Stevenson Ranch, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

363
FXUS66 KLOX 151726
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
926 AM PST Mon Dec 15 2025

.SYNOPSIS...15/926 AM.

Well above normal temperatures will continue through Friday, with
locally gusty north to northeast winds peaking Tuesday Night and
Wednesday. Dry conditions will continue into next week, but the
potential for a winter storm continues to grow in the December 23
to 26 Christmas Holiday window.

&&

.SHORT TERM (TDY-WED)...15/923 AM.

***UPDATE***

The marine layer is currently around 800 feet deep, with low
clouds covering some coastal and valley areas for all counties
except Ventura County. Visibility under those clouds is quite low,
with most observation sites and webcams showing visibility under
1 mile. The trend over the last hour is towards improvement, so
expecting the current Dense Fog Advisory to be allowed to expire
on time at 10am. Locally breezy offshore flow will continue to
develop and expand today through Tuesday, which should greatly
shrink the fog at the same time, with really only coastal Los
Angeles County in line for any fog tomorrow. Forecast looks on
target with no immediate needs for changes.

***From Previous Discussion***

Marine layer clouds and isolated areas of radiation fog will give
way to partly cloudy skies today. The areas of dense fog have
prompted Dense Fog Advisories for the Santa Ynez and southern
Salinas valleys through later this morning.

Offshore winds from the north to northeast will trend stronger
today, but winds are expected to remain below advisory levels,
with strongest gusts in the 25-35 mph range across favored
mountains and valleys. Winds will begin to strengthen and turn
more northerly Tuesday and Wednesday, which will favor the I-5
Corridor as well as the Santa Ynez range. The best chance for
advisory level winds now appears to be Tuesday through Thursday,
but without a whole lot of upper level support, expecting winds to
remain sub advisory with some isolated gusts to 45 mph in favored
mountain and valley areas. The more significant part of the
offshore flow will be its effect on temperatures.

In addition to the increasing offshore flow ushering in warmer
temperatures via downsloping adiabatic warming, the persistent
upper level ridge of high pressure will rapidly build to around
588 dam at the 500 mb levels. This is quite strong compared to the
historical December average of 571 dam. Due to these factors, a
significant increase in high temperatures will result in coastal
and coastal valley areas jumping up 5 to 15 degrees compared to
yesterdays highs. Widespread highs in the 70s and 80s will be
common across the 4-county area. The only caveat to this is the
development of marine layer clouds across portions of coastal
Ventura County. In the low chance scenario that marine layer
clouds hang around through later in the morning, maximum
temperatures may be forecast too warm at the moment. Tuesday will
see a bump up in highs by a few more degrees as the offshore flow
and 500 mb heights increase, resulting in max temps 10-20 degrees
above normal for this time of year. Wednesday will feature a
cool down of a few degrees across much of the area, but
especially coasts and valleys as offshore flow from the east
weakens rapidly, potentially even flipping to onshore during the
day. While any low cloud development is uncertain, dense fog would
more than likely accompany it.

.LONG TERM (THU-SUN)...15/247 AM.

The warm and dry weather will continue, except for a low chance
for very light rain across northern San Luis Obispo County
Saturday night and Sunday. Offshore gradients from the north and
east strengthen early Thursday morning, then rapidly weaken and
turn onshore Friday. The upper level ridge will begin to flatten
out and break down, then southwest flow aloft will step in on the
heels of the seemingly endless and everlasting ridge. Marine layer
clouds will redevelop and return over the weekend.

Thursday features an increase in temps thanks to the offshore
flow restrengthening, then a gradual cool down brings SoCal and
the Central Coast back down to the 60s and 70s by Sunday.
Although a welcomed (to some) drop in high temps is upon us, max
temps will remain above normal for this time of year.

Ensembles continue to exhibit good agreement on widespread rain
coming to the region Christmas week. However, there still remains
a wide range of outcomes regarding both the timing and rain totals
with this system. Included in the uncertainty is potential for
significant rain. The Climate Prediction Center has stamped a
Moderate Risk for heavy precipitation from the Central Coast
south all the way to Imperial Beach from the 23rd through
Christmas Day. For those of you who have been wishing for rain,
you must be on Santas Nice List this year.

Next weeks stormy pattern does not appear to be a big snowmaker
for our area as the upper level trough will pull in moisture from
the southwest initially, then a plume from the south joins in on
the fun. Thus temperatures will remain too warm for any
significant snow.

&&

.AVIATION...15/1029Z.

At 1015Z at KLAX, the marine layer was 1000 feet deep. The top of
the inversion was at 3200 feet with a temperature of 19 degrees
Celsius.

For 12Z TAF package, high confidence in KBUR, KVNY, KPMD and KWJF.
For all coastal sites, and KPRB, moderate confidence in current
forecast as timing of flight category changes this morning could
be +/- 2 hours of current forecasts. For tonight, VFR conditions
are expected for all sites, except for a 20-30% chance of IFR/LIFR
conditions at KLAX and KLGB in the 08Z-17Z time frame.

KLAX...Overall, moderate confidence in 12Z TAF. Timing of
dissipation of CIG/VSBY restrictions this morning could be +/- 2
hours of current 18Z forecast. For tonight, there is a 20-30%
chance of IFR/LIFR conditions 08Z-17Z. No significant easterly
wind component is expected.

KBUR...High confidence in 12Z TAF.

&&

.MARINE...15/230 AM.

For the Outer Waters, moderate to high confidence in current
forecast. Today through Tuesday, high confidence in Small Craft
Advisory (SCA) level winds for all of the Outer Waters. For
Wednesday through Friday, high confidence in SCA level winds
continuing across PZZ673/676, but only a 30-40% chance of SCA
level winds across PZZ670. Seas will approach 10 feet in the
Wednesday through Friday time frame.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Today through Tuesday morning,
high confidence in winds and seas remaining below SCA levels. For
Monday afternoon through Wednesday, there is a 30-40% chance of
SCA level winds in the afternoon and evening hours. For Thursday
and Friday, high confidence in winds and seas remaining below SCA
levels.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For a majority of the southern
Inner Waters, high confidence in winds and seas remaining below
SCA levels. The only exception will be the western half of the
Santa Barbara Channel where there is a 30-50% chance of SCA level
winds in the Wednesday through Friday time frame, mainly in the
late afternoon and evening hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Dense Fog Advisory remains in effect until 10 AM PST this
      morning for zones 343-348. (See LAXNPWLOX).
     Dense Fog Advisory in effect until 10 AM PST this morning for
      zone 548. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 1 PM this afternoon to 9
      AM PST Tuesday for zones 670-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PST Tuesday for
      zone 673. (See LAXMWWLOX).

&&

$$

PUBLIC...Lewis/Kittell
AVIATION...RAT
MARINE...RAT
SYNOPSIS...RK

weather.gov/losangeles

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