855
FXUS66 KLOX 041116
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
416 AM PDT Thu Jul 4 2024

.SYNOPSIS...03/127 PM.

A significant heatwave will affect the region this week and will
continue through much of next week, with dangerously hot
temperatures across much of the area. High temperatures will reach
95 to 105 degrees in many areas away from the coast, with highs
upwards of 105 to 115 over interior valleys and foothills,
including the Antelope Valley. Very warm to hot conditions could
extend closer to the coast by late this week. Patchy night to
morning dense fog will affect the coasts through at least
Thursday morning.

&&

.SHORT TERM (TDY-SAT)...04/415 AM.

An extended period of dangerously hot weather will continue across
much of the region into early next week. Not only will high
temperatures be dangerously high, but overnight temperatures will
remain elevated and limit any relief, especially for areas away
from the coast. This will be a time to limit exposure to the sun
(maybe even stay indoors) and make sure to stay hydrated.

The hot weather is a result of high pressure aloft continuing to
creep toward the West Coast and through Central California through
the weekend. Due to the high pressure, the marine layer influence
will be very shallow and remain limited to the coast through the
weekend allowing inland areas to warm up. However, there is a
small chance that clouds will linger at the beaches through the
day today and Saturday, but looks like it will clear out on Friday
due to weak northerly flow and offshore trends.

High temperatures today will increase a few degrees compared to
yesterday, but Friday is looking to have the biggest jump in high
temps with an increase of 5-15 degrees. The Santa Barbara South
Coast will warm 20 degrees due to northerly sundowner flow, except
lower at the immediate coast where a marine influence will most
likely prevail. Warmer coastal valleys will push close to 110 and
inland coastal areas in the 80s to low 90s. Deserts and other far
interior areas will be approaching or even locally exceeding 115.
These high temperatures will be up to 20 degrees above normal for
this time of year, and many daily record high temperatures may be
broken on Friday.

While Friday will be the hottest day with Saturday not far behind,
the duration of this event will likely produce an unprecedented
stretch of high temperatures over 110 degrees for the Deserts and
interior areas. The record for consecutive days at or above 110 is
three for Palmdale and Lancaster and five for Paso Robles. The
desert streak will almost certainly be crushed with the current
forecast showing highs over 110 for the next seven days.

.LONG TERM (SUN-WED)...03/214 PM.

Unfortunately, for many areas the extreme heat will continue well
into next week. Most of the ensemble solutions maintain a strong
high over the area at least through the middle of next week.
However, models are also indicating an increase in onshore flow
starting Sunday. While this should bring a few degrees of cooling
to coast and coastal valleys, with strong high pressure aloft it`s
unlikely this cooling will reach the interior. However, increasing
winds with the onshore push will reach the deserts, increasing
fire danger there with the continued extreme heat and hot and dry
air mass. The Excessive heat warning for the interior areas
(mountains, deserts, interior SLO/SB County) has been extended to
Wednesday and may need additional day beyond that. Coastal and
valley areas will be "cooler" but still 6-12 degrees above normal.

&&

.AVIATION...04/0022Z.

At 00Z at KLAX, the marine layer was 800 feet deep. The top of
the inversion was at 3600 feet with a temperature of 31 Celsius.

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

Moderate confidence in remainder of TAFs. For coastal locations,
expecting IFR-VLIFR cigs/vsbys due to fog and low clouds returning
tonight. Cig/vsby restrictions dissipating from late to early
afternoon Thursday. Timing of flight category changes may vary by
+/- 2-3 hours of current forecasts, and there is up to a 30%
chance for minimum flight categories to be off by at least one
category.

KLAX...Moderate confidence in TAF. VLIFR conditions due to fog,
with a 30% chance cigs/vsbys will be 1-2 hours off in arrival and
clearing times. No significant easterly wind component is
expected.

KBUR...High confidence in TAF.

&&

.MARINE...03/910 PM.

For the Outer Waters, Small Craft Advisory (SCA) conditions are
not expected through Thursday morning. Areas of SCA winds are
forecast to develop over PZZ673 and PZZ676 Thursday afternoon,
with SCA winds continuing into Saturday morning for PZZ676, and
continuing into Saturday night for PZZ673. There is a 60% chance
for SCA winds to occur across PZZ670 from Friday afternoon through
Sunday morning. There is also a 10-15% chance of local Gale Force
wind gusts for Friday afternoon and evening during the periods of
SCA winds across the Outer Waters.

For the Inner Waters north of Point Sal, SCA conditions are
generally unlikely through early next week, though there is a 30%
chance for SCA winds for Friday afternoon and evening.

For the Inner Waters south of Point Conception, SCA winds are
anticipated from Thursday afternoon through Thursday night across
a portion of the western Santa Barbara Channel. The area of
anticipated SCA-level NW-N winds is from Santa Cruz Island to the
Santa Barbara County coast from Point Conception to Gaviota to
Refugio State Beach. Within this area, there is also 10-15% chance
of local Gale Force wind gusts just offshore from the immediate
coast Thursday afternoon through Thursday night. There is also a
70% chance for SCA-level winds to reoccur in the Western portions
of the Santa Barbara Channel for Friday afternoon through Friday
night.

Dense fog is expected over the coastal waters for the remainder
of this week during the overnight to morning hours, with a
gradual decrease in the coverage of fog as the week progresses.
Please reference the Marine Weather Statement for additional
information.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning remains in effect until 6 PM PDT
      Wednesday for zones 38-343>345-353-376>379-381>383. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect until 6 PM PDT
      Monday for zones 88-342-348-351-352-356>358-369>375-380. (See LAXNPWLOX).
     Heat Advisory remains in effect from 11 AM this morning to 6
      PM PDT Sunday for zones 341-347-355-368. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect from 11 AM this
      morning to 6 PM PDT Saturday for zones 349-350. (See LAXNPWLOX).
     Beach Hazards Statement in effect from 11 AM PDT this morning
      through Sunday evening for zones 354-362-366. (See LAXCFWLOX).
     Heat Advisory remains in effect until 6 PM PDT Sunday for
      zone 548. (See LAXNPWLOX).
     Fire Weather Watch in effect from Friday morning through late
      Friday night for zones 342>345. (See LAXRFWLOX).
     Red Flag Warning in effect from 6 PM this evening to 6 AM PDT
      Saturday for zones 349-351>353-376>378-381. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 2
      AM PDT Friday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM Friday to 3 AM PDT
      Saturday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 9
      AM PDT Saturday for zones 673-676. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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