Stevenson Ranch, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

454
FXUS66 KLOX 111132
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
432 AM PDT Fri Apr 11 2025

.SYNOPSIS...11/323 AM.

Another warm day is on tap for today with temperatures above
seasonal normals, then a cooling trend will establish over the
weekend and into early next week as onshore flow strengthens.
Night through morning low clouds will become a staple of the
forecast over the weekend, pushing into the valleys by early next
week and into coastal slopes by mid week.

&&

.SHORT TERM (TDY-SUN)...11/432 AM.

Another warm day is in the forecast today, but a cooling trend
will establish. Most of the cooling will take place for the
Central Coast, but a slight tick down in temperatures will occur
today for most areas. While a degree or two of cooling will be on
tap for the Southland, daytime temperatures will still well above
seasonal normals for today. Onshore flow will strengthen this
afternoon and bring more significant cooling on Saturday. A
cooler air mass will likely be in place through the weekend.

Low clouds and fog continue to kept at bay this morning, but some
low clouds are creeping northward along the South Coast of
California. Patchy low clouds and fog could fill in later this
morning across the Southland coastal areas as an eddy is progged
to form shortly after sunrise this morning. To the north, a fresh
stratus deck is pushing down the Central Coast of California and
low clouds and fog should start to spread into the Central Coast
beaches as the morning progresses. Patches of low clouds and fog
cannot be entirely ruled out again for the Santa Ynez River valley
this morning. The forecast leans more heavily on night through
morning low clouds and fog over the weekend as NAM BUFR time
height sections indicate a more pronounced marine influence due
to much stronger onshore flow. The marine layer induced low clouds
should become more expansive and extensive through the weekend,
with some beaches possibly struggling to clear on Sunday.

Outside of the marine layer and across the interior, temperatures
will likely remain above normal into early next week. Increasing
high cloudiness will make for a partly cloudy day and evening
across the area today, but periods of high clouds will stream over
the area as broad troughing become entrenched along the West
Coast over the weekend.

.LONG TERM (MON-THU)...11/429 AM.

A much cooler week is looking to shape up for next week as a
split flow pattern develop. A series of cutoff troughs of low
pressure will move over the region. Due to the uncertainty of the
movement of the troughs in the split flow pattern, there is large
spread of solutions across the medium range ensemble members, but
confidence is higher for cooler temperatures than the last several
days. Climatology favors cut off troughs affecting southern
California this time of year, and these troughs will likely make
for a tough time for forecasting the smaller details of the
pattern. While the first of the series should affect the region
early in the week, the forecast leans toward cooler temperatures
and a deep marine layer, but night through morning drizzle or
mountain showers cannot be ruled out in the pattern. A few
ensemble members have precipitation developing between Monday and
Tuesday, but pattern recognition of the deterministic solutions of
the GFS would introduce the possibility of mountain showers and
maybe isolated thunderstorms over the mountains during the
afternoon and evening.

As we get into the latter part of next week, cluster analysis
favor another cutoff trough moving over the southern California
region, potentially a stronger trough that could bring a chance of
showers to the region. A cooler air mass should be expected with a
mix of clouds and sun. Both GEFS and EPS ensemble members bring
the lowest 500 mb height means for the latter portion of next
week, which should equate to much cooler temperatures and trend
toward an unstable air mass. GFS solutions currently indicate a
559-561 dam trough moving over the Southland for latter half of
next week, climatologically strong enough to produce rain for
KLAX. Forecast values go with NBM solutions for now.

&&

.AVIATION...11/0006Z.

At 2330Z at KLAX, the marine layer was around 400 feet deep. The
top of the inversion was near 2200 ft with a temp of 24 C.

Moderate confidence in coastal TAFs with a 25 percent chc of no
cigs at sites with cigs and a 20 percent chc of LIFR cigs 11Z-17Z
at sites with no cigs fcst.

High confidence in inland TAFs.

KLAX...Moderate confidence in TAF 09Z-17Z with a 25 percent chc of
no low clouds. High confidence for the rest of the times. Good
confidence that any east wind component will be under 6 kt.

KBUR...High confidence in TAF.

&&

.MARINE...10/809 PM.

In the outer waters, A GALE WARNING is in effect for the northern
zone (PZZ670) through late tonight for wind gusts up to 35 kts.
Otherwise, Small Craft Advisory (SCA) level winds (21+ kts) are
expected (>90% chance) to persist thru at least late Sat night or
early Sun morning across the outer waters. SCA level seas (10+
feet) will develop Fri afternoon/eve and will likely linger into
Sun afternoon. There is a 50-60% chance of GALE force winds in the
northern two zones (PZZ670/673) Fri afternoon thru Sat evening,
so a GALE WATCH has been issued. There is a 40-50% chance of GALES
in western portions of PZZ676 during aforementioned timeframe.
Will let the overnight shift assess whether or not an upgrade to
GALE warning is necessary.

In the nearshore waters N of Pt Conception, a combination of SCA
winds and seas are likely (>80% chance) thru late Sat, especially
in the afternoon and evening hours. SCA level seas could linger
thru late Sat night. There is a 30-40% chance of GALE force winds
during the afternoon/eve hours Fri and Sat.

In the Santa Barbara Channel, SCA level winds are likely (50-70%
chance) across western portions during the afternoon/eve hours Fri
and Sat, with a 20% chance of SCA winds pushing into eastern
portions.

In the southern inner waters, there is a 10-20% chance of SCA
level wind gusts during the afternoon/eve hours on Fri and Sat
around Anacapa Island. Otherwise, SCA conds are not expected thru
Sun.

Sub advisory conds expected Sun afternoon through Tues across the
entire coastal waters.

&&

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

&&

$$

PUBLIC...Hall/Ciliberti/Rorke
AVIATION...Rorke
MARINE...Black/Lewis
SYNOPSIS...Hall

weather.gov/losangeles

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