Simi Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

419
FXUS66 KLOX 181548
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
848 AM PDT Wed Jun 18 2025

Updated Marine Section

.SYNOPSIS...18/221 AM.

Very warm conditions will continue today, trending back to around
normal by Friday and changing little into next week. June Gloom
low clouds will return to normal by Friday, with extra gloomy
conditions on tap for early next week. The moderate to strong
northwest winds from previous days will relax later today, but
reform Thursday night and peak Friday and Saturday.

&&

.SHORT TERM (TDY-FRI)...18/245 AM.

Another warm day on tap for today, as high pressure aloft peaks
and the already weak onshore flow persists. While coastal and
valley areas will see similar temperatures as yesterday, interior
valleys and mountains will bump up 3-8 degrees as highs of 95-105
become common (10-15 degrees above normal). While Heat Advisories
are not anticipated, there are pockets where the case could be
made (like the Santa Clarita Valley, Salinas Valley, and some
lower mountains like the Santa Monicas) as highs around 100
degrees are expected with lows around 70. As such, there will be
an elevated risk of heat illnesses for anyone active outdoors
during the heat of the day for those areas (much cooler conditions
are just a day or two away). The gusty northwest winds from the
last few days are finally weakening, and we will get a brief break
today. Some low clouds and likely dense fog are trying to form
along the Central Coast and the Los Angeles Coasts, but unsure how
much we will end up seeing.

A shortwave trough will slowly move through the area later
Thursday through Saturday. This will do a few things. First of
all, this will tighten the north-to-south pressure gradients while
descending some wind energy aloft closer to the surface. This
adds up to another round of moderate to locally strong northwest
to north winds. Expecting wind gusts of 30 to 50 mph to be common
over the typically wind prone areas, with a moderate risk of
isolated gusts to 60 mph over southern Santa Barbara County, the
I-5 Corridor, and the Antelope Valley. Winds this strong can cause
power outages and downed trees, as well as blowing dust in the
deserts. Secondly, this should help the marine layer to
reestablish itself, except for some of Ventura County and southern
Santa Barbara County thanks to the drying affect of the
aforementioned northwest winds. Lastly, the cooler airmass will
allow temperatures to trend down a little on Thursday, then much
more noticeably on Friday - with temperatures at or below normal
to follow through at least early next week.

.LONG TERM (SAT-TUE)...18/251 AM.

The moderate to locally strong northwest to north winds will
continue and peak in some areas Saturday Night, then gradually
weak Sunday into Monday. At the same time, heights aloft lower
further while onshore flow strengthens. South-to-north pressure
gradients also strengthen (with some projections showing LAX-BFL
at +6.0 millibars Monday and Tuesday) which is usually a good
indicator for poor afternoon clearing. As such, expect cool
conditions for the first half of next week with a few spits of
drizzle possible along the coast. Gusty onshore flow also looks
favorable for the typical interior spots.

&&

.AVIATION...18/1134Z.

At 0747Z at KLAX, the marine layer was 800 feet deep. The top of
the inversion was 3700 feet with a maximum temperature of 25 C.

Low to moderate confidence in TAFs for KSMX (30% chance of VFR
conditions through 17Z Wed), KLAX / KSMO / KSBP (10% chance of
BKN005-BKN015 cigs until 16Z Wed), and KLGB (20% chance of BKN008
cigs from 08Z-16Z). Timing of cig arrivals tonight may be off by
+/- 3 hours, and during peak gusty winds, speeds may be off by +/-
5 kts at times. High confidence in remaining TAFs.

KLAX...Moderate confidence in TAF due to uncertainty in marine
layer clouds. There is a 10% chance for BKN005-BKN015 cigs and/or
vsbys 3SM to 5SM until 16Z Wed. Low confidence after 06Z Thu for
cig height and arrival time. Any east wind component is expected
to be less than 6 knots.

KBUR...High confidence in TAF.

&&

.MARINE...18/847 AM.

High confidence in Small Craft Advisory (SCA) to Gale Force
northwest winds across the Outer Waters and Inner Waters along the
Central coast through the weekend. The period with the strongest
winds is likely to be Friday afternoon through Saturday night. For
the next several days seas will hover around 10 feet for the
outers waters, increasing to up to 14 feet late this week.

Across the Santa Barbara Channel, after a lull in the winds today,
a return of SCA level winds is likely Thursday through the
weekend. Gale force gusts are possible in the western portion of
the zone Thursday evening and again Friday and Saturday, with
winds potentially impacting immediate coastlines during this
period. Highest chance of significant winds impacting the
coastlines is Friday through Saturday in the afternoon through
late night hours.

For the Inner Waters off the Los Angeles and Orange County coasts
lower confidence in forecast for Thursday into the weekend as
winds could increase to SCA levels, but are favored to be confined
to the western portion of the zone away from the immediate
coasts.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 PM PDT Thursday for
      zones 645-673-676. (See LAXMWWLOX).
     Gale Watch in effect from Thursday afternoon through late
      Thursday night for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM to 6 PM PDT Thursday
      for zone 650. (See LAXMWWLOX).
     Gale Watch in effect Thursday evening for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zone 670. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Sunday for zone 670. (See LAXMWWLOX).
     Gale Warning in effect until 9 AM PDT this morning for zones
      673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM Thursday to 3 AM PDT Sunday
      for zones 673-676. (See LAXMWWLOX).

&&

$$

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

weather.gov/losangeles

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