Glendora, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

938
FXUS66 KLOX 101316
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
616 AM PDT Thu Apr 10 2025

.SYNOPSIS...10/433 AM.

High pressure over the region will continue a gradual warming
trend through Friday. Mostly sunny skies will prevail, except for
patchy night through morning low clouds and fog at the coast.
Daytime high temperatures will be well above normal away from the
coast through Friday, then a cooling trend will develop as onshore
flow returns for the weekend. Night through morning low clouds
will become a staple of the forecast over the weekend and into
early next week.

&&

.SHORT TERM (TDY-SAT)...10/433 AM.

An upper-level ridge of high pressure is in place over the West
this morning. Southwest flow aloft will keep onshore flow in
place albeit weaker than the past several days. A warming trend
will continue through at least today as the high amplifies over
the region. The latest model solutions and forecast ensembles
indicate 500 mb heights climbing and 950 mb temperatures warming
over the area. One to three degrees of warming is forecast for
most areas today, most pronounced away from the coast.

Onshore flow will keep a shallow marine intrusion in place today
and keep the air mass from getting excessively hot. Any low
clouds and fog that develop will likely form dense fog.
Currently, low clouds and fog are patchy at best with the most
organized cloud field extending into the Long Beach Harbor area
and into the Santa Ynez River Valley early this morning. The
latest surface observations indicate visibilities near dense fog
criteria but still above.

A tough call with temperatures for Friday across the Southland as
the latest deterministic solutions indicating lowering 500 mb
heights and cooling 950 mb temperatures. While a cooling trend is
expected to get underway for areas north of Point Conception and
the Central Coast, the temperatures will be tricky for daytime
temperatures south of Point Conception. The forecast continues a
warming trend, despite 500 mb height means and 850 mb temperatures
falling. The latest deterministic solutions bring down 500 mb
heights and cool 950 and 850 mb temperatures as the ridge axis
pushes to the east. Although 1000-500 mb thickness values climb in
the latest deterministic model solutions, all other parameters
and the overall synoptic pattern would suggest a cooling trend
developing. Increasing southwest flow aloft some bring an increase
in onshore flow. The latest forecast keeps Friday as the warmest
day, but it does back down some from the amount of the warming
that was advertised previously. Future shifts will need to
address this discontinuity as even the latest forecast guidance
advertises an cooling trend taking shape.

A cooling trend will definitely establish by Saturday. A large
area of stratus moving down the Central Coast this morning alludes
to things to come. Onshore flow will strengthen and a persistent
marine layer with expanding low clouds and fog will move into the
region over the weekend. The marine layer will deepen each night
and morning through the weekend and into early next week. If NAM
BUFR time height sections play out as advertised, the marine layer
depth should deepen to 1000 feet deep by Sunday morning. There is
a low chance that marine layer depth could deepen to 1500 feet by
Sunday morning. A cooling trend with night through morning low
clouds will spread into the valleys through the weekend.
Temperatures for Saturday cool significantly but will still be
above normal for this time of year.

.LONG TERM (SUN-WED)...10/427 AM.

A cool week is setting up for next week as several troughs aloft
move over the region. The low pressure systems will likely be cut
off as the upper-level flow pattern splits. A cooling trend with
a deepening marine intrusion is forecast and that seems to be the
forecast. As each trough moves over the region, there is a chance
of low clouds and fog reaching the coastal slopes of the
mountains and a chance of night through morning drizzle or light
showers.

&&

.AVIATION...10/1315Z.

At 12Z at KLAX, the marine layer was about 400 feet deep. The top
of the inversion was near 2000 ft with a temp of 21C.

Low clouds and fog were affecting southern portions of the L.A.
County Coast, with patchy low clouds on the Central Coast and in
the Santa Ynez Valley. Conds were mostly LIFR to VLIFR. Cigs
should dissipate by mid morning, then VFR conds are expected thru
this evening. Areas of low clouds and fog with IFR-LIFR conds are
expected late tonight on the L.A. County Coast, and possibly the
VTU County Coast and the southern portions of the Central Coast.

KLAX...Fairly high confidence in the 12Z TAF. There is a 10-20%
chance of IFR cigs from 15Z-17Z this morning. There is a 20%
chance that IFR to LIFR cigs tonight may arrive as early as 08Z.
Any east wind component should remain below 7 kt thru the pd.

KBUR...High confidence in the 12Z TAF with VFR conds thru the pd.

&&

.MARINE...10/607 AM.

In the outer waters, Small Craft Advisory (SCA) level winds
will develop across this morning, except this afternoon in the
southern zone (PZZ676), then will persist thru Sun. SCA level
seas, which will develop Fri or Fri night will likely linger
into Sun evening. 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 30% chance of
gales in the southern zone during that same time period.

In the nearshore waters N of Pt Conception, SCA winds are likely
(80% chance) during the afternoon/eve hours thru Sat. SCA level
seas may linger thru late Sat night. There is a 20% chance of
gale force winds during the afternoon/eve hours Fri and Sat.

In the Santa Barbara Channel, there is a 30% chance of SCA level
winds across western portions this afternoon/eve, then SCA level
winds are likely (80% chance) across western portions during the
afternoon/eve hours Fri and Sat, with a 30% chance of SCA winds
pushing into eastern portions.

In the southern inner waters, there is a 30% chance of SCA level
winds from Anacapa Island to Malibu in the afternoon/eve hours
Fri and Sat. Otherwise, SCA conds are not expected thru Sun night.

&&

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

&&

$$

PUBLIC...Hall
AVIATION...DB
MARINE...DB
SYNOPSIS...Hall

weather.gov/losangeles

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