420
FXUS66 KLOX 272016
AFDLOX

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

.SYNOPSIS...27/116 PM.

Slight cooling is expected today and 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 (TDY-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...27/1614Z.

At 17Z over LAX, the marine layer was 800 feet deep. The top of
the inversion was 3500 feet and 25 degrees Celsius.

Moderate confidence in all sites staying VFR today through at
least 02Z. High confidence in VFR conditions through Friday at
KPRB KWJF KPMD. All other sites have a chance of ceilings tonight
into Friday: KSBP (40%) KSMX (60%) KSBA (50%) KOXR (70%) KCMA
(60%) KSMO (60%) KLAX (60%) KLGB (60%). High confidence that if
ceilings form, flight categories will be LIFR-IFR at KSMX KSBP
KSBA and IFR-MVFR elsewhere.

KLAX...Moderate confidence in VFR conditions through at least 04Z.
Low confidence on ceilings tonight. 60% chance of BKN008-012
starting as early 04Z and as late 12Z. Southeast winds will
likely form after 09Z, but high confidence that they will stay
under 8 knots.

KBUR...There is a 20% chance of IFR ceilings Friday 10-16Z,
otherwise high confidence VFR conditions through at least
Friday. High confidence in seasonal winds.

&&

.MARINE...27/906 AM.

Dense fog will impact the waters off the Central Coast this
morning, with reduced visibilities possibly lasting through the
afternoon and evening. There is a moderate threat for dense fog
again tonight into Friday for the same area.

Moderate confidence in low-end Gale conditions for the offshore
waters from the Central Coast to San Miguel Island by this
afternoon. 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. There
is a 30 percent chance tonight that enough of the channel will be
covered with these winds to warrant an SCA.

High confidence that winds will decrease each day Friday through
Saturday, but will increase again Sunday and Monday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory 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 PM PDT this afternoon
      for zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Saturday for
      zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB/jld
AVIATION...Kittell
MARINE...Kittell
SYNOPSIS...jld

weather.gov/losangeles

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