932
FXUS66 KLOX 232325
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
425 PM PDT Sun Jun 23 2024

.SYNOPSIS...23/117 PM.

Dangerously hot weather will continue away from the coast as high
pressure aloft remain in place across much of the southern United
States. There will be a gradual cooling trend over many locations
during the upcoming week, except for the Antelope Valley where
conditions will stay very hot into mid- week. There is a slight
chance of a few thunderstorms through tonight.

&&

.SHORT TERM (TDY-WED)...23/136 PM.

Temperatures within the coastal margin have warmed significantly
today compared to yesterday thanks in part to the marine layer
being disrupted by mid level moisture and associated clouds.
Excessive heat products with moderate to high heat impacts
continue through this evening away from the immediate coast,
except for through Thursday for the Antelope Valley. We will
likely need to extend heat products for some interior areas into
early next week, probably at just the advisory level as at least
some cooling is expected.

The moisture associated with the mid cloud deck continue to
support a 5-15 percent chance (highest across the interior
mountains) of a thunderstorm across the region today with
afternoon cumulus and a shower or two already showing up along the
high terrain. Dangerous cloud- to- ground lightning and damaging
wind would be the main concerns should a stronger thunderstorm or
two form with climatologically favored areas for this being the
eastern San Gabriel mountains into the Antelope Valley and Ventura
mountains west to the Santa Barbara mountains (excluding the
Santa Ynez Range). Generally weak flow aloft would likely support
slow storm movement towards the north or northeast around 10 mph
with anchoring or back building along the high terrain possible.

A reorientation of the flow aloft to the southwest to west and
departure of mid level moisture should support increased and
breezy onshore winds Monday into Tuesday, supporting the
aforementioned cooling trend most notable for coasts and coastal
valleys. The marine layer may struggle to form clouds for a day or
two for Los Angeles, Ventura, and Southern Santa Barbara
Counties. Where low clouds do form, patchy dense fog will be
possible through at least Monday as the ridge aloft keeps a
shallow marine layer in place.

.LONG TERM (THU-SUN)...23/132 PM.

Only moderate confidence in the extended period as there is a
60-70 percent chance for significant rebound in the heat (as hot
if not hotter for many areas) next weekend. Similar to the ongoing
heat, the marine layer will probably somewhat limit the heat and
related impacts near the coast. Low to moderate heat risk will
continue Thursday through Friday or Saturday, before potentially
increasing to moderate to high levels next weekend. If the higher
heat scenario plays out, there may be a AVDAFDLOXmonsoon push into at least
Los Angeles County towards the end of the weekend or into early
next week. Breezy northwest to onshore winds will continue,
potentially nearing advisory levels for southwest Santa Barbara
County in particular late in the week.

&&

.AVIATION...23/2324Z.

At 0000Z at KLAX, the marine layer was 800 feet deep. The top of
the inversion was at 2200 ft with a temperature of 30 deg C.

Low to moderate confidence for all sites in Santa Barbara and San
Luis Obispo Counties. Monsoonal moisture moving over the area
will bring a 10-15 percent chance of a thunderstorm affecting the
airports during the overnight period through 12Z. In addition
there is low confidence in the low cloud forecasts for KSBA, KSMX
and KSBP as the monsoonal flow may disrupt the marine layer,
resulting in no low cloud formation.

Otherwise, moderate confidence in the remainder of the coastal
TAFs, and high confidence for the LA County valley and desert
sites. The timing of low clouds arrival along the coast is low
confidence.  and there is a 30 percent of no cloud cover
overnight.

KLAX...Moderate confidence in the 00Z TAF. The arrival time of low
cigs could differ by +/- 2 hours from TAF time, and there is a 30
percent chance of no low clouds. There is a 10 percent chance of
SHRA or TSRA through 06Z. Good confidence that any east wind
component will be under 5kt.

KBUR...High confidence in the 00Z TAF. There is a 15 percent
chance of SHRA or TSRA through 06Z.

&&

.MARINE...23/128 PM.

For the Outer Waters, high confidence in current forecast. Conds
will likely remain below Small Craft Advisory (SCA) levels through
Wednesday morning. NW winds are forecast to increase to SCA levels
Wednesday afternoon then linger for much of the time through
Friday night.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Conds will likely remain below SCA
levels through Wednesday morning. SCA level wind gusts are then
expected mainly afternoon and evening hours Wednesday afternoon
through Thursday. There is then a 30% chance of SCA level wind
gusts Friday afternoon and evening.

For the inner waters south of Point Conception, moderate to high
confidence in current forecast. SCA winds are not expected over
most of the area through Friday night, except for the western
third of the Santa Barbara Channel where there is a 40% chance of
SCA level wind gusts mainly afternoons and evenings Wednesday
through Friday.

There is a slight chance of thunderstorms mainly over the
northern waters through this evening. In addition, areas of dense
fog will likely continue at times through early this week. Please
see the Marine Weather Statement (LAXMWSLOX) for information of
the thunderstorm potential, as well as the potential for dense
fog.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect until 8 PM PDT this evening
      for zonesAVDAFDLOX
      38-88-341>345-347-348-351-352-355>358-368>375-380-548. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect until 8 PM PDT this
      evening for zones 353-376>379-381. (See LAXNPWLOX).
     Excessive Heat Warning remains in effect until 8 PM PDT
      Thursday for zones 382-383. (See LAXNPWLOX).
PZ...NONE.

&&

$$

PUBLIC...Munroe
AVIATION...Smith
MARINE...Sirard
SYNOPSIS...Hall/RS/RM

weather.gov/losangeles

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