356
FXUS66 KLOX 250918
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
218 AM PDT Sun Oct 25 2026

.SYNOPSIS...25/215 AM.

Dry and warm conditions will continue through the first half of
this week. Cooler conditions will follow, with a growing
potential for a storm system towards the end of the week and into
next weekend.

&&

.SHORT TERM (TDY-TUE)...25/216 AM.

Overall, latest models in good synoptic agreement through the
short term period. At upper levels, weak ridge will move across
the area tonight/Sunday with broad cyclonic flow developing on
Monday and Tuesday. At the surface, a general weak diurnal flow
will prevail through Monday with weak onshore flow on Tuesday.

Forecast-wise, relatively benign weather is expected through the
short term period. With the gradual return of onshore pressure
gradients, the marine layer should start to become more
established from night-to-night across the coastal plain.
Otherwise, skies are expected to remain mostly clear through the
period.

With respect to winds, the weakening of the offshore flow the last
couple of days will keep any offshore winds rather weak and
localized tonight through Monday. On Tuesday, more widespread
onshore winds will return to the area, but speeds will remain well
below advisory levels.

Finally as for temperatures, there will be minor day-to-day
changes through Monday, mainly at the whims of the onshore flow
and marine influence. On Tuesday, will expect some slight cooling
for most areas with the uptick in onshore flow.

.LONG TERM (WED-SAT)...25/216 AM.

For the extended, latest models continue to exhibit a rather broad
synoptic agreement, but differ in the details. At upper levels, a
low will develop over the Pacific Northwest on Wednesday/Thursday.
On Friday and Saturday, the GFS continues to drop the low south
along the coast while the ECMWF keeps over the Pacific Northwest
(resulting in a sharp trough sweeping across the area).

Overall, either solution indicates a wet and unsettled Halloween
weekend for Southern California. At this time, there is high
confidence in measurable rainfall for most, if not all, of the
area Friday through the weekend. However, confidence in timing of
rainfall and totals remain very low. The latest 12Z/18Z runs have
backed off on totals just a bit with even the run total QPF on the
ensembles decreasing. Previous estimates of totals from 0.50 to
2.00 inches are still in play, but totals, in the end, could be
more or less than that range.

The uncertainty in this pattern will be a challenge over the
coming days. So, the forecast will likely change from one day to
the next. However, residents should expect Halloween activities to
be impacted by rainfall to some level. Stay tuned for the latest
details about this upcoming storm.

&&

.AVIATION...25/0917Z.

At 09Z over KLAX, there was no marine layer and no inversion.

High confidence in VFR conditions at all TAF sites through at
least Sunday, except a 20% chance of LIFR FG near KSMX 12-16Z.
Chances for LIFR/IFR ceilings Monday 10-16Z at KPRB 30%, KSBP 20%,
KSMX 40%, KLAX 20%, KLGB 20%.

KLAX...High confidence in VFR conditions, except for a 20% of
LIFR/IFR conditions Monday 12-16Z. High confidence in any east
winds staying under 08 knots.

KBUR...High confidence in VFR conditions through at least Monday
with typical winds.

&&

.MARINE...25/214 AM.

High confidence in fairly benign conditions through early Monday.
Small Craft Advisory (SCA) winds likely to form over most waters
Monday afternoon, including the nearshore waters. SCA winds will
retreat to the typical outer waters for Tuesday and Wednesday.

Dense fog is likely to form over portions of the coastal waters
over the next 48 hours, but low confidence on exactly when and
where.

A significant storm system will impact the area sometime in the
late Thursday through early next week timeframe. There is a
wide range of outcomes, but there is at least a low threat of a
12-24 hour period of strong winds and step seas.

&&

.BEACHES...25/216 AM.

Very high tides between 7.5 and 8.0 feet (roughly 1.0-1.5 feet
above astronomical predictions) are expected during the morning
hours of Sunday through Thursday over all coastal areas, with the
highest towards Los Angeles County. Monday through Wednesday could
produce the highest on record (current record at San Pedro is 7.93
feet set on Jan 10, 2005 with records going back to 1924).

Minor coastal flooding is likely purely based on the high tides.
While these tides might be the highest of all-time, similar
extreme tides in the past tell us that coastal communities should
expect shallow flooding of harbor walkways, beach parking lots and
bike paths. With swells and surf on the lower-end during these
extreme tides (2-3 feet), the threat of more significance/damaging
impacts should be limited to the most vulnerable areas that have
little-to-no sandy beach left and have already seen water damage.

With that said, these is a small change for more elevated surf on
south-facing shores around Wednesday as waves from a southern
Hemisphere storm arrive. The majority of computer projections keep
this wave energy on the small side, but a couple are a little
larger.

With all of these considerations in play, Coastal Flood
Advisories are in effect Sunday through Thursday. There is a low
potential for targeted Coastal Flooding Warnings if a larger swell
develops and produces elevated surf on top of the very high
tides.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory in effect until 1 PM PDT Thursday for
      zones 340-346-349-350-354-362-366. (See LAXCFWLOX).
PZ...NONE.

&&

$$

PUBLIC...Thompson
AVIATION...RK
MARINE...RK
BEACHES...RK
SYNOPSIS...Ciliberti

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office