709
FXUS66 KLOX 241700
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1000 AM PDT Mon Jun 24 2024

.SYNOPSIS...24/224 AM.

Dangerously hot weather will continue away from the coast
especially over the Antelope Valley. Elsewhere, there will be a
gradual cooling trend through the week. There is a slight chance
of thunderstorms today over the mountains and SLO county.

&&

.SHORT TERM (TDY-WED)...24/959 AM.

***UPDATE***

We continued to track showers and isolated thunderstorms near the
Central Coast, which should move northeast towards interior areas
this afternoon to early evening. Main potential impacts are
expected to be cloud-to-ground lightning including potential fire
starts (dry lightning) and potentially damaging wind gusts of 50+
mph with any stronger thunderstorms. Storms will be moving slow,
with any stalled storms potentially leading to flood concerns,
focused across the mountains.

Challenging temperature forecast today as mid level clouds
continue to interrupt the typical marine influence across the
region and especially coastal areas. High temperatures should be
cooler most areas, especially coastal areas of Ventura and Los
Angeles Counties where moderate onshore trends should support an
earlier and stronger sea breeze. The cloud cover led to warm
overnight lows nearing 80 in some high deserts, which increases
heat impacts for those areas, and warrants the continuation of
heat products away from the coast, despite slightly cooler
daytime highs.

With the afternoon forecast package we will continue to watch
convective chances over the next day or so and examine the need
for heat products over th next couple of days.

***From Previous Discussion***

A lobe of PVA currently south of the Channel Islands is moving
from S to N. It has a few embedded showers in it and will bring a
slight chc (15 percent) of a shower or TSTM to the Channel
Islands, The Santa Barbara Channel and SBA county this morning.
Otherwise skies will be partly cloudy as debris clouds float
overhead. Only very minimal marine layer clouds today as the
clouds and humidity aloft have greatly disrupted the stratus
formation. The onshore flow this afternoon will be about 3 mb
strong than ydy and this will bring noticeable cooling to the
coasts and vlys. 591 dam hgts however will continue to bring the
heat to the interior. The vlys will not be warm enough for heat
advisories and these were cancelled. A heat warning was added for
the Western Antelope Foothills where triple digit heat will occur.
One more day of heat advisories for the interior of SLO and SBA
counties as there will be little or no change in temps from ydy`s
readings. Mid level moisture will combine with afternoon solar
induced instability over the mtns to bring a slight chc (20
percent) of TSTMs to the higher peaks of the LA/VTA mtns. This
morning`s vort lobe will be over SLO county this afternoon and
will also generate the same slight chc of TSTMs.

The strong onshore push will likely generate more coastal low
clouds tonight but given how disorganized the marine layer is now
it will likely take much longer for the clouds to develop. The
upper high will shift a little to the SW and this will bring dry
SW flow over the area and squash the risk of convection. Most
cst/vly locations away from the beaches will cool 2 to 5 degrees
and will end up 3 to 6 degrees above normal. The Antelope Vly will
continue to sizzle under 593 dam hgts and the heat warning will
persist there.

An upper will will move through the PAC NW on Wednesday. Weak
troffing will move over CA and hgts will drop to 588 dam. Onshore
flow will remain strong and there will be more and earlier
arriving marine layer stratus. The beaches will see slower
clearing. Most areas will cool 2 to 4 degrees which may be enough
over the Antelope Vly to end the Heat Warning early. The csts/vlys
will cool to near normal while the inland areas will end up 4 to 6
degrees above normal.

.LONG TERM (THU-SUN)...24/322 AM.

Both the EC and GFS as well as most of their respective ensembles
have trended away from their rather dire heat predictions they
both had earlier. Now the xtnd fcst looks pretty static. The upper
high will migrate to the east while a fairly stationary troffing
pattern sits over the west coast. This will keep dry SW flow over
the area and eliminate any convective threat. The marine layer
will be very shallow and may behave as it has lately with hardly
any inland penetration.

Max temps will slowly fall through Saturday as hgts fall. By
Saturday max temps will be 2 to 4 degrees blo normal. Onshore flow
will weaken some on Sunday and this will bring a few degrees of
warming to the area.

&&

.AVIATION...24/1646Z.

At 16Z over KLAX, the marine layer was 600 feet deep. The top of
the inversion was 3500 ft and 24 degrees Celsius.

There is a chance of -TSRA today: 20% chance at KSBP 16-19Z, KPRB
17-22Z, KWJF KPMD 20-02Z...10% chance KSBP KPRB 00-04Z. All other
sites have a low (5%) but non zero chance. Any thunderstorm will
likely produce brief gusty winds and little if any rain. There is
a chance of IFR/LIFR conditions tonight into Tuesday: 40% chance
at KSMX, 20% chance at KSBP KSBA, 10% chance at KOXR KSMO KLAX
KLGB. Otherwise, high confidence in VFR conditions into Tuesday.

KLAX...There is a 10% chance of IFR/LIFR conditions after 08Z
tonight. There is a 5% chance of -TSRA through early Tuesday, with
higher chances over the nearby mountains and deserts. Otherwise,
high confidence in VFR conditions. High confidence that any
southeast winds will remain under 8 knots.

KBUR...There is a 5% chance of -TSRA through early Tuesday, with
higher chances over the nearby mountains and deserts. Otherwise,
high confidence in VFR conditions.

&&

.MARINE...24/946 AM.

The threat of isolated thunderstorms will remain today, and
possibly through Tuesday as moisture from the remnants of Tropical
Storm Alberto linger over the region. With dry air near the
surface, any storm can product brief but very gusty winds.

Dense fog with visibilities under one mile will remain a concern,
and while the coverage and shrunk a lot, expect some random
patches tonight into Tuesday.

There is a 30 percent chance of Small Craft Advisory (SCA) level
wind gusts tonight and Tuesday Night for the Outer Waters
(offshore waters of the Central Coast to San Nicolas Island).
Otherwise, high confidence in weaker than usual winds for this
time of the year. Northwest winds will increase Wednesday
afternoon through Thursday night. High confidence in SCA level
winds and steep seas for the Outer Waters. 50 percent chance for
SCA winds and seas for the nearshore Central Coast waters, and a
20 percent chance for the western Santa Barbara Channel.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect until 8 PM PDT this evening
      for zones 38-344-345-348-353-379. (See LAXNPWLOX).
     Excessive Heat Warning in effect until 8 PM PDT this evening
      for zone 381. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect until 8 PM PDT
      Thursday for zones 382-383. (See LAXNPWLOX).
PZ...NONE.

&&

$$

PUBLIC...Rorke/RM
AVIATION...Kittell
MARINE...RK
SYNOPSIS...30

weather.gov/losangeles

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