same time, W-E gradients,
while still weakly onshore, have trended sharply offshore.

Winds at 850 mb have shifted to northeasterly, and are expected
to increase this morning, reaching 50 to 55 knots in the mtns of
L.A. County by mid morning. Strong subsidence associated with the
right front quadrant of a northerly jet to the east of the region
will overspread the area this morning. This will cause gusty NE
winds to become rather widespread in the valleys of L.A./VTU
Counties, the mtns of L.A. County, and the Santa Monica Range.
Gusty winds will also spread into coastal sections of VTU County
and to the Malibu Coast. For the most part, expect advisory level
winds today, though there will probably be some isolated gusts to
High Wind Warning levels, (60-65 mph) in the most wind-prone
locations. Expect winds to remain just below advisory levels in
the VTU County mtns, though advisory level winds may persist in
the northern VTU County mtns and thru the I-5 Corridor this a.m.

An upper low was located in southern Nevada early this morning.
This low will move east southeastward thru Arizona today. Heights
and thicknesses will begin to rise today, especially across SLO
and SBA Counties, farthest from the upper low and closest to the
building ridge in the eastern Pacific. Compressional warming due
to the offshore flow and sinking air will result in warming west
of the mountains, but it will be modified somewhat due to the cold
air advection pouring into the region from the north and east.
Expect some cooling in the Antelope Valley and the mountains
today, with warming west of the mtns, especially in the lower
valleys and on the coastal plain. Some of the warmest locations
could have highs near 80 degrees today.

The upper low will wobble over Arizona tonight and Sat while
weakening. Heights and thicknesses will generally rise across the
forecast area. While upper support for winds will diminish some,
it will still be fairly decent. In addition, low level gradients
will be more strongly offshore between KLAX and KDAG Sat morning.
Skies will be clear across the region. After somewhat of a lull in
the winds late this afternoon into tonight, winds are expected to
increase again late tonight, with another peak Sat morning. As a
result, the Wind Advisories remain in place thru Sat afternoon.
Once again, local High Wind Warning gusts to 60-65 mph are
possible in the most wind-prone areas Sat morning. Max temps
should be up several degrees in most areas Sat, with highs of
80 to 85 degrees widespread in the lower valleys and across the
coastal plain away from the beaches.

The upper low will very slowly pull northeastward Sat night and
Sun, only making it as far as southwestern Colorado Sun afternoon.
Offshore pressure gradients will continue Sat night/Sun morning,
but they will be weaker and there will be little upper support.
There could be some locally gusty NE winds across the mtns and
valleys of L.A./VTU Counties, but they should be below advisory
levels. Skies will remain clear. Rising heights and thicknesses
and some warming at 950 mb should lead to a bit more warming Sun,
especially in the Antelope Valley, the mtns and the interior
valleys, with less warming on the coastal plain. Max temps could
get close to 90 degrees in the warmest valley locations. There may
actually be some cooling near the beaches Sun as gradients turn
onshore in the afternoon.

.LONG TERM (MON-THU)...18/547 AM.

The ridge off the West Coast will flatten on Mon as a broad trough
moves into the eastern Pacific. Falling heights and increasing
onshore flow may bring some cooling, especially to coastal and
lower valley areas. Some night thru morning low clouds and fog may
return to coastal areas, possibly as early as Mon morning, but
more likely Mon night/early Tue.

An upper high over southern Texas and Mexico will move westward
and expand into the forecast area Tue and Wed, causing heights to
rise. In addition, there will be some offshore N-S gradients Tue,
with W-E gradients turning offshore Wed morning. Expect mostly
clear skies, except for some night/morning low clouds and fog near
the coast. There should be a few degrees of warming Tue, with max
temps again approaching 90 degrees in the warmest valley locations.
A bit more warming is possible Wed. A large broad trough will move
into the eastern Pacific by Thu. Though heights will remain quite
high, they will begin to lower some, and flow should turn onshore.
This may bring some cooling Thu, especially to coastal areas,
though temps should still be well above normal for late October.

&&

.AVIATION...18/1128Z.

Due to a data outage, current marine layer and inversion height
data is not available for KLAX.

High confidence in VFR conds for all sites. Low to moderate
confidence in timing of changes in wind speeds/direction.

Brief MVFR cigs may develop at KCMA, KOXR, KLGB, KLAX, or KSMO
thru 17Z.

KLAX...Moderate to high confidence in 12Z TAF. High confidence in
VFR conds thru the period, with the exception of a 10% chance for
very brief MVFR cigs developing at some point thru 17Z. Moderate
confidence in wind speed/directions and timing of wind changes.
There is a 40% chance for an east wind component of 6 kt 14Z-18Z.

KBUR...Moderate to high confidence in 12Z TAF. High confidence in
VFR conds thru the period. Moderate confidence in wind
speed/direction and timing of wind changes.

&&

.MARINE...18/336 AM.

For the outer waters from the Central Coast to San Nicolas
Island, Gales have subsided and SCA winds/seas are expected thru
tonight, with a lull expected in the southern zones from Pt Sal to
San Nicolas Island from late this morning thru the late
afternoon. Then, winds and seas will remain sub-advisory level
from Sat thru Tues.

For the inner waters along the central coast, Gales have subsided
and SCA winds are expected (50-60% chance) thru this morning.
There is a 20-30% chance for brief SCA winds this
afternoon/evening. Otherwise, conds are expected to remain sub-
advisory thru Tues.

For the Santa Barbara Channel, NW to NE winds are likely (50-70%
chance) from much of this afternoon thru late evening. Santa Anas
will bring NE to E gusts to the eastern portion, and NW winds will
likely impact the rest of the channel. For tomorrow afternoon thru
evening, there is a 30-50% chance for SCA winds from the NW.
Otherwise, sub-advisory conds are expected thru Tues.

For the inner waters off the LA and OC coasts, NE to NW winds are
expected (70-80% chance) much of the time thru Sat afternoon. NE
winds due to Santa Anas will impact a corridor from the Oxnard
Harbor to Santa Monica, with strongest winds downsloping thru the
canyons from Pt Mugu to Pt Dume and out to Anacapa Island south to
Santa Barbara Island this morning and tomorrow morning (30% of
local gusts to 35 kt possible). There is also a 30-50% chance of
SCA winds from the OC coast to south of Catalina Island each
morning. NW winds will impact most of the waters in the afternoon
thru evening hours today/tonight before transitioning back to NE
Sat morning. From Sun thru Tues, conds are expected to be below
SCA levels.

Seas are likely near their peak, and will rapidly drop off thru
Sat to below SCA levels.

&&

.FIRE WEATHER...18/554 AM.

Elevated to potentially critical fire weather conditions are
possible across the area through Saturday.

This morning, the winds will shift to the northeast with weak
to moderate Santa Ana winds expected through Saturday evening. As
usual, the strongest winds will occur across Ventura and Los
Angeles counties with weaker winds across San Luis Obispo and
Santa Barbara counties. As the Santa Ana winds develops, relative
humidity will drop into the teens, and even locally down into the
single digits, across the area. There is the potential for an
extended period of critical fire weather conditions across many
areas of Ventura and Los Angeles counties. Therefore, FIRE WEATHER
WATCHES are in effect from 800 AM Friday through 800 PM Saturday
for many areas of Ventura and Los Angeles counties (see LAXRFWLOX
for the details). Across San Luis Obispo and Santa Barbara
counties, elevated fire weather conditions can be expected due to
weaker northeasterly winds.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 3 PM PDT Saturday for
      zones 88-354-355-358-362-369>375-379-380. (See LAXNPWLOX).
     Beach Hazards Statement in effect until 2 PM PDT this
      afternoon for zones 340-346. (See LAXCFWLOX).
     Beach Hazards Statement in effect until noon PDT today for
      zone 354. (See LAXCFWLOX).
     Wind Advisory remains in effect until 6 AM PDT early this
      morning for zones 377-378. (See LAXNPWLOX).
     Red Flag Warning in effect from 9 AM this morning to 6 PM PDT
      Saturday for zones 288-358-369>376-378>380. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 9 AM PDT this morning
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until noon PDT Saturday for
      zone 655. (See LAXMWWLOX).
     Small Craft Advisory in effect until midnight PDT tonight for
      zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until noon PDT today for zones
      673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB
AVIATION...Lewis
MARINE...Lewis/Smith/Black
FIRE...Thompson/DB
SYNOPSIS...MW/Lewis

weather.gov/losangeles

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