243
FXUS66 KLOX 062133
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
233 PM PDT Sat Jul 6 2024

.SYNOPSIS...06/214 PM.

A long-lasting and extreme heatwave will continue across the
region, and especially the interior, through much of next week.
There is a high risk for dangerous heat illness and fast-growing
fires. High temperatures will reach 105 to 115 across interior
valleys, mountains and deserts. Dense fog may develop across some
beaches during the night and morning hours.

&&

.SHORT TERM (TDY-TUE)...06/210 PM.

Low clouds lingered early this afternoon for many coastal areas,
and there were areas of smoke coming off the Lake Fire in the SBA
County mtns. Otherwise, sunny skies covered the forecast area
with little change expected the rest of today.

The marine inversion has been low and strong today, but under the
inversion there has been a broad southerly flow over the SoCal
bight into VTU/L.A Counties. This along with a quickly increasing
onshore flow has brought cooler temps to the inland coast and
adjacent vlys early this afternoon. There has been enough cooling
that many of the Heat Advisories and Excessive Heat Warnings for
these areas have been cancelled. The same goes for the inland
Central coast to the Santa Ynez Vly. However, high heat has been
affecting the interior vlys to the mtns and deserts early this
afternoon with temperatures soaring into the 105 to 115 degree
range and Excessive Heat warnings continue there.

A 598 dam H5 upper level high over nrn CA early this afternoon
will slowly build S and into srn CA thru Mon. This upper level
high will keep very hot conditions continuing for the next several
days over the interior vlys to the mtns and deserts, where
Excessive Heat Warnings will continue. Please see the latest Non-
Precipitation Weather Message (LAXNPWLOX) for further details on
the current warnings.

For the coast and adjacent vlys, good onshore flow will keep
temps from getting excessively hot, but will still be several
degrees above normal. Pressure gradients will be quite strong
onshore Sun then turn slightly weaker for Mon. By Tue, pressure
gradients should be somewhat weaker and allow temps to warm up
again for the vlys, where Heat Advisories may be needed.

As far as cloud cover, varying amounts of night and morning low
clouds and fog will affect mainly the coast some inland
penetration to a few adjacent vlys. Patchy dense fog will also be
possible the next couple of nights along the Central Coast.
Otherwise and elsewhere, mostly clear skies can be expected,
except for areas of smoke from the Lake Fire in the short term
over portions of SLO/SBA Counties.

.LONG TERM (WED-SAT)...06/213 PM.

The GFS and EC are in generally good agreement in the extended
period. The large and strong upper level high will slowly push
into srn NV for Wed then linger in this general area into Thu. The
upper level hi will then move more into the Four Corners region
for Fri and Sat. Srn CA will be under the western and southwestern
periphery of the upper level hi thru Fri, then a weak upper level
trof will develop along the CA coast for Sat.

The Central Coast is expected to have night and morning low
clouds and fog thru the period, with varying amounts of low clouds
and fog S of Point Conception, primarily on the L.A./VTU County
coast at times as a northerly flow over the Santa Ynez range
should keep the SBA County S coast free of the low clouds. Low
clouds may persist at some of the Central Coast beaches each
afternoon as well. Otherwise, mostly clear skies are expected for
Wed thru Sat.

Excessive heat is expected to continue Wed and Thu, especially
for the interior vlys to the mtns and deserts, and existing
Excessive heat Warnings which run thru Wed for these areas may
need to be extended into Thu. It also looks like Heat Advisories
or even Excessive Heat Warnings may be needed for the vlys and
Santa Ynez Mtns Wed and Thu as temps heat up due to to weaker
onshore flow.

Temps should cool down enough for Fri and Sat due to stronger
onshore flow to the N and E that the only areas that may need heat
products would be the L.A. County mtns and deserts. Even with
cooler temps for the coast and vlys, it will still be several
degrees above normal each day.

&&

.AVIATION...06/1937Z.

At 18Z at KLAX, the marine layer was 1500 feet deep. The top of
the inversion was at 4200 feet with a temperature of 35 deg C.

Strong eddy circulation has caused the marine layer to deepen,
and clouds to expand into all coastal areas south of Point
Conception. Cigs were most entrenched across L.A, County, where
clouds were just dissipating in the San Gabriel Valley. Cigs were
mostly in the IFR to LIFR categories, with local VLIFR conds.
Expect cigs to slowly clear this afternoon, except linger near the
beaches from southern SBA County to L.A. County thru the
afternoon.

Expect widespread low clouds in all coastal areas tonight, with
clouds pushing into the San Gabriel and Santa Ynez Valleys by late
evening, and likely pushing into the San Fernando Valley and
lower valleys of Ventura County late tonight. Conds will be mostly
IFR to LIFR, with local VLIFR conds north of coastal sections of
L.A. County and in the valleys.

KLAX...Low confidence in the 18Z TAF. There is a 30% chance that
cigs will linger thru 23Z. There is a 30% chance that cigs will
arrive as early as 01Z or as late as 06Z this evening. There is a
30% chance that cigs will rise into the MVFR category as early as
11Z tonight. There is a 20-30% chance that the east wind of 7 to
9 kt will persist thru 22-23Z. There is a 20% chance of at east
wind component of 7-8 kt from 10Z-16Z.

KBUR...Moderate confidence in the 12Z TAF. There is a 30% chance
that IFR or LIFR cigs will arrive as early as 09Z tonight.

&&

.MARINE...06/231 PM.

In the Outer Waters, Small Craft Advisory (SCA) level winds have
dropped below SCA levels in all areas.

For the most part, expect winds to remain below SCA levels
tonight and Sun morning, then close to but just below SCA levels
Sun afternoon thru Thu. There is a 30% chance of SCA level NW
winds in the far outer waters and from near Pt. Conception to NW
of San Nicolas Island during the late afternoon thru late evening
hours each day Sun thru Thu.

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 Wed night.

In the inner waters south of Pt Conception, SCA conditions are
not expected thru Thu. However, there is a 30% chance of SCA
winds during the afternoon/evening hours Tue thru Thu in western
portions of the Santa Barbara Channel, mainly from Santa Cruz
Island to the SBA County south coast from Pt. Conception to
Gaviota to Refugio State Beach.

Areas of dense fog will continue to affect the coastal waters
through Sun morning. Please reference the Marine Weather
Statement for additional information.

&&

.BEACHES...06/233 PM.

A moderate southerly swell will affect the Southern California
coastal waters through Sunday, with a 15-17-second period this
weekend. While surf is not expected to be particularly high, surf
heights of up to 4 to 6 feet are anticipated at beaches exposed to
southerly swell, especially the LA and Ventura County beaches.

Significant wave energy with the long-period swell will combine
with the elevated surf to create dangerous conditions at area
beaches, with powerful and dangerous rip currents expected. This
is especially the case for the south-facing beaches of LA and
Ventura Counties. A Beach Hazards Statement is in effect through
Sunday evening to address these concerns.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning remains in effect until 9 PM PDT
      Wednesday for zones 38-343>345-353-376>379-381>383. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect until 9 PM PDT
      Sunday for zones 88-351-352-375-380. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Sunday 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...Sirard
AVIATION...DB
MARINE...DB
BEACHES...DB
SYNOPSIS...Sirard

weather.gov/losangeles

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