295
FXUS66 KLOX 151137
AFDLOX

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

.SYNOPSIS...14/843 PM.

Strong to locally damaging north to northwest winds will affect
the interior mountains in northwest Los Angeles, northern and
central Ventura County, and southern and eastern Santa Barbara
Counties, as well as the Santa Barbara County South Coast and
Santa Ynez Range. The timing of these winds will be this evening
through the weekend. Warm to hot conditions will affect the region
with sunny skies on Saturday, and a slight cooling trend is
expected for Sunday. Dry conditions are expected through the
weekend. Low clouds will return to the coasts and coastal valleys
next week.

&&

.SHORT TERM (TDY-MON)...15/436 AM.

Skies were clear across the entire forecast area this morning,
although there were some low clouds just south of L.A. County
which may push into south coastal sections for a few hours this
morning. Any low clouds should dissipate by mid morning.
The pressure gradient between KLAX and KDAG has weakened during
the past 24 hours, but the real story is that the N-S gradients
are increasingly offshore. The gradient between KSBA and KSMX
was about 4.5 mb offshore, and onshore gradient between KLAX and
KBFL and between KSBA and KBFL have turned offshore during the
past 24 hours, both running around 2.5 mb offshore.

Gusty northwest to north winds were occurring across much of SBA
County, the mtns of Ventura County, the I-5 Corridor and the
foothills of the Antelope Valley early this morning, with wind
gusts near or above advisory levels in many of these areas.
As expected, it remained very warm in some of the foothill
locations in southern SBA County, and in L.A. County with
temps still around 80 degrees in some of these areas.

A broad upper level trough will sag southward across the forecast
area today and tonight, causing westerly flow aloft to increase.
At the same time, NW to N winds at 700 mb and 850 mb will
strengthen today. Northerly winds closer to the surface will also
increase, driven by continued sharpening N-S offshore gradients
which will peak this evening at 5.5 mb between KSBA and KSMX.
In addition to all of this, there will be increasing broad scale
subsidence across the region later today into tonight, helping to
force winds toward the surface.

Expect an increase in winds today, with High Wind Warning level
gusts to 60 to 65 mph likely across portions of southern SBA
County, in the mountains of Ventura County, through the I-5
Corridor and in the western portions of the Antelope Valley.
Advisory level winds are expected to push in the Santa Clarita
Valley as well. Have expanded Wind Advisories to include the
Central Coast from late this morning through this afternoon. Have
also included Wind Advisories for western portions of the
Antelope Valley from this afternoon through late tonight. There
is a chance that advisory level winds will affect the Santa Susana
mtns, and the northern San Fernando Valley, but for now, have
kept winds just below thresholds.

On the Central Coast, winds should peak this afternoon. In most of
the remaining windy locations, expect the winds to peak this
evening and early tonight. This particular sundowner wind event
is expected to be rather widespread across southern Santa Barbara
later today and tonight. Winds will likely impact many highly
populated areas in the city of Santa Barbara and near Montecito
and the adjacent foothills this afternoon into tonight.

Warming at 950 mb and increased northerly flow should bring
warming to most of the region today, except in the mtns, the
Antelope Valley and the interior valleys of SLO County, where
there should be slight cooling. Compressional warming of the
downslope winds will likely bring very warm to hot weather to
much of southern SBA County, including much of the city, and
possibly to near the beaches. High temperatures should rise into
the 90s to around 100 in the foothills and interior portions of
the city, and 90 degree temps may well reach some beach locations.

There will likely be a sharp temperature gradient near the coast.
Confidence in temps reaching 90 degrees at the beaches is not
especially high, since a very low inversion may prevent the winds
and heat from reaching immediate beach locations. However, this
particular pattern seems more likely than most to bring hot
weather to the immediate south coast, especially late in the day.
This will be quite a dramatic change from the very cool spring
weather that has been the norm this year.

While Sunday is not expected to be quite as hot as today will be,
gusty north winds tonight will likely keep temps in the 70s or
near 80 in the foothills all night, providing limited relief.
Therefore, a Heat Advisory is in effect through Sun evening for
the south coast of SBA County, and the Santa Ynez Range.

The combination of gusty winds, very warm to hot conditions,
and lowering humidities will bring elevated fire weather
conditions to southern Santa Barbara county and much of the
interior valleys, mountains, and Antelope Valley this weekend
(See Fire Weather Planning Forecast for more details on fire
weather concerns).

Heights will continue to lower across the region tonight and Sun
as the broad trough deepens slightly and sags southward. Expect
limited low clouds tonight/Sun morning, though clouds will likely
affect at least coastal sections of L.A. County, and possibly
southern Ventura County due to a developing eddy circulation. The
strong winds will likely dimish below warning levels by mid Sun,
but N-S gradients will remain remaining steep, so advisory level
winds may continue across southern SBA County, in the mtns of
Ventura County and through the I-5 Corridor through Sun evening.
Expect a few degrees of cooling in most areas Sun, though temps
should still be above normal for the middle of June.

An upper low will move into the Pac NW Sun night and Mon, with a
sharpening trough across CA. N-S gradients will decrease, though
they should remain steep enough for additional gusty winds late
Mon into Mon night across southern SBA County. Onshore gradients
will increase between KLAX and KDAG. Expect more widespread night
thru morning low clouds and fog Sun night/Mon. Lowering heights,
and cooling through the atmosphere should bring several degrees of
cooling to most of the region on Mon.

.LONG TERM (TUE-FRI)...14/301 PM.

For middle to latter parts of next week, broad and high-
amplitude upper troughing will persist across the western CONUS,
as a series of cyclonic perturbations advance through the flow
across the northwest states and adjacent Canada. Subsidence
upstream of the trough will favor continued surface ridging over
the east Pacific waters. This will maintain gusty northwest to
north winds in terrain-favored areas such as the I-5 corridor and
nearby VTA County Mountains and western Antelope Valley Foothills.
Present indications are that gusts should remain below Wind
Advisory thresholds starting Tuesday. However, there will be some
possibility for occasional advisory-level gusts (20% chance) if
smaller-scale enhancements to the east Pacific surface ridging
were to materialize.

The overall coast-parallel orientation of the low-level flow
across the coastal waters -- potentially favoring mesoscale eddy
development around the southern Channel Islands -- along with an
increasingly onshore surface pressure gradient across the larger-
scales, suggest that marine stratus will likely be supported
throughout middle and latter parts of next week. This would
especially be the case over a broader area of the coasts and
coastal valleys south of Point Conception. This could be
accompanied by night and morning fog and/or drizzle. Scattering
out and/or clearing of marine stratus should be less and less
from day to day as the marine layer deepens.

Meanwhile, compressional heating from downslope flow over
interior areas, beneath gradually building midlevel heights, will
support a warming trend farther inland through late week. This
will strengthen the temperature gradient across the forecast area
from day to day, with high temperatures by late next week
reaching the middle and upper 90s to around 100 degrees across the
interior valleys. High temperatures closer to the coast may not
rise above the upper 60s or lower 70s.

Otherwise, lacking midlevel moisture will prevent precipitation
development through the end of next week.

&&

.AVIATION...15/1125Z.

At 1000Z at KLAX, the marine layer was 300 ft deep. The top of
the inversion was at 2800 ft with a temperature of 28 C.

Overall, moderate to high confidence in 12Z TAF package. There is
a 40-60% chance of MVFR VSBYs 12Z-17Z for coastal sites south of
KSBA. There is a 50% chance of LIFR/VLIFR conditions at KLGB
12Z-16Z.

Gusty northerly winds will develop today and continue through the
TAF period. So, there could be some light turbulence/LLWS across
the mountains and foothills.

KLAX...Moderate to high confidence in 12Z TAF. There is a 50%
chance that MVFR VSBYs will not develop in the 12Z-17Z time frame.
There is a 10-15% chance of LIFR/VLIFR conditions 12Z-16Z. No
significant easterly wind component is expected.

KBUR...High confidence in 12Z TAF as CAVU conditions are
anticipated through the period.

&&

.MARINE...15/147 AM.

For the Outer Waters, high confidence in current forecast. Winds
have increased to Gale force levels this morning and will remain
at Gale force levels through Monday. So, GALE WARNINGS will
remain in place through Monday (with a 20% chance of Storm force
winds today and Sunday). Seas will peak in the 12 to 15 foot range
today 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 today through Sunday and a GALE WARNING remains in
effect. Seas will peak in the 10 to 13 foot range through Sunday.
For Monday through Tuesday, there is a 60-80% chance of SCA level
winds. On Wednesday, winds and seas are expected to 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 SCA level winds increasing to Gale
Force Winds today and continuing at Gale force levels through
Sunday with a GALE WARNING remaining in effect. 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 today through Sunday with high confidence in winds and seas
remaining 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 next week.

&&

.BEACHES...15/147 AM.

Short-period wind waves, due to gale force winds, will generate
significant surf conditions along the local beaches today through
Monday. High surf conditions, 4 to 8 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...14/941 PM.

Rapidly increasing northwest to north winds are expected
tonight, especially across southern Santa Barbara County, the
Ventura county mountains, and I5 corridor where gusts of 35 to 50
mph are likely with isolated gusts to 65 mph possible. Meanwhile,
the air mass will warm and dry, with widespread 8 to 15 percent
humidities in the mountains and deserts. High temperatures between
90 and 100 will be common inland of the beaches. Poor overnight
recoveries in the foothills are also expected. This warm and dry
air will descend into some coastal foothills, including southern
Santa Barbara County. As a result, there is an elevated 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. The gusty wind pattern is expected to continue into early
next week.

&&

.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).
     Wind Advisory 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 Sunday
      for zones 349-351-376>378-381. (See LAXNPWLOX).
     Heat Advisory remains in effect from 9 AM this morning to 8
      PM PDT Sunday for zones 349>352. (See LAXNPWLOX).
     Wind Advisory remains in effect until 6 PM PDT this evening
      for zones 350-352-353. (See LAXNPWLOX).
     High Wind Warning remains in effect from 6 PM this evening to
      11 AM PDT Sunday for zones 350-352-353. (See LAXNPWLOX).
     High Surf Advisory in effect until 7 PM PDT Monday for zone
      354. (See LAXCFWLOX).
     Wind Advisory in effect from 3 PM this afternoon to 3 AM PDT
      Sunday for zone 383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 11 AM PDT this morning
      for zones 645-650. (See LAXMWWLOX).
     Gale Warning in effect from 11 AM this morning to 2 AM PDT
      Monday for zones 645-650. (See LAXMWWLOX).
     Gale Warning in effect until 2 PM PDT Monday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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