341
FXUS66 KLOX 161134
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
434 AM PDT Sun Jun 16 2024

.SYNOPSIS...16/345 AM.

Warm to hot conditions are expected again today, although it will
be a bit cooler in most areas. More significant cooling is likely
Monday, then minor changes through Wednesday. Temperatures will
then trend upwards by the end of this week. Gusty north to
northwest winds will affect portions of the region, including
southern Santa Barbara County, the Interstate 5 cooridor, Antelope
Valley, and the Central Coast, through at least Monday night.

&&

.SHORT TERM (TDY-TUE)...16/434 AM.

Strong NW to N winds continued across much of southern SBA County,
the mountains from eastern SBA County thru L.A. County, through
the I-5 Corridor, in the foothills of the Antelope Valley and in
the Santa Clarita Valley. Temperatures were still in the mid 70s
to around 80 degrees in some foothill locations of SBA County and
L.A. County early this morning. An eddy circulation has developed
across the inner waters, and low clouds have pushed into southern
L.A. County. Expect low clouds to push in to most of the L.A.
County coast this morning, and possibly into the San Gabriel
Valley. N of Pt Conception, areas of low clouds have developed
across the southern portions of the Central Coast and the Santa
Ynez Valley due to upslope flow against the north slopes of the
Santa Ynez Range. Clouds should clear in most areas by mid
morning. There will probably be areas of smoke from the Post Fire
across portions of L.A. County today.

An unseasonably strong and cold upper low will move into and
across Washington state today, then into Idaho and eventually
Montana tonight and Mon. To the south of this upper low, a trough
will sharpen across CA later today and tonight, then it will move
east and flatten Mon. Strong westerly flow aloft will continue
across the region through tonight, then fast west to northwest
broadly cyclonic flow will continue through Tue. At the surface,
N-S gradients will remain strong right through early Tue.

As a result, a long duration strong northwest to north wind event
will affect many parts of Southwest California through at least
Mon night. Winds will likely be strongest this morning, and again
late this afternoon through late tonight, with gusts to 60 to 65
mph in the more favored locations. High Wind Warning level winds
may be somewhat less widespread tonight, but they will still
likely occur across southwestern SBA County, the interior mtns of
SBA County, the Ventura County mtns, through the I-5 Corridor, and
in the western foothills of the Antelope Valley. While winds
should drop below High Wind Warning levels in southeastern SBA
County this morning, winds will likely remain at advisory level at
times through late tonight, and possibly again late Mon and Mon
night.

Advisory level NW winds will likely continue in the Antelope
Valley through late tonight, and will likely redevelop this
afternoon and evening on the Central Coast. There will likely be
another round of gusty NW winds in the Santa Clarita Valley
tonight after a lull later this morning, and wind advisories may
have to be extended there through at least late tonight.

With falling heights and some cooling through the atmosphere,
max temps today should be a few degrees lower than they were on
Sat in most areas. However, they should still be somewhat above
normal. Temps will be very tricky across southern SBA County, as
warm downslope northerly winds will be battling with the cooler
marine air pushed northward by the eddy circulation in the inner
waters. It does appear that there will be significant cooling
in southeastern SBA County today, especially near the coast from
the city eastward. However, max temps may still jump again late in
the afternoon or evening, and since it remained fairly warm this
morning, the chance of heat stress may be a bit higher than the
max temps might suggest. After some consideration, have decided to
leave the Heat Advisory as is for southern SBA County especially
since it includes the foothills which will likely get very warm
again today.

Low clouds and fog will likely be a bit more widespread tonight/Mon
morning across coastal sections of L.A. County, and clouds will
likely push into the San Gabriel Valley and possibly eastern
portions of the San Fernando Valley. By late tonight, some stratus
could push into coastal sections of Ventura County. Once again,
expect some night thru morning low clouds and fog across southern
portions of the Central Coast and in the Santa Ynez Valley. Expect
skies to clear in most areas by late morning. Heights falls and
cooling at 850 mb and 950 mb should bring several degrees of
cooling to most areas on Mon.

As mentioned, there will be another spike in the NW winds late Mon
into Mon night, but expect winds to be mostly in the Wind
Advisory level range. The low level flow will try to turn more
northeasterly Tue morning, as pressure gradients between KLAX and
KDAG turn weakly offshore. This should bring an end to the gusty
NW winds in most areas by late Mon night, but some gusty NE winds
are possible in the mtns of L.A. County Tue morning. With the
increased NE low level flow shown by the latest models, there may
be somewhat of a reduction in night thru morning low clouds and
fog across L.A. County Mon night/Tue morning. Max temps may
actually rise a bit on Tue as heights rise slightly and both N-S
and W-E gradients will be offshore to start the day.

.LONG TERM (WED-SAT)...15/308 PM.

There is good agreement among the GFS and ECMWF that the trough
will persist over the region through Thursday, and that upper
level heights will trend upwards through Friday. Late Friday into
the weekend there is greater uncertainty in the upper level
pattern, with the potential for a weak ridge to begin to build.
Daytime highs are expected to slowly trend upwards Thurday through
the weekend, crossing over to above normal for much of the region
on Friday.

The north-to-south gradient is expected to weaken Wednesday and
even flip to onshore at times. Onshore flow (both from the west
and south) is generally expected to be dominant through the
period, and thus morning low clouds and fog are likely. However
with rising upper level heights, the marine layer depth, and thus
the inland extend of stratus will be limited to the coastal planes
and will at times struggle to reach the coastal valleys. Clouds
may cling to some beaches all day, especially in Los Angeles and
Ventura Counties.

Even with less dramatic pressure gradients than in the short
term, gusty northerly-to-westerly winds will continue during the
evenings for some wind- prone locations (e.g., the I-5 cooridor,
the Antelope Valley and foothills, the Santa Barbara Southwestern
coast). At this time, wind in the extended period are likely to
be much lower impact than in the short term.

&&

.AVIATION...16/1033Z.

At 1000Z at KLAX, the marine layer was 800 feet deep. The top of
the inversion was at 3400 ft with a temperature of 25 C.

Overall, moderate to high confidence in TAF package. For most
sites, CAVU conditions are anticipated through the period.
However for KLAX, KLGB, KSMO and KSMX, CIG and/or VSBY
restrictions will be possible 12Z-17Z.

Gusty north winds will continue through the period. Light
turbulence and LLWS will be likely across the mountains and
foothills.

KLAX...Moderate confidence in 12Z TAF. There is 40% chance that
IFR conditions will not develop 12Z-17Z. For tonight, moderate
confidence in return of CIG/VSBY with a window of +/- 2 hours for
timing of return. No significant easterly wind component is
expected.

KBUR...High confidence in 12Z TAF as CAVU conditions are expected
through the period. There is a 20-30% chance for smoke to produce
some MVFR VSBYs and/or BKN040-060 conditions.

&&

.MARINE...16/138 AM.

For the Outer Waters, high confidence in current forecast. Winds
are expected to remain at Gale force levels through Monday. So,
GALE WARNINGS will remain in place during this time (with a 20%
chance of Storm force winds through Sunday night). Seas will peak
in the 12 to 15 foot range through Monday. For Tuesday through
Thursday, winds will subside, but remain at Small Craft Advisory
(SCA) levels while seas drop below 10 feet.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. There is a 60-80% chance of Gale
force winds through tonight and a GALE WARNING remains in effect.
Seas will peak between 10 to 13 foot through tonight. For Monday
through Wednesday, there is a 60-80% chance of SCA level winds.
On Thursday, winds and seas should remain below SCA levels.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For the western Santa Barbara
Channel, high confidence in Gale Force Winds continuing through
tonight with a GALE WARNING remaining in effect. The winds will
be strongest from mid channel and westward. For Monday through
Thursday, there will be a 60-80% chance of SCA level winds across
the western half of the Santa Barbara Channel. Elsewhere across
the southern Inner Waters, there is a 20-30% chance of SCA level
winds today with high confidence in winds and seas below SCA
levels Monday through Thursday.

Across all of the coastal waters, steep and dangerous seas can be
expected through early this week.

&&

.BEACHES...16/139 AM.

Short-period wind waves, due to gale force winds over the nearby
coastal waters, will generate significant surf conditions along
the local beaches today through Monday. High surf, 4 to 7 feet,
will impact the beaches of Ventura county. For the beaches along
the Central Coast as well as Los Angeles county, elevated surf
conditions will continue through Monday. Along with the surf
conditions, dangerous rip currents can be expected into early this
week.

&&

.FIRE WEATHER...15/843 PM.

&&

Gusty northwest to north winds are expected to continue through
Monday, peaking in intensity tonight with a secondary peak
Sunday night into early Monday. Wind gusts of 30 to 50 mph will
be common at times through the period for the Central Coast,
mountains of Santa Barbara, Ventura and northwest Los Angeles
County as well as Antelope Valley (strongest in the mountains and
deserts). Isolated gusts to 65 mph will be likely in the
strongest periods of wind across the Santa Ynez Range and I-5
corridor. Meanwhile, a warm and dry air mass will remain in place,
with widespread 8 to 15 percent humidities across the interior
on Sunday, and 12 to 20 percent on Monday. Poor overnight
recoveries in the foothills are also expected. The warm and dry
air will continue to descend into some coastal foothills on
Sunday, including portions of southern Santa Barbara County. The
combination of gusty winds, warm temperatures, and low humidities
will continue to bring elevated to brief critical fire weather
conditions across southern Santa Barbara county through Sunday
night, and all interior areas through Monday. There is an
increased risk for fast growing grass fires over much of the
area, that could transition into wildfires where the fuel beds
are most abundant and dry.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect through Monday evening for
      zones 87-340-346-362-366. (See LAXCFWLOX).
     Wind Advisory remains in effect until 11 AM PDT this morning
      for zone 88. (See LAXNPWLOX).
     Wind Advisory remains in effect from 11 AM this morning to 8
      PM PDT this evening for zones 340-341-346-347. (See LAXNPWLOX).
     High Wind Warning remains in effect until 11 AM PDT Monday
      for zones 349-351-353-376>378-381. (See LAXNPWLOX).
     Heat Advisory remains in effect until 8 PM PDT this evening
      for zones 349>352. (See LAXNPWLOX).
     High Wind Warning remains in effect until 11 AM PDT this
      morning for zones 350-352. (See LAXNPWLOX).
     High Surf Advisory in effect until 7 PM PDT Monday for zone
      354. (See LAXCFWLOX).
     Wind Advisory remains in effect until 3 AM PDT Monday for
      zones 356-383. (See LAXNPWLOX).
PZ...Gale Warning in effect until 2 AM PDT Monday for zones
      645-650. (See LAXMWWLOX).
     Gale Warning in effect until 7 PM PDT Monday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB/Schoenfeld
AVIATION...RAT
MARINE...RAT
BEACHES...RAT/Cohen
FIRE...Gomberg/Munroe
SYNOPSIS...DB

weather.gov/losangeles

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