687
FXUS66 KLOX 160344
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
844 PM PDT Sat Jun 15 2024

.SYNOPSIS...15/839 PM.

Warm to hot conditions are expected again Sunday, although with
slightly cooler highs, and continued gradual cooling each day
through Monday or Tuesday. Temperatures will then trend upwards by
the end of the upcoming 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 Monday morning.

&&

.SHORT TERM (SAT-TUE)...15/836 PM.

Long duration strong northwest to north wind event impacting many
parts of Southwest California through Monday. Areas experiencing
these winds will continue to see elevated to brief critical fire
weather conditions (please see fire discussion for more details).
The strongest winds tonight are focused across southern Santa
Barbara county, the Interstate 5 corridor, Ventura County
mountains, and western Antelope Valley foothills. These areas are
under a High Wind Warning where damaging wind gusts of 55 to 65
mph will be likely. Potential impacts include downed
trees/powerlines as well as power outages. Areas under a wind
advisory tonight include the Antelope Valley, Lake Casitas, and
Santa Clarita Valley where gusts of 35 to 50 mph will be common.

The Post Fire which originated near Gorman this afternoon has
grown quickly to around 3600 acres as of 8 pm due to the strong
northwest winds and low humidities. The Post Fire will continue
to be under the influence of strong northwest to north winds
through Monday morning, with the strongest winds expected
tonight (after 10 pm) and again Sunday night. During these times,
wind gusts of 50 to 65 mph can be expected (strongest across
mountain ridgetops).

As far as the sundowner wind event occurring this evening, we
are seeing a very strong northwest pressure gradient between
Santa Maria and Santa Barbara peaking at -6 mb as of 8 pm. This
in combination with some upper level wind support and thermal
advection is generating a strong and widespread sundowner wind
event tonight. So far, the strongest winds have been focused
between Gaviota and San Marcos Pass as well as the hills above
Montecito where wind gusts of 40-58 mph have been observed. In
addition, we saw a late afternoon temperature spike in areas that
saw the downslope winds, with Santa Barbara Airport observing an
impressive high temperature of 93 degrees. The sundowner winds
have already impacted the Goleta area and adjacent foothills, with
high resolution WRF model data showing the likelihood of the
sundowner winds surfacing across other populated areas near Santa
Barbara, Montecito, and Carpinteria (especially in the hills)
within the next few hours. While the sundowner event looks to be
fairly strong once again across western areas on Sunday
afternoon/night, there does appear to be an eddy marine influence
that will likely prevent the winds from surfacing across the lower
elevations from Goleta to Montecito during Sunday`s event. The
widespread and long duration of the Sundowner winds in southern
Santa Barbara county will make this a rather rare event for this
time of year.

Current satellite imagery showing clear skies with the exception
of the smoke from the Post Fire impacting the Antelope Valley
and portions of the LA/Ventura county mountains. Not much in the
way of marine layer clouds expected tonight, with the exception
of the LA county coast which could see some low clouds later
tonight into Sunday morning. With heights lowering across the
region on Sunday, looking for most areas to see at least a few
degrees of cooling. However, interior areas and areas that
continue to see downslope winds will likely experience
temperatures above 90 degrees. Additional cooling is then expected
on Monday.

*** From previous discussion ***

This pattern of winds, including warning level gusts, is expected
to continue through Monday mornings. In fact, latest model runs
show an upward trend in wind speeds for Sunday night through
Monday morning, and this period may see the strongest wind of the
event. This is due to the dropping of the upper level trough over
the region, which allows for better upper level support as
pressure contours become more alighted through the atmosphere.

.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...15/2332Z.

At 2000Z at KLAX, the marine layer was 1000 ft deep. The top of
the inversion was at 3200 ft with a temperature of 28 C.

Overall, moderate to high confidence in TAF package.

CAVU conditions are anticipated at most locations through the
period. However, CIG/VSBY restrictions in a returning marine
layer will likely affect coastal LA County late tonight and Sun
morning (60-80% chance), including KLAX, KLGB, and KSMO. Onset
timing of CIG/VSBY restrictions may vary by +/- 2 hours from
current forecasts. Gusty northerly winds will continue through the
TAF period, and there could be some light turbulence/LLWS across
the mountains and foothills.

KLAX...Moderate to high confidence in TAF. There is a 40% chance
that CIG/VSBY restrictions do not develop. No significant
easterly wind component is expected.

KBUR...High confidence in TAF as CAVU conditions are anticipated
through the period.

&&

.MARINE...15/843 PM.

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
Wednesday, 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 Sunday and a GALE WARNING remains in effect.
Seas will peak between 10 to 13 foot through Sunday. For Monday
through Tuesday, there is a 60-80% chance of SCA level winds. On
Wednesday, 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
Sunday with a GALE WARNING remaining in effect. The winds will be
strongest from mid channel and westward. For Monday through
Wednesday, 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 through Sunday with high confidence in winds and seas
below SCA levels Monday through Wednesday.

Across all of the coastal waters, steep and dangerous seas can be
expected this weekend into at least early this coming week.

&&

.BEACHES...15/210 PM.

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 through the
weekend.

&&

.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 Sunday for
      zone 88. (See LAXNPWLOX).
     High Wind Warning now 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 Sunday for
      zones 349>352. (See LAXNPWLOX).
     High Wind Warning remains in effect until 11 AM PDT Sunday
      for zones 350-352. (See LAXNPWLOX).
     High Surf Advisory in effect until 7 PM PDT Monday for zone
      354. (See LAXCFWLOX).
     Wind Advisory in effect until 3 AM PDT Sunday 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...Gomberg/Schoenfeld
AVIATION...Gomberg/Cohen
MARINE...Smith
BEACHES...RAT/Cohen
FIRE...Gomberg/Munroe
SYNOPSIS...DB/RS/CS

weather.gov/losangeles

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