Avocado Heights, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

788
FXUS66 KLOX 161817
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1117 AM PDT Mon Sep 16 2024

.SYNOPSIS...16/919 AM.

Much cooler than normal temperatures will continue through the
next several days, before warmer conditions return for next
weekend. It will be windy at times today and tonight. There is a
small chance of rain or drizzle today and a better chance on
Wednesday. Areas of low clouds will be common over the coast and
coastal valleys, with areas of clearing each afternoon.

&&

.SHORT TERM (TDY-WED)...16/918 AM.

***UPDATE***

Trimmed back rain chances to be focused on the eastern San Gabriel
mountains this morning where a few light showers were observed on
radar. A few showers associated with a cold pool aloft may also
hold together long enough for brief light showers for northern San
Luis Obispo County through this afternoon.

A very deep moist layer between 6000-8000+ feet has enshrouded
our eastern mountains especially in LA County with clouds
providing welcomed moisture increases for active fires across
Southern California including the Bridge Fire. However, low end
advisory level winds continue across the ridge top and favored
canyons and slopes leading into the Antelope Valley. Advisory
level winds will also likely develop into the Oxnard Plain to
western Santa Monica mountains by this afternoon. Will expand the
current Wind Advisory to cover the Santa Monicas as a result. It
will also be breezy for most Ventura Valleys and southwest Santa
Barbara County, but likely (70-80 percent) below advisory levels.
Winds for most areas will drop off sometime this evening.

Low cloud forecast is challenging tonight as deep moisture in
place limits radiated cooling processes necessary to reform marine
layer clouds with the best shot for low clouds and patchy fog
across the Central Coast where a weak inversion has managed to
remain in place.

Focus today will be on our next system with another round of
increased marine influence, light drizzle, and breezy conditions
likely Wednesday and Thursday. We`ll also be looking at
thunderstorm potential with at least a very small chance (5%) of
activity over the Ventura and Santa Barbara interior mountains
Thursday afternoon.

***From Previous Discussion***

Today`s forecast is shaping up to be drier than previously
thought. A 556 dam upper low over Sacramento will bring cool
cyclonic flow to the area through the day. The marine layer has
responded to the lift associated with the flow by rising to 4000
or 4500 ft. Clouds almost too high to call stratus cover much of
the area including much of the lower elevation mtns. Due to the
depth of marine layer and the weak capping inversion expect to see
reverse clearing this afternoon with the coasts mostly clear but
the vlys covered with a BKN strata cu deck. It looks like the
layer of maximum humidity is thinner than fcst and also the
satellite shows the band of best PVA to already be east of the
area. These two things will really make it difficult to produce
rain or drizzle. The geography of the San Gabriel mtns and vly
will interact with the WSW flow and form one favorable area for
rain. Rain in this area is still likely, but have scaled back the
rain chances in other areas. Rainfall amounts could still reach a
quarter inch across the San Gabriel foothills but most other areas
that see rain will only see a trace or a couple hundredths.

The strong upper level WSW flow will interact with the moderate W
to E sfc flow to bring a 9 to 12 hour period of strong winds. The
winds will be strongest along the beaches, mtns and the Antelope
Vly Where wind advisories are in effect or will go into effect
later this morning. Look for 35 mph to 45 mph westerly gusts.

The real talking point for today`s weather will be the
temperatures as hgts fall to 569 dam. These low hgts will combine
with the strong afternoon onshore flow to lower max temps 2 to 4
degrees across the coasts, 3 to 6 degrees across the vlys, 5 to 10
degrees across the mtns and 10 to 15 degrees over the far
interior. Max temps today will almost all be in the mid 60s to
lower 70s or 10 to 20 degrees below normal.

NW flow will develop between today`s departing low and Wednesday
stronger low. Hgts will rise to 578 dam. There will only be
minimal low clouds in the morning as the marine inversion
struggles to reform. Max temps will rebound 3 to 6 degrees but
will still end up many degrees blo normal.

A second stronger upper low will move down into Srn CA on
Wednesday. Although this system does not carry that much more
moisture with it than today`s system, it is colder and more
unstable. By Wednesday afternoon the low will be over the Bay Area
with a 563 dam central hgt. Overnight it will move into SLO
county. A chance of rain will develop over SLO county Wed morning
and spread through SBA county in the afternoon. The chance of rain
will overspread the entire 4 county region Wednesday evening and
overnight. Its likely that most areas will see a period of rain or
two during this period but rainfall amounts will likely not exceed
a tenth of an inch and will probably register less than 5
 of an inch. Max temps will fall a few degrees (fortunately the
coldest portion of the storm will pass during the overnight hours)
and will remain 8 to 16 degrees blo normal.

.LONG TERM (THU-SUN)...16/323 AM.

The low will push to the east on Thursday morning. A chance of
rain will continue through the morning over VTA and esp LA
counties. Rainfall amounts if any will be light. There will be
clearing in the wake of the low and the afternoon should be sunny.
The winds behind he system do not look as strong and while the
afternoon winds will be stronger than normal they will likely not
reach advisory levels. Max temps will change little from
Wednesday`s cool readings.

Upper level ridging will build in Friday and persist through the
weekend. Hgts will rebound to 590 dam. The onshore flow will
weaken and may even turn slightly offshore in the early morning.
Skies will be mostly clear and any marine layer clouds will likely
be confined to western SBA county. Max temps will rise 4 to 8
degrees on Friday, 5 to 10 degrees on Sat and 1 or 2 additional
degrees on Sunday. Max temps will reach or slightly exceed normals
on Saturday and will mostly be 3 to 6 degrees over normal on
Sunday. For Sat and Sun look for 70s and lower 80s for the coastal
sections and 90s in the vlys.

&&

.AVIATION...16/1815Z.

At 1548Z at KLAX, there was a moist layer up to 5000 feet deep.
There was no inversion.

High confidence for TAFs at KPMD and KWJF.

Low confidence in all remaining TAFs. Sites south of point
conception will likely have cigs between 020 and 050 when cigs
return tonight thru tomorrow. There is a chance for LIFR
cigs/vsbys at KSMX (30%) and KSBP (10%) between 10Z and 16Z. There
is a 20% chance for IFR-MVFR cigs at KPRB from 10Z to 15Z. Minimum
flight cats may bounce frequently during the period at all sites.
Arrival time of cigs may be off +/- 5 hours from current
forecast.

KLAX...Low confidence in TAF. Cigs will likely vary between BKN020
and BKN040 thru 18Z tomorrow. Cigs expected by 07Z. There is a
40% chance that cigs could arrive as soon as 02Z. Cigs > BKN035
could arrive as early as 13Z. No significant east wind component
expected.

KBUR...Low confidence in TAF. Cigs will likely vary between
BKN020 and BKN040 through 17Z. Arrival and dissipation of cigs
may be off by +/- 4 hours from TAF.

&&

.MARINE...16/917 AM.

For the Outer Waters (Central Coast to San Nicolas Island),
moderate to high confidence in the forecast. For the northern zone
(Pt Piedras Blancas to Pt Sal) winds are likely to remain below
SCA level until Tues afternoon, then there is a 60-70% chance of
SCA level winds developing Tues afternoon thru Wed morning. From
Wed afternoon thru late Sun, moderate confidence in winds
remaining below SCA level, with a 30-50% chance of SCA winds Fri
thru Sun, with best chances Sun. For the southern zones (Pt Sal
to San Nicolas Island) moderate to high confidence in SCA level
winds persisting into early Wednesday, with a lull possible
Tuesday morning. There is a 40-60% chance of SCA winds continuing
thru late Wed. Moderate confidence in winds remaining below SCA
level Thurs, with lower confidence in the afternoon thru evening
Fri thru Sun.

For the Inner Waters off the Central Coast. High confidence winds
will remain sub advisory level thru Tues morning, then there is a
40-60% chance in SCA winds in the afternoon thru evening hours
Tues. Moderate confidence in winds being sub advisory Wed thru
Sunday, with lowest confidence in the afternoon thru evening hours
Fri thru Sun.

For the Santa Barbara Channel, high confidence in rapid
development in winds to Gale Force early this afternoon, then
rapidly decreasing thru late tonight. Winds are likely (50-70%
chance) to rapidly drop below SCA level on the heels of the Gale
Force winds. Steep, choppy seas and strong rip currents can be
expected thru late tonight. There is a 40-60% chance in SCA level
winds returning Tues and Wed afternoon thru late night, with
higher confidence Tues. From Wed to Sun, There is a 20-50% chance
of SCA level winds in the afternoon thru evening hours, with best
odds Fri and Sat.

For the nearshore waters off the Los Angeles and Orange County
coasts, SCA level winds will continue throughout much of the
zone. In the northwest portion of the zone from Malibu west to the
Channel Islands and as far south as Santa Barbara Island, winds
will rapidly increase to Gale Force by midday. Seas will be choppy
in this area, and exposed beaches may see strong rip currents.
Winds will quickly drop off to below SCA levels overnight into
early Tues. Moderate to high confidence in winds remaining below
SCA level Tues afternoon thru Sun.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 9 PM PDT this evening for zones
      354>357-369-374. (See LAXNPWLOX).
     Beach Hazards Statement in effect from 5 PM PDT this
      afternoon through late tonight for zones 354-362-366. (See LAXCFWLOX).
     Wind Advisory now in effect until 9 PM PDT this evening for
      zones 379-380-382. (See LAXNPWLOX).
     Wind Advisory remains in effect until 9 PM PDT this evening
      for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until noon PDT today for zones
      650-655. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Tuesday for zones
      650-655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Lewis
MARINE...Lewis/Phillips
SYNOPSIS...JB/RM

weather.gov/losangeles

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