Crystalaire, California Weather Forecast Discussion

121
FXUS66 KLOX 140606
AFDLOX
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1106 PM PDT Sat Sep 13 2025
UPDATED AVIATION SECTION
.SYNOPSIS...13/828 PM.
A warming trend will continue with temperatures increasing a
couple degrees each day through Thursday next week. Night through
morning low clouds and fog will cover many coasts and coastal
valleys through at least Tuesday, and some of the fog could become
dense. The heat will peak during the middle of next week, and
will be replaced by a slow cooling trend as well as chances for
showers and thunderstorms starting Wednesday and lasting through
the following weekend.
&&
.SHORT TERM (SAT-TUE)...13/842 PM.
***UPDATE***
High temperatures today ranged in the 60s to 70s across the
beaches, 70s to 80s across the valleys, and up to the low 90s
across some of the interior locations such as the Antelope Valley.
Current satellite imagery shows splotches of clouds across the
coasts, and honestly looks randomly placed. Current forecast leans
towards the clouds filling in more, expanding across the Central
Coast, as well as into the Oxnard Plains, across the LA coast and
possible into the Coastal Valleys including San Fernando. However,
with how fast the clouds are clearing out from the coastal
waters, the Central Coast may struggle to see widespread clouds
overnight. Sunday will continue to have benign weather and high
temperatures will increase across the region by 2-5 degrees,
locally up to 10 across the interior and near the foothills.
Besides slight adjustment to the sky coverage for tonight,
forecast looks to be in shape and no other changes were needed to
the evening update.
***From Previous Discussion***
No significant weather issues expected through Tuesday. A weak
trough will move through Oregon later tonight and Sunday but that
will have little to no impact this far south. The marine layer was
still around 3000 feet this morning south of Pt Conception and it
should still be somewhere between 2000 and 3000 feet tonight as
well so expecting most coast and valley areas to fill in with
stratus overnight. Some lowering of the marine layer is expected
along the Central Coast tonight and Sunday morning as the trough
passage. In addition, a light northeast flow is expected to
develop that should lead to several degrees of warming there,
especially along the coast due to the downsloping effects there.
Heights will start rising following the trough passage Monday and
Tuesday. This is expected to bring down the marine layer depth
and lead to warming for areas south of Pt Conception. By Tuesday
some of the warmer valleys are expected to reach low end triple
digits while inland coastal areas will be in the 80s to around 90.
One possible caveat for Tuesday is that the 12z NAM was much more
aggressive with the return of monsoon flow and was hinting at an
earlier start to the convection with CAPE values over 1000J/kg,
mainly over the coastal waters. This could be a potential dry
lightning risk since the deeper monsoon moisture will still be
south of the area. While a few of the ensemble solutions showed
showers as early as Tuesday across our area, most were were still
favoring Wed or Thu as the more likely start to possible
convection locally.
.LONG TERM (WED-SAT)...13/218 PM.
Still looking like a potentially active monsoon pattern for the
middle and end of next week. Ensembles have been very consistent
with increasing PW`s next week, peaking on Thursday between 1.5
and 2" across LA County and as high as an inch across the Central
Coast. The threat of thunderstorms will cover the entire forecast
area and not just the mountains and deserts. Showers and storms
could develop at any time of day or night given the ample moisture
and instability. There will be a risk of flash flooding,
particularly in the mountains and deserts, but even lower
elevations will be at risk for brief periods of heavy rain.
At the same time the air mass will be warming up and with
increasing humidity the concern will be for increasing heat risk
factors across region-wide. Confidence remains rather low right
now due to the uncertainty of the cloud and possible rain/storm
coverage. The most likely days for heat hazards would probably be
Tue and Wed before the deeper moisture and higher rain/storm
chances arrive.
&&
.AVIATION...14/0605Z.
At 0514Z at KLAX, the marine layer was 1700 ft deep. The top of
the inversion was at 3200 ft with a temperature of 22 C.
High confidence in KPMD and KWJF TAFs.
Low to moderate confidence in all coastal and valley TAFs due to
patchy nature of clouds, especially for sites south of Point
Conception. Timing of CIG/VSBY restrictions may be off by 2
hours & flight categories may be off by one cat at times when CIGs
are present. Cigs may also bounce between SCT and BKN through at
least 18Z. There is a chc for no low clouds at KPRB (30%), KBUR
(15%), and KVNY (15%).
KLAX...Moderate confidence in TAF. Cigs may SCT and reform at
times, especially through 10Z. Clearing times may be off +/- 2
hours, and arrival times may be off +/- 3 hours. There is a 40%
chance cigs remain OVC010 and higher once cigs arrive after 00Z
Mon. No significant east wind component expected tonight. 20%
chance of an east wind reaching 8 kts 10Z-17Z Mon.
KBUR...Moderate confidence in TAF. Arrival and clearing times may
be off by +/- 2 hours. 30% chance cigs remain over BKN010. However,
there is a 10% chance for no low clouds tonight.
&&
.MARINE...13/913 PM.
Small Craft Advisory (SCA) level NW winds (20-30 kts) will impact
the outer waters and the nearshore waters along the Central Coast
through late Sunday night, peaking in the afternoon and evening
hours, with relative lulls each morning. There is a 50% chance of
Gale Force winds (34-38 kts) Sunday afternoon and evening over
the northern Outer Waters beyond 20 NM from shore. The chance of
Gales nearshore to 20 NM away from shore is 20%. Seas are
expected to diminish some early this coming week, before building
to 6 to 8 feet Thursday into Friday. Conditions are expected to
stay below advisory levels on Monday and Tuesday.
For the inner waters south of Point Conception, conditions are
generally expected to remain sub-advisory thru at least Tuesday.
Local SCA level wind gusts cannot be ruled out.
An upper-level low will draw sub-tropical moisture northward
across the coastal waters mid-week, bringing chances of showers
and thunderstorms to the area.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 PM PDT Sunday for zone
      670. (See LAXMWWLOX).
     Gale Watch in effect from Sunday afternoon through late
      Sunday night for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Monday for
      zones 673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...MW/KL
AVIATION...Lewis
MARINE...Ciliberti
SYNOPSIS...MW/KL
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

NWS LOX Office Area Forecast Discussion