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FXUS66 KLOX 041133
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
433 AM PDT Sat Oct 4 2025

UPDATED AVIATION SECTION

.SYNOPSIS...03/621 PM.

An upper-level trough of low pressure will continue to exit the
region through Saturday. Skies will continue to clear with gusty
northerly winds expected in portions of Santa Barbara, Ventura,
and Los Angeles Counties into early Saturday. Cooler than normal
conditions will linger into late next week as broad troughing
remains over the West. A warming trend is possible for late next
week.

&&

.SHORT TERM (TDY-MON)...04/232 AM.

Overall, 00Z models in good synoptic agreement through the short
term period. At upper levels, low will continue to move across
the Great Basin today then another low develops off the Central
California coast Sunday/Monday. Near the surface, weak diurnal
flow prevails today/Sunday then onshore flow strengthens on
Monday.

Forecast-wise, no significant issues are expected in the short
term. Northerly winds from last evening across the Santa Ynez
Range and I-5 Corridor have begun to diminish as flow will turn
weakly northeasterly this morning. Given current trends, will let
the WIND ADVISORIES expire at 500 AM this morning for these areas.
For the balance of today and Sunday, weak diurnal flow will
prevail with only isolated locations flirting with advisory level
offshore winds. So, no additional advisories are anticipated. By
Monday, weak onshore flow will prevail throughout the day.

As for sky conditions, low clouds will be very limited this
morning, confined to the Central Coast as well as interior
sections of the area (due to the weak northeasterly flow). For
tonight/Sunday morning, HREF indicates bit more widespread
stratus/fog across the Central Coast as well as the LA county
coast. With the onshore flow returning on Sunday night and
lowering H5 heights, inversion will deepen and stratus/fog should
be much more widespread and push into the Santa Clarita Valley by
Monday morning. Other than this stratus/fog, skies are expected to
remain mostly clear through Monday.

As for temperatures, expect 4-8 degrees of warming for most areas
today. For Sunday, there may be an additional degree or two of
warming. By Monday, the increased marine influence will bring some
cooling to the coastal plain, but little change across the valley
and interior sections.

.LONG TERM (TUE-FRI)...04/233 AM.

For the extended, 00Z models start out in decent agreement, but
gradually deviate later on in the period. So, confidence in the
forecast details drops off noticeably by Thursday/Friday.

For Tuesday/Wednesday, both the GFS and ECMWF weaken the upper low
off the Central Coast and move it inland. With this pattern, no
significant issues are expected. Marine layer stratus/fog will
continue across the coasts and valleys, but should diminish in
areal coverage from night-to-night. As for temperatures, areas
west of the mountains will remain rather persistent, but interior
sections will exhibit some slight warming.

For Thursday/Friday, the potential for much more interesting
weather remains along with a much lower confidence in the forecast
details. Essentially, a potent upper level low is forecast to
develop somewhere offshore from the Pacific Northwest/Northern
California while likely tropical storm Priscilla move up off the
Baja Mexico coast. The operational ECMWF seems to be the odd model
out, bringing Priscilla up to around Bahia Tortuga by Friday,
while most other guidance (GFS, ensemble means of GFS/ECMWF and
even the ECWMF AI) move Priscilla out to sea west of Cabo San
Lucas. Either way, there will be some increase in PWATs as
moisture from Priscilla is advected northward across the area. So,
there will be a threat of some convective precipitation for the
area Thursday/Friday, based on a decent number of various model
ensemble members. So, current forecast has slight chances for all
areas during the Thursday-Friday time frame which is good for now,
given the uncertainty in how the pattern develops.

&&

.AVIATION...04/1129Z.

At 1042Z at KLAX, the marine layer was 800 ft deep, with a weak
inversion up to around 1100 ft with a maximum temperature of 17
C.

High confidence in VFR TAFs for KSMX, KSBP, KSBA, KOXR, KCMA,
KPMD, and KWJF.

Moderate confidence in remaining TAFs. 10-30% chance of MVFR cigs
developing between through 17Z for remaining LA County sites
outside of KLGB as cigs are present there, highest chances at KLAX
and KSMO. A disorganized marine layer may lead to very brief cigs
and frequent transitions between SCT and BKN. At KSBA, north winds
may be very erratic and gusty through 15Z. Winds will likely
abruptly diminish.

KLAX...Moderate confidence in TAF. There is a 30% chance of
BKN010-BKN018 cigs through 17Z. Through 17Z, there is a 40%
chance of an east wind component reaching 8 kts.

KBUR...Moderate confidence in TAF. There is a 15% chance of
BKN010-BKN025 cigs from 13Z-17Z.

&&

.MARINE...04/140 AM.

High confidence in Small Craft Advisory (SCA) level winds across
the outer waters and nearshore waters along the Central Coast
through early Sunday morning, with lulls nearshore through this
afternoon. Localized Gale Force wind gusts may occur in the
southwestern outer waters through early this morning. Seas will
be between 8 to 11 feet through this morning before decreasing.
Then conditions are likely to remain sub advisory through mid-
week.

High confidence in winds decreasing through this morning this
morning across the Southern California Bight, although localized
Gale Force winds may occur along the southwestern Santa Barbara
County coastline as northerly Sundowner winds have made their way
downslope the Santa Ynez range all the way to the coast. Seas
will remain steep and choppy through this morning, especially
beyond 5 NM from shore. SCA level winds will fill the Santa
Barbara Channel again this afternoon and evening and seas will be
choppy. The waters adjacent to Los Angeles and Orange counties
will calm down through this morning. Thereafter, conditions
generally look to remain below SCA criteria through mid-week.

Hazardous boating conditions will linger into later today, but
confidence is high in improving conditions relative to Friday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zones 645-650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Sunday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Sunday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Thompson
AVIATION...Lewis
MARINE...Lewis
SYNOPSIS...Hall

weather.gov/losangeles

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