139
FXUS66 KLOX 101146
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
446 AM PDT Mon Jun 10 2024

.SYNOPSIS...10/334 AM.

Temperatures will warm through Tuesday with a good clearing each
day. After a brief cooling trend Wednesday and Thursday,
widespread warmer temperatures are expected Friday through next
weekend with gusty northerly to northwesterly winds. Overnight to
morning drizzle will occur at times.

&&

.SHORT TERM (TDY-WED)...10/240 AM.

Today the base of an trough will separate and form a cutoff low.
This low will stall around 350 NM south of Point Conception
through Tuesday, and then start to slowly move northeastward
Wednesday. With the center of the low to the south, mild high
pressure will build over the region. The high pressure aloft and
decreasing onshore pressure gradients through Tuesday will drive
the temperature trends. Expect daytime highs to increase tomorrow
and peak on Tuesday, followed by a decrease on Wednesay. Interior
locations will largely be above normal, and highs will range from
the mid 80s up to around 103 degrees (across the Antelope Valley).
Coasts and valleys will be warmest either today to Tuesday, with
temperatures through the period in the upper 60s to low 70s at the
coasts, and upper 70s to mid 80s for valleys.

After good clearing for much of the region yesterday, stratus is
slow to redevelop south of Point Conception. The marine layer is
currently around 2000 ft deep and low clouds and fog are expected
to continue advancing across coasts and valleys before sunrise.
Even with onshore flow trending downwards through Tuesday, night
through morning low clouds and fog will persist in the short term.
However good clearing is expected each day, especially on today
and Tuesday. Drizzle will continue to be possible with marine
layer stratus, with the best chances on Wednesday night, when the
low pressure begins to move eastward. This upper level pattern
will cause lifting of the marine layer, which may result in enough
condensation to produce drizzle.

With lower onshore flow through Tuesday, southwesterly winds are
expected to lighten up somewhat over the Antelope Valley and
foothills. Wednesday, as gradients are expected to increases,
gusty winds are likely to return.

.LONG TERM (THU-SUN)...10/331 AM.

Thursday into Friday the low will track eastward across the area,
with the center expected to remain south of Los Angeles County.
This system lacks significant moisture and the highest amount of
vorticity will occur overnight, so afternoon showers/thunderstorms
over the mountains are unlikely. However, some low impact cumulus
clouds may develop Thursday afternoon over high terrain. There is
a good chance of drizzle Thursday morning when lowering heights
are likely to lift the marine layer. There will continue to be a
chance for drizzle Friday and Saturday when heights rise again,
compressing the marine layer.

Temperatures will keep trending downward for Thursday, because
onshore pressure gradients are expected to continue to increase
while upper level heights lower. Low clouds and fog will extend
far inland overnight and be slow to clear with strong onshore
flow. There is however a chance that the cold air aloft will
disturb the capping inversion above the marine layer, causing low
clouds to scatter out across the region.

Friday through the weekend will see a significant change in the
overall pattern. Dry NW flow will move into the area and hgts will
rise to 587 dam. Temperatures will trend upward through Saturday
with little change on Sunday. A strong NW to SE pressure gradient
will develop across the eastern Pacific and wind will increase
greatly. The winds appear strongest over the coastal waters and
the Santa Barbara South Coast, with a significant chance of
Sundowners Winds (and Gale Force winds for the waters). Northerly
pressure gradients will shift offshore Friday night (peaking
around 3 to 4 mbs), which will drive the north to northwesterly
winds at the surface. In conjunction, easterly onshore gradients
will weaken at this time. This trend will drive up daytime highs
by minimizing the influence of marine layer clouds/seabreezes and
increasing warm downslope winds (especially for the Santa Barbara
South Coast). For the weekend, expect in the 90s across the
interior and warmer valleys, 80s for the coastal valleys, and mid
to upper 70s at the coasts.

&&

.AVIATION...10/1145Z.

At 1105Z at KLAX, the marine layer was 2000 ft deep. The top of
the inversion was at 4900 ft with a temperature of 19 degrees C.

High confidence in KPMD and KWJF.

Good confidence in KPRB, KSMX AND KSBP where there is a 20
percent chc of VFR conds arriving an hour early or an hour late.

Low confidence in KVNY TAF with a near 50 percent chc of IFR cigs
13Z-17Z.

Moderate confidence in KSBA TAF with 30 percent chc of IFR cigs
13Z-19Z.

Moderate confidence in all other sites with VFR transition occur
+/- 1 hour of fcst time. Lower confidence again this evening with
regard to stratus arrival.

KLAX...Moderate confidence in TAF. There is a 30 percent chc of
clearing by 19Z. There is a 30 percent chc that onset of low
clouds Monday evening will be as late as 08Z. No significant
easterly wind component is expected.

KBUR...Moderate confidence in TAF. There is a 30 percent chc of
clearing by 17Z. Lower confidence in arrival of low clouds tonight
with near equal chances between 07Z and 11Z.

&&

.MARINE...10/332 AM.

For the Outer Waters, high confidence in current forecast. Low
end Small Craft Advisory (SCA) for the middle of the outer wasters
will very likely (80%) end this morning. High confidence in winds
and seas remaining below SCA levels through late Thursday. On
Friday, there is a 50-70% chance of both SCA level winds and seas.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. High confidence in winds and seas
remaining below SCA levels through late Thursday. On Friday,
there is a 40% chance of SCA level winds in the afternoon and
evening hours.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast with winds and seas remaining
below SCA levels through Friday.

The chance of gale force winds is increasing for next weekend and
will be monitored.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 9 AM PDT this morning
      for zone 673. (See LAXMWWLOX).

&&

$$

PUBLIC...Schoenfeld/Rorke
AVIATION...Rorke
MARINE...Rorke
SYNOPSIS...Hall/RS

weather.gov/losangeles

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