165
FXUS66 KLOX 160540
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1040 PM PDT Mon Jul 15 2024

.SYNOPSIS...15/145 PM.

There is a chance of thunderstorms this afternoon over the Los
Angeles and Ventura County mountains and Antelope Valley,
otherwise skies will be clear except for morning low clouds across
the coasts. A cooling trend will continue through Tuesday, but a
warming trend starting Wednesday will lead to the possibility of
extreme heat across the interior by the weekend and into next
week.

&&

.SHORT TERM (MON-THU)...15/846 PM.

Only a couple of convective storms as atmosphere continues to
gradually dry out in the short term. Chances for convection
continue to drop Tuesday and for now am keeping storms out of the
official forecast. At this point, model cross sections and
soundings showing just enough moisture and instability
for some afternoon buildups on Tuesday over the local mountains.
By Wednesday, there is slightly better moisture transport into the
mountains, with some lingering instability. At this point,
probably just a 5-10 percent chance of thunderstorms for the
eastern San Gabriels and northern Ventura county mountains for
Wednesday afternoon, but this may need to be edged up a bit
as we get closer.

Forecast for tomorrow and the rest of the week remains mostly
unchanged. This current "cooler" pattern will continue another day
or two before the upper high retrogrades back west and the warming
trend returns. Highs in the warmer valleys by Thursday expected to
reach the mid to hi 90s and around 105 across the interior,
including inland SLO County. Not quite to excessive heat levels
but those are expected later in the week. High res models continue
to indicate fairly minimal coverage of low clouds and fog outside
of the Central Coast, but with more stable air aloft and
decreasing PW`s there may be a little more stratus then there has
been lately.

Some localized sundowner winds occurring across southwest
Santa Barbara county this evening, with current Santa Barbara-
Santa Maria gradient at -3.2 mb. Winds will be strongest
near Gaviota/Refugio this evening, with localized gusts of
35 to 45 mph in the hills. Sundowner winds are expected to be
slightly stronger and more widespread on Tuesday and Wednesday,
potentially reaching advisory levels. For each late afternoon
and nighttime period, the sundowner winds are expected to mostly
be focused across the western portions of the Santa Ynez range
and south coast.

.LONG TERM (FRI-MON)...15/221 PM.

Dangerous heat levels are possible later this week through at
least early next week as high pressure aloft returns and onshore
flow weakens. Like the last couple heat waves, this one will again
focus across the interior areas, including Antelope Valley,
Mountains, Interior SLO/SB where highs are expected to be 8-12
degrees above normal. Temperatures reaching 110 or higher are
possible (30-40% chance) once again in these areas starting
Saturday, though Excessive Heat warnings and/or heat advisories
could be needed as soon as Friday. Warmer coastal valleys could
reach 105. Coastal areas will be moderated by the cool ocean temps
but even there highs expected to reach the upper 70s and 80s.

As the high shifts back west it will also bring with it increasing
moisture from the southeast leading to possible thunderstorms
across the mountains and deserts and a non-zero chance of
convection at lower elevations as well.

&&

.AVIATION...15/2326Z.

At 17Z at KLAX, the marine layer was 1100 feet deep. The top of
the inversion was at 3500 feet with a temperature of 28 deg C.

High confidence in TAFs for KPRB, KPMD, and KWJF. There is a 10%
chance KPRB becomes IFR between 12 and 15Z. There is a 15% chance
of thunderstorms thru at KPMD and KWJF this afternoon through
evening (03Z).

High confidence in KBUR and KVNY. There is a 10% chance of
IFR/LIFR conditions at KBUR and KVNY between 10Z and 15Z.

Low confidence in coastal TAFs. Flight category changes may be
off +/- 3 hours. VFR conditions likely at most coastal sites
through the afternoon, with conditions becoming IFR at most sites
tonight. There is a 20-30% chance of LIFR conditions at KSBA,
KOXR, and KCMA between 08-14Z.

KLAX...Moderate confidence in TAF. Cigs between 800 and 1000 feet
likely to arrive after 06Z and persist thru at least 17Z. There
is a 10% chance of cigs below 500 ft and/or vsbys below 3SM
between 09-15Z. Flight category changes could differ +/- 2 hours.
No significant east wind component expected.

KBUR...Moderate confidence in TAF. There is a 10% chance that
cigs and vsbys could arrive between 10 and 15Z. Cigs below 500ft
and vsbys below 3SM would be likely if they reach the valley.

&&

.MARINE...15/1039 PM.

In the southern outer waters (zones PZZ673 and PZZ676), the
current Small Craft Advisory (SCA) looks on track, ending tonight.
Expecting winds to fall below SCA levels overnight, likely
redeveloping in the southern two outer zones (PZZ673/676) Tuesday
afternoon/night thru Wednesday morning. Higher confidence in SCA
Wednesday afternoon thru at least Saturday night.

In the northern zone (PZZ670), there is a 30% chance of SCA winds
beginning Wednesday afternoon. SCA winds become likely (70%)
beginning Thursday and will likely last thru at least Saturday
night.

In the inner waters N of Pt. Sal (Zone PZZ645), SCA conditions
are not expected thru Wednesday. There is a 30% chance of SCA
conditions beginning Thursday afternoon and persisting in the
afternoon/evening hours thru at least Saturday.

In the inner waters S of Pt. Conception, today, SCA level winds
affected a good portion of the Santa Barbara Channel. Current
guidance suggests winds will be stronger Tuesday evening,
spreading to the Ventura County Coast. Therefore, SCA winds are
expected to redevelop Tuesday afternoon/evening in the Santa
Barbara Channel, especially over western portions and near the
Channel Islands and will likely need a short-lived SCA for this
timeframe. There is a 20-40% chance of SCA winds in the afternoon
and evening hours Wednesday thru at least Saturday night. SCA
conds are not expected thru the forecast period for Zone PZZ655.

&&

.BEACHES...15/1010 PM.

A series of Southern Hemispheric storms will send a long-period,
S to SW swell (around 18-second wave periods) to the Southern
California coastal waters during early to middle parts of this
week. Wave periods will gradually shorten to around 15 seconds by
late week. This south to southwest long-period swell will bring an
extended period of elevated surf -- surf heights of 4-6 feet --
along with powerful and dangerous rip currents (over 80% chance)
from Tue thru Thu. The area of greatest concern for these impacts
will be on beaches with highest exposure to a S to SW swell
directions -- especially on the L.A. and VTU County beaches. These
factors warrant the issuance of a Beach Hazards Statement for the
beaches of L.A. and VTU Counties.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect from 9 AM PDT Tuesday
      through Thursday evening for zones 354-362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/MW
AVIATION...Lewis
MARINE...Phillips/Lewis
BEACHES...Phillips/Cohen
SYNOPSIS...MW

weather.gov/losangeles

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