LA Area Forecast Discussion

237
FXUS66 KLOX 272258
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
358 PM PDT Mon Oct 27 2025

.SYNOPSIS...27/909 AM.

The first Santa Ana Wind event of the season is expected Tuesday
and Wednesday, bringing very warm temperatures to the coasts and
valleys and gusty winds to the typically wind prone corridor of
Los Angeles and Ventura Counties as well as most mountains. Late
this week through the weekend, temperatures will remain above
normal with no rain chances in the foreseeable future.

&&

.SHORT TERM (TDY-THU)...27/240 PM.

The first Santa Ana Wind event of the season will start Tuesday
(tomorrow) and last through Wednesday, driven by offshore surface
pressure gradients that will set up across the region. A
relatively colder airmass has surged into the Central Valley,
resulting in a surface high to contrast the surface low pressure
along the SoCal Coast (the LAX-DAG and LAX- BFL gradients are
likely to peak around 5 mb offshore). This imbalance will drive
the offshore winds out the northeast over the next couple days.

Expect northeast winds to pick up tonight along the San Luis
Obispo County Santa Lucia Mountains and coastal areas (including
Morro Bay and Cayucos), then developing early Tuesday morning
across the Santa Ana wind prone corridor of Los Angeles and
Ventura Counties. Winds Advisories  are in effect the windiest
areas tonight through Tuesday, with additional advisories
possible for late Tuesday night into Wednesday morning (see NPWLOX
for more details).

The warm downsloping winds will lead to temperatures well above
normal temperatures across the region, including the coastal
plains and beaches. Heat Advisories are currently in effect
across much of Ventura and Los Angeles Counties Tuesday through
Wednesday, where daytime highs will be in the upper 80s to low
90s, which is 10 to 15 degrees above normal (see NPWLOX for more
details). Temperatures will approach daily records, especially
near the beaches.

Additionally, the influx of dry air from the interior will yield
very low relative humidities. Gusty winds and these dry
conditions will result in elevated to Critical Fire Weather
conditions, and Red Flag Warnings have been issued for the
Western San Gabriel Mountains, Santa Susana Mountains, and the
Southeastern Ventura County Valleys (see RFWLOX for more details).
Residents in or near theses areas are advised to check for
multiple ways to recieve weather and emergency alerts and make
preparations to evacuate in an emergency wildfire situation.

The Santa Ana winds will keep marine layer clouds at bay for the
next few days, with some low clouds and fog likely to return
Thursday morning. Heat will also let up somewhat on Thursday,
through temperatures will remain above normal with highs in the
80s common.

.LONG TERM (FRI-MON)...27/148 PM.

An extended period of broad ridging is favored to prevail over
the region Friday into early next week, with little variation
between forecast models. This will keep temperatures generally
above normal, though offshore surface pressure gradients are
expected to decrease, which will will allow for a cooling trend
for Friday. The ridge is likely to strengthening over the weekend,
resulting a minor bump in temperatures. At this point, heat
products are not likely to be needed. Additionally, there is
little indication of a pattern change in the foreseeable future,
with the next chance for rain well beyond the forecast period
(late next week in early November).

&&

.AVIATION...27/1816Z.

At 18Z at KLAX, the marine layer was 2000 ft deep. The top of the
inversion was 6000 ft with a temperature of 18 degrees Celsius.

High confidence in KWJF and KPMD TAFs.

Elsewhere, moderate confidence in VFR conditions by 20Z and
continuing through at least 04Z. Low confidence on low cloud
evolution after 04Z. LLWS will be a concern at KSBP tonight. NE
winds and/or LLWS will be a concern after 12Z Tuesday at KCMA KOXR
KVNY.

KLAX...Moderate confidence in VFR conditions 20Z-04Z. Low
confidence after, with a 50% chance of IFR conditions forming in
the 10-16Z window Tuesday. Moderate confidence that any easterly
wind component will stay under 08 knots.

KBUR...Moderate confidence in VFR conditions starting by 20Z and
likely lasting through Tuesday. NE winds will form over the region
on Tue. Moderate confidence that they will not surface at the
airport, but some weak-moderate LLWS may form.

&&

.MARINE...27/213 PM.

The current NW winds will shift to N-NE  through Tuesday. High
confidence in Small Craft Advisory (SCA) winds and seas through
tonight from the Central Coast (including nearshore) to San
Nicolas Island. 30% chance of reaching low-end Gales from Point
Conception to San Nicolas Island.

NE winds will impact the nearshore waters Tuesday and Wednesday
morning from Ventura through Santa Monica, as well as the
Central Coast. High confidence winds will peak at least in the 15
to 20 knot range. There is a 30% chance that winds cross over into
SCA criteria in terms of speed and duration.

NW winds will likely return to SCA levels from the Central Coast
to San Nicolas Island by Thursday.

Swells continue to be observed well above computer projections.

Patches of dense fog will likely form Thursday into Friday.

&&

.FIRE WEATHER...27/357 PM.

Gusty north winds combined with a drying trend will bring elevated fire weather
conditions through this evening across portions of the mountains, southern
Santa Barbara county, and Antelope Valley. Late tonight into Wednesday a weak
to moderate Santa Ana wind event will develop across southern California.
Northeast winds gusting 30 to 40 mph will be common on Tuesday across the
typical Santa Ana wind prone corridors of LA/Ventura counties, with isolated
gusts up to 45 mph across favored mountain/foothills areas. The offshore
winds are expected to diminish some in most areas Tuesday night into Wednesday
(with gusts mostly in the 20 to 35 mph range). However, high resolution models
indicating a secondary burst of wind gusts 35 to 45 mph late Tuesday night into
Wednesday morning across the western San Gabriels, Santa Susanas, and the
Highway 118 corridor of the eastern Ventura county Valleys (near Moorpark, Simi
Valley). This Santa Ana wind event will be associated with very warm and
dry conditions, especially across coastal/valley areas where downslope warming
will occur. Minimum humidities of 8 to 15 percent will be common across much
of LA/Ventura counties, falling to 5 to 10 percent on Wednesday. In addition,
there will be very poor humidity recoveries on Tuesday night with many wind
prone areas/foothills remaining in the 10 to 20 percent range.

The combination of gusty Santa Ana winds, very warm temperatures, and very
low humidities will bring widespread elevated to brief critical fire weather
conditions across the region Tuesday into Wednesday, especially wind corridors
of LA/Ventura counties where 2 to 5 hours of Red Flag conditions could occur
each day. The most enhanced wind areas on Tuesday and Wednesday (western San
Gabriel mountains, Santa Susanas, and southeast Ventura valleys mainly near
Simi Valley/Moorpark) will likely see 6+ hours of Red Flag durations,
resulting in the issuance of the Red Flag Warning for the longer duration
threat. Despite recent rains, local fire agencies indicating fuels are still supportive
of rapid fire spread and extreme fire behavior across portions of the forecast
area. Live Fuel Moisture values are still in the 65 to 75 percent range across
much of the area, with only a shallow grass crop forming in many areas
after recent rains. Residents in or near the Red Flag Warnings ares are
advised to check for multiple ways to recieve weather and emergency alerts
and make preparations to evacuate in an emergency wildfire situation.

Winds will continue to weaken on Thursday, but a light offshore wind influence
will continue to maintain very warm and dry conditions through the weekend
away from the coast.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 6 AM to 4 PM PDT Tuesday for
      zones 88-355-358-374-375-378-379. (See LAXNPWLOX).
     High Surf Advisory in effect until 9 AM PDT Tuesday for zones
      340-346. (See LAXCFWLOX).
     Wind Advisory now in effect until 11 AM PDT Tuesday for zones
      340>342-345. (See LAXNPWLOX).
     Heat Advisory remains in effect from 10 AM Tuesday to 7 PM
      PDT Wednesday for zones 354-355-358-362-366>375-548. (See LAXNPWLOX).
     Red Flag Warning in effect from 6 AM Tuesday to 6 PM PDT
      Wednesday for zones 374-375-379. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 11 AM PDT Tuesday for
      zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Schoenfeld
AVIATION...RK
MARINE...RK
FIRE...Gomberg
SYNOPSIS...RS

weather.gov/losangeles

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

NWS LOX Office Area Forecast Discussion