535
FXUS66 KLOX 280353
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
853 PM PDT Thu Jun 27 2024

.SYNOPSIS...27/828 PM.

Slight cooling is expected into Friday as high pressure aloft
weakens. Gusty northwest winds will affect southwestern Santa
Barbara County and the Interstate 5 Corridor tonight. Warmer
weather is expected over the weekend as high pressure returns, and
above normal temperatures will continue through next week.

&&

.SHORT TERM (THU-SUN)...27/107 PM.

Synoptically, the area is still under the western portion of a
593 dam high centered over southern New Mexico. To our north, a
559 dam low is trekking roughly along the US/Can border. By
Saturday the low will make it to the Great Lakes region and the
high begins to build back in over northern Texas. While this high
pushes in from the east, by Tuesday the eastPac 597 dam high
begins to approach us from the west. Higher heights look to
remain over most of California through the extended in what may be
a prolonged heat event.

Skies are mostly clear except for the coast in the southern
portion of the central coast. Temps are down 3-5 degrees in most
locations except for the coastal strip along the SBA south coast
through Long Beach that saw some extra sunshine this morning.

N-S gradients are forecast to increase very slightly across SBA
County tonight, so expect another round of low-end wind advisory
level NW winds across the western portions of the south coast of
SBA County and the western Santa Ynez Range. Have issued wind
advisories there for late this afternoon thru late tonight. Gusty
winds thru the I-5 Corridor will also return tonight but should
stay below advisory levels. Expecting more widespread low
clouds tonight, affecting most coastal areas (with the exception
of the S coast of SBA County due to the N flow).

on Friday a weak short wave trough will approach the West Coast.
Heights will actually fall a bit, as will temps at 850/950 mb.
Should stratus become widespread Fri morning, clouds may linger
into the afternoon, especially near the coast. Max temps may be
down a couple of degrees in most areas on Fri.

Heights will begin to rise across the region on Saturday as a
large upper high over the southeastern U.S. gradually expands
westward. There should be areas of low clouds and fog in coastal
and some lower valley areas Sat morning, but clearing should be
rather quick. Height rises and warming at 950 mb should bring
several degrees of warming in most areas Sat, especially away from
the coast. The best warming will likely be in the valleys as the
marine inversion lowers, decreasing the marine influence there.
High temps may rise well into the 90s in the warmest locations in
the valleys of L.A. County on Sat. Gradients should be steep
enough for some gusty winds in southwestern SBA County and thru
the I-5 Corridor Sat night, possibly to advisory levels.

The upper high will continue to expand westward on Sunday causing
heights to rise. Onshore flow will weaken, and the marine layer
will become increasingly shallow. Low clouds Sunday morning
should be confined to locations within a few miles of the coast.
Max temps will likely exceed 100 degrees in the Antelope Valley,
Paso Robles and the interior valleys of SLO County, with highs
near 100 degrees in some of the warmer locations in the valleys of
VTU/L.A. Counties. Gradients could again drive near advisory
strength gusty wind in southwestern SBA County and thru the I-5
Corridor.

.LONG TERM (MON-THU)...27/114 PM.

Heights will change little from Sunday into Monday so expect only
minor changes in night/morning low cloud coverage and temperatures.

There is still uncertainty in the forecast, but ensembles include
the possibilty of developing the upper high in the eastern
Pacific on Tuesday through at least Thursday, with high heights
across the region, and continued hot, to very hot, weather -
especially across the interior where temperatures could exceed
100-105 degrees. There is growing concern that this could become a
potentially hazardous heatwave with impacts around the 4th of
July.

&&

.AVIATION...28/0017Z.

At 2314Z over LAX, the marine layer was 900 feet deep. The top of
the inversion was 5300 feet and 24 degrees Celsius.

High confidence in VFR conditions through Friday at KPRB KWJF
KPMD. All other sites with the exception of KSBA have a chance of
ceilings tonight into Friday. Best chances for cigs at KSMX,
KLAX, KSMO and KLGB. If cigs reach KBUR and KVNY, clouds will
likely be brief. Expecting mostly MVFR to IFR conditions, however
brief LIFR conditions are possible at KSMO, KLAX, and KLGB.

KLAX...Moderate confidence in VFR conditions through 09Z. Low to
moderate confidence in cigs tonight, with potential for brief cigs
around 02Z. Cigs may arrive as early as 09Z, and become more
likely after 12Z. There is potential for an east wind component
up to 6 kt from 10 to 15Z, with high confidence it will remain
under 8 kt.

KBUR...Low confidence in IFR to MVFR cigs arriving after 12Z
tonight. Cigs will likely be short-lived if they do occur. High
confidence in seasonal winds.

&&

.MARINE...27/833 PM.

There is a moderate threat of dense fog late tonight into Friday
for the waters along the Central Coast.

Moderate confidence in low-end Gale conditions for the outer waters
from the Central Coast to San Miguel Island through late tonight.
There is a 20 percent chance of these Gales extending south to
San Nicolas Island, otherwise high confidence in Small Craft
Advisory (SCA) winds. SCA level west to northwest winds will push
into the Santa Barbara Channel as well but high confidence that
they will stay confined to the western half.

High confidence that winds will decrease each day Friday through
Saturday morning, but increase again Saturday afternoon into Monday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 3 AM PDT Friday for
      zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Friday for zone
      645. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Friday for zones
      670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Saturday for
      zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB/jld
AVIATION...Phillips/Lewis
MARINE...Kittell
SYNOPSIS...jld/Smith

weather.gov/losangeles

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