830
FXUS66 KLOX 072124
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
224 PM PDT Sun Jul 7 2024

.SYNOPSIS...07/224 PM.

A long-lasting and extreme heatwave will continue across the
mountains and interior areas through much of the coming week with
a high risk for dangerous heat illness and fast-growing fires.
Temperatures across coast and valleys have returned to normal
levels for now, however a warming trend is expected there through
the week with increasing risk of heat issues in the valleys.

&&

.SHORT TERM (TDY-WED)...07/156 PM.

An interesting day of temperatures across southwest California. A
vast majority of the area between SLO and LA Counties cooled since
Saturday. Most notably the areas around the Santa Clarita Valley
and the southern Salinas Valley where highs have been 15-20
degrees cooler. Cooling elsewhere was much more moderate but
noticeable. On the other hand much of LA Basin and the southern
portion of the Central Coast warmed by 3-6 degrees, likely a
result of earlier clearing of the low clouds.

For most areas except the far interior, high temperatures through
Wednesday are expected to warm at least a few degrees each day,
mostly due to weakening onshore flow and the return of some
northerly flow to southern Santa Barbara County and parts of the
northern mountains. Strong high pressure aloft will remain in
place through most of the week, keeping temperatures very hot
across the deserts and other far interior areas like the interior
SLO County and the mountains. The main change coming the next few
days is the return of weakening onshore flow which is the biggest
factor for warming west of the mountains. Except this time models
are not showing quite as much super hot air in the lower levels
so this round of heating for the valleys and coast will not be as
extreme as before, but still getting close to around 107 in the
warmest areas, such as the western San Fernando Valley and Santa
Clarita Valley. May need another round of excessive heat warnings
or heat advisories by Tuesday and lasting through Wednesday or
Thursday.

As the onshore flow weakens over the next few days the marine
layer will be clearing sooner, but may still hug the coastline
through the afternoon, especially LA/Ventura Counties. Developing
northerly flow along the Central Coast and southern Santa Barbara
County will likely limit or possibly eliminate the stratus in
those areas. Increasing north winds Tuesday and Wednesday evenings
in southern Santa Barbara County and parts of the Santa Lucias
may be strong enough for some wind advisories.

.LONG TERM (THU-SUN)...07/222 PM.

This very lengthy period of strong high pressure aloft only very
slowly weakens later this week into next weekend and deciding
which day to end the current slate of seemingly endless Excessive
Heat Warnings across the interior will be decided after
coordination with surrounding offices. For now have extended the
warnings there through Thursday which is about when high
temperatures start to reach or drop slightly below 110, but could
certainly see a case for going another day or two beyond that with
highs still 10-15 degrees above normal.

Similar situation for the valleys. There are no watches or
warnings currently in effect but the latest ensemble guidance is
leaning warmer and likely to stay 10-15 degrees above normal
through Thursday.

A slow cooling trend is expected to continue into next weekend,
however triple digit heat is possible in the valleys even into
next Sunday. Coastal areas will 2-5 degrees above normal Thursday,
then basically near normal next weekend with typical night and
morning low clouds and fog expected. Not really seeing any clear
signals of monsoon flow yet.

&&

.AVIATION...07/1800Z.

At 17Z at KLAX, the marine layer was 1600 feet deep. The top of
the inversion was at 4700 feet with a temperature of 31 deg C.

High confidence in VFR TAFs for KPRB, KVNY, KPMD, and KWJF.

Elsewhere, expect low clouds to scatter out or clear by late
morning for KCMA, and early this afternoon for KOXR and KSBA.
Expect widespread low clouds and fog tonight in all coastal
areas, and in portions of the Santa Ynez and San Gabriel Valleys
with mostly LIFR to VLIFR conds expected. KBUR has a 20% chance
of low clouds late tonight into early Mon morning.

Fires may lead to periods of smoke at some terminals today,
especially KSBA and north.

KLAX...Moderate confidence in the 18Z TAF. There is a 20% chance
that cigs will not arrive tonight until 06Z or later. Good
confidence in any east wind component remaining under 5 kts.

KBUR...Generally high confidence in the 18Z TAF. There is a 20%
chance of IFR cigs 10Z-15Z tonight and Mon morning.

&&

.MARINE...07/127 PM.

In the Outer Waters, winds are expected to remain below SCA
levels thru Mon morning. In the two northern zone (PZZ670/673),
SCA conds are likely (70% chance) Mon afternoon/evening, with a
40% chance of SCA conds at times Tue thru Thu night. In the
southern zone (PZZ676), SCA conds are not expected through Tue
morning. For all of the outer waters there is a 40% chance of SCA
levels winds Tue afternoon thru Thu night, mainly during the late
afternoon thru late night hours. Conds should be below SCA levels
Fri and Fri night.

In the inner waters N of Pt. Sal, there is a 30% chance of SCA
level winds during the afternoon/evening hours Mon and Tue,
otherwise SCA conds are not expected thru Fri night.

In the inner waters S of Pt Conception, SCA conditions are not
expected thru Fri night. The possible exception is in western
portions from Santa Cruz Island to the SBA County south coast from
Pt. Conception to Refugio State Beach, where there is a 30%
chance of SCA level winds during the late afternoon thru late
evening hours Tue thru Thu.

&&

.BEACHES...07/127 PM.

A moderately sized south swell with a 14 to 15 second period will
continue to affect the coastal waters thru this evening. This
will produce elevated surf of 4 to 6 ft on beaches exposed to
southerly swell, especially the L.A./VTU County beaches.
Significant wave energy and elevated surf will bring at threat of
powerful and dangerous rip currents. This is especially the case
for the south-facing beaches of L.A./VTU Counties, where a Beach
Hazards Statement is in effect.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning now in effect until 9 PM PDT Thursday
      for zones 38-343>345-351>353-376>383. (See LAXNPWLOX).
     Beach Hazards Statement in effect until 10 PM PDT this
      evening for zones 354-362-366. (See LAXCFWLOX).
     Red Flag Warning in effect until 6 AM PDT Monday for zones
      378-381. (See LAXRFWLOX).
PZ...NONE.

&&

$$

PUBLIC...MW
AVIATION...Sirard
MARINE...Sirard
BEACHES...DB/Sirard
SYNOPSIS...MW

weather.gov/losangeles

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