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169
FXUS66 KLOX 130307
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
807 PM PDT Wed Jun 12 2024

.SYNOPSIS...
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12/725 PM.

Low clouds and fog are expected through at least Friday morning
across the coast and coastal valleys, with temperatures 3-6
degrees below normal. Gusty north winds are expected Friday into
the weekend, mainly in the mountains and southern Santa Barbara
County and adjacent coastal waters. Warming temperatures are
expected Friday through weekend, with faster clearing of low
clouds.
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&&

.SHORT TERM (WED-SAT)...
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12/749 PM.

***UPDATE***

The main forecast concern for this evening into Thursday involves
a significant deepening of the marine layer and a push of low
clouds well inland over all of the valleys to the interior
mountain slopes. This transition to a more extensive marine layer
clouds is caused by the approach of an upper low center that has
been southwest of the area. While the low center will still be 200
miles SW of Los Angeles at 0500 Thursday, there should be enough
lift in place to help deepen the marine layer. In addition, fairly
strong onshore gradients are in place, with the LAX to Daggett at
9.7 MB at 5 PM. With the combination of lift and the onshore push,
there will likely be patchy drizzle across the area again during
the late night to morning hours. And daytime highs will likely
drop a few degrees compared to today`s highs, due to the more
extensive low cloud coverage and slower afternoon clearing.

***From Previous Discussion***

Changes start happening rapidly Friday after the low zips off into
AZ. Northerly flow will quickly ramp up over the northern coastal
waters and by Friday evening models are showing solid gale force
winds. The northerly flow will also impact the western portions of
SLO and SB Counties, generating some gusty Sundowner winds and
downslope warming off the Santa Lucia and Santa Ynez Ranges Friday
into Friday night. Will certainly be needing wind advisories
across those areas with around a 30-40% chance of gusts to around
60 mph (warning level) in the more favorable north wind areas such
as the hills above Montecito. At the same time models show very
warm temperatures developing during the evening and overnight
periods and this looks like a situation where temperatures stay in
the 80s and possibly even low 90s throughout much of the night in
the Santa Ynez Range and even down into the coastal plain.
Advisory level winds also expected across the northern Ventura
mountains and the Grapevine areas. Some of those winds will filter
down into the LA valleys but probably not stronger than 30 mph.

Marine layer stratus will quickly dissipate from the north Friday
and most areas should see much earlier clearing. By Saturday
morning stratus coverage will either be zero or just minimal
clouds across the coast from LA to Ventura county. Saturday will
be a much warmer day for most areas. Warmest locations will be in
the Sundowner areas where highs in the 80s and lower 90s are
likely, even at some beach areas in SLO and SB Counties. This may
require the issuance of heat advisories for parts of the Central
Coast and southern Santa Barbara County with highs 15-20 degrees
above normal. Elsewhere, warmer valleys also expected to be in the
90s and coastal areas in the 70s to lower 80s.

Another round of warm and gusty Sundowner winds are expected
Saturday night.

.LONG TERM (SUN-WED)...12/230 PM.

Sunday will be an interesting day as there will still be strong
northerly winds continuing across the western counties, adjacent
coastal waters, and the northern mountains. However, models have
been consistent showing the development of a coastal eddy
circulation developing off the coast of LA and Orange Counties and
significant cooling at least for LA/Ventura County coast and
valley areas. And most of the models are even showing several
degrees of cooling across inland areas of LA/Ventura Counties as
well. Will likely still see advisory level Sundowner winds again
Sunday into Monday for the Santa Barbara area but probably not
quite as warm as the previous couple days. With the eddy
developing later in the weekend will likely see marine layer
stratus moving up from the south and into coastal LA/Ventura
Counties.

Northerly flow expected to remain quite strong across the offshore
coastal waters through the middle of next week, which will keep at
least a threat of Sundowner winds going for southern Santa Barbara
Counties going into next week as well. For this reason, stratus
coverage should be confined to just LA/Ventura Counties at least
for the first half of the week. Temperatures in these areas will
drop back to normal or slightly below normal levels.

For SLO and northern Santa Barbara Counties, gusty northwest winds
will continue, especially near the coast, but little or no marine
layer stratus is expected. Temperatures will generally be within a
few degrees of normal.
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&&

.AVIATION...
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13/0038Z.

At 2233Z at KLAX, the marine layer was 1300 ft deep. The top of
the inversion was at 3200 ft with a temperature of 24 C.

High confidence in desert TAFs.

Low to moderate confidence in all other TAFs due to uncertainty in
CIG heights and timing of flight cat changes (which could be off
by +/- 2 hours). There is a 40% chance that KPRB could remain VFR
through the period. There is a 30% chance that KSMX could lower
to LIFR 07-15Z. DZ possible at all TAF sites (except desert) late
night into morning. There is a 30-40% chance of IFR conds for LA
coastal TAF sites and KBUR/KVNY 09Z-15Z.

KLAX...Moderate confidence in TAF. There is a 40% chance of BKN008
cond 09Z-15Z Thu. Any east wind component should remain weaker
than 7 kt.

KBUR...Moderate confidence in TAF. There is a 40% chance of BKN008
conds 09Z-15Z Thu.
-- End Changed Discussion --

&&

.MARINE...12/125 PM.

In the outer waters, high confidence in the forecast. Winds and
seas are expected to remain below Small Craft Advisory (SCA)
levels thru Thu afternoon, then an extended period of strong NW
winds is likely. SCA winds will occur starting Thu night,
increasing to Gale Force Friday afternoon with Gales continuing
into Monday afternoon. SCAs and Gale Watches have been issued.
There is even a 20-30% chance of STORM Force wind gusts (to 48 kt
or greater) at times Fri night thru Sun night, mainly during the
evening hours.

In the inner waters N of Pt. Sal, conditions will likely remain
below SCA levels thru Fri morning. SCA conds are likely (80% chance)
Fri afternoon thru Sun night. Winds may drop below SCA levels for
a few hours during the late night thru morning hours, but seas will
likely remain at or above SCA levels. There is a 40-50% chance of
Gale force winds during the afternoon/eve hours Sat and Sun.

In the Santa Barbara Channel, conds will likely remain below SCA
levels thru Thu afternoon. There is a 30% chance of SCA level
winds in western portions Thu night. SCA level winds are likely
(80% chance) across western portions of the SBA Channel during
the late afternoon thru late night hours Fri thru Sun, with a 40%
chance of Gale force winds during these hours Sat and Sun. In the
eastern portion of the SBA Channel, SCA conds are likely (60-70%
chance) during the late afternoon thru late evening hours Fri thru
Sun. Steep waves of 8 to 12 ft are likely late Fri thru Mon.

In the southern inner waters, forecast confidence is lower. There
is a 30% chance of SCA level W-NW winds in northwestern portions
Fri afternoon/evening, and a 60% chance of SCA conds Sat afternoon
thru Sun night, mainly from Anacapa Island to Malibu. There will
likely be steep and dangerous seas, possibly to SCA levels Sat-Mon.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 2 AM to 2 PM PDT Friday
      for zones 670-673-676. (See LAXMWWLOX).
     Gale Watch in effect from Friday afternoon through Monday
      afternoon for zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Smith
AVIATION...Lund
MARINE...DB/Cohen
SYNOPSIS...MW/Smith

weather.gov/losangeles

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