Duarte Weather

437
FXUS66 KLOX 181209
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
509 AM PDT Sun Oct 18 2026

.SYNOPSIS...18/209 AM.

A significant cool down is expected across southwest California
through the middle part of the week. Widespread rain is likely
Wednesday and Thursday with a slight chance of thunderstorms.

&&

.SHORT TERM (TDY-TUE)...18/212 AM.

Today will kick off a 4-5 day stretch of cooling. It will still be
quite warm today with pockets of moderate heat risk (NO heat
products needed) with widespread highs in the 80s to near 90. The
heat will be just a memory by Tuesday with seasonal temperatures
in the 70s.

One last morning of decent offshore mountain to canyon winds are
anticipated before onshore trends support prevailing afternoon to
evening onshore winds with light winds at night by Tuesday as
pressure gradients slowly turn onshore.

There is a 20-50 percent chance of night to morning low clouds
and fog returning by Monday morning, highest along the Central
Coast with more widespread coverage likely by Tuesday morning. Mid
to high clouds may be on the increase late Tuesday, a harbinger
of our upcoming storm.

.LONG TERM (WED-SAT)...18/452 AM.

Above normal confidence in widespread rain at times Wednesday into
Thursday in particular (yes is a bit delayed from earlier
thinking). Despite fairly good agreement among guidance,
confidence in forecast details remain below normal due guidance
historically performing poorly with cut-off closed lows such as
this system. Two scenarios remain very much in play.

Scenario 1 (60-70 percent chance): Cold low pressure that passes
through the region. This scenario is more dynamic with increased
potential for bands of moderate to heavy rain with rainfall totals
0.5-1.5 inches except local 1-3 inches southwest facing mountain
slopes and foothills. Los Angeles, Ventura, and southern Santa
Barbara County may be on the higher end of these ranges. There is
about a 20 percent chance of thunderstorms in this scenario. Flood
and debris flow concerns would be enhanced, especially near
recent burn scars.

Scenario 2 (20-30 percent chance): The system slows and peaks in
intensity far offshore and weakens considerably while moving over
southern California or tracks to our south. Rain chances more
sporadic and less guaranteed with this scenario with around 0.25
inches of rain (0.5-1 inch in the mountains). The lower totals
are related to less near storm dynamics and low pressure to our
south inducing weak offshore flow. Historically this type of
pattern has cut into rainfall totals, especially near the coast.
The risk for thunderstorms or flooding would be MUCH diminished.

Both scenarios would be chilly, especially compared to our
current weather pattern with highs only in the 60s and 70s.

By Friday and Saturday, the upper low will have moved eastward.
In its wake, weak to moderate offshore flow is likely. So, expect
dry and locally breezy conditions along with a warming trend.

Our (CPC) week two (Oct 25-31) outlook favors above normal rain
and near normal temperatures. So we may be heading into a pattern
supportive of additional rain towards the end of the month.

&&

.AVIATION...18/1208Z.

At 08Z at KLAX, there was a weak surface inversion to 600 feet,
with a temperature of 27 degrees C.

High confidence in VFR TAFs through 06Z, with wind gusts rapidly
decreasing this afternoon into the evening hours. After 06Z there
is a 20-40 percent chance of IFR or lower cigs/vsbys at coastal
terminals, except 60 percent for KSMX.

KLAX...High confidence in VFR TAF through 06Z with a 20 percent
chance of IFR or lower cigs/vsbys 06-16Z. East wind component of
3-6 kts will likely weaken or reverse to onshore 15-17Z. There is
a 10 percent chance of 8 kts east wind component for an hour or
longer through 16Z.

KBUR...High confidence in TAF.

&&

.MARINE...18/227 AM.

Conditions will remain relatively benign this morning, but SCA NW
winds will increase this afternoon through late tonight over the
outer waters (increasing first in the northern section, with
stronger winds pushing southward over the outer waters through
around midnight. The SCA winds will persist through Tuesday
evening or late Tuesday night. SCA winds may return to portions of
the waters Thursday evening. Finally, there is a 40% chance of
SCA winds in the western Santa Barbara Channel Monday night (as
well as Thursday night).

A moderate- strength storm system is becoming more likely in the
Tuesday through Thursday timeframe with a 10-20 percent chance of
thunderstorms.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect from 9 AM PDT this morning
      through Tuesday morning for zones 354-362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT Monday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 9 PM this evening to 3 AM
      PDT Tuesday for zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect from midnight tonight to 3 AM
      PDT Tuesday for zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Munroe
AVIATION...Munroe
MARINE...Ciliberti/RM
SYNOPSIS...RM

weather.gov/losangeles

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

NWS LOX Office Area Forecast Discussion