Alhambra, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

463
FXUS66 KLOX 040609
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1109 PM PDT Sun May 3 2026

.SYNOPSIS...03/851 PM.

Cloudy and cool conditions will continue through Tuesday, with
increasing chances of mostly light rain. Warming and drying to
follow Wednesday through the next weekend, with high temperatures
approaching 90 degrees in some areas by Friday.

&&

.SHORT TERM (SUN-WED)...03/917 PM.

***UPDATE***

A very deep marine-like layer is bringing cloudy and cool
conditions from sea-level to 6,000 feet above. This is the result
of an onshore pressure gradient that almost reached 10 millibars
(topped out at +9.8) and low pressure aloft approaching the area.
With such a strong onshore wind pattern, we knocked on the door
of a Wind Advisory for the Antelope Valley and foothills today,
but stayed just under. Expect more of the same with those aspects
tomorrow.

A 560 decameter (at 500 millibars) low, currently centered 250
miles west of Santa Barbara, will slowly move to the east and into
Arizona by late Tuesday. This means that the core of the cold air
aloft associated with this low will pass right over the area,
which also means that the chances of showers will be on the rise
Monday into Tuesday. At this point, the highest chances are over
the mountains Monday afternoon and night, especially over the
Ventura County Mountains where rain is more likely than not. All
the classic convective parameters are fairly benign, but
experience shows that anytime a low`s core moves over the area,
thunderstorms are in play. The previously advertised chances of 5
to 10 percent still look very reasonable. While most showers will
be light, the added convective potential means that there will
likely be a shower or two or three that will bring brief moderate-
to-heavy rain over some undisclosed location. None of the models
have rates above 0.50 inches per hour, so the likelihood of one
of those heavy showers resulting in significant flooding is
really small, but some localized minor road flooding should be
planned for. With all of this stated, this low is not being forced
by the prevailing jet-stream (aka a cutoff low), so there is some
play in the timing, but the other aspects of this system are less
sensitive to the exact track and speed of the system.

***From Previous Discussion***

Clouds from a 4000 ft marine layer are struggling to clear this
afternoon, keeping temperatures mostly in the upper 50s to mid
60s at noon, 10-25 degrees below yesterday. Probably won`t see
too much more warming today except in the Antelope Valley where
highs will be in the 70s. Still a 5-10% chance for a shower or
brief thunderstorm in the mountains due to instability from the
upper low.

A slow moving upper low just off the coast will continue to create
a deep marine layer at least through Monday and likely into
Tuesday unless the inversion gets too weak, which is possible. In
any case, temperatures will remain well below normal with highs
mostly in the 60s. Brief periods of drizzle or light rain are
possible each of the next two days, though more likely across the
eastern San Gabriel Mountains and adjacent foothills and the
Central Coast. Lowest chances for rain will be from southeastern
Santa Barbara County through southwestern LA County where
downslope flow off the Transverse range will limit rain from
reaching the surface. Any amounts should remain below a quarter
inch, with many areas getting little to no rain.

Gusty west to northwest winds are expected following the system
Tuesday afternoon and evening, possibly requiring wind advisories
in some areas.

A warming trend will begin Wednesday and continue into next
weekend.

.LONG TERM (THU-SUN)...03/1252 PM.

Models continue to favor a return to summer-like weather later
next week and especially next weekend into the following week. A
strong ridge of high pressure start building over the eastern
Pacific Friday and move onshore will move over the region over
next weekend and likely peak early the following week (May
11-12). Models are also showing a little north to northeast
gradient during that time to provide an additional boost in temps.
By next Sunday and Monday there is a 40-50% chance of 90 degree
temps in Downtown LA and 100 degrees in the warmer valleys.

&&

.AVIATION...04/0607Z.

At 0523Z at KLAX, the marine layer was 5600 ft deep with an
inversion top at 6500 feet and a temp of 9 C.

Good confidence in TAFs with VFR cigs 040-060 through most of the
period and then improving further. There is a 20-30 percent chc
-SHRA along with a 5 percent chc of a -TSRA from 22Z-04Z.

KLAX...Fair confidence in TAF with only a 25 percent chc of BKN025
conds 08Z-16Z. There is a 20-30 percent chance of -SHRA 22Z-04Z.
High confidence that any east wind component with be AOB 6kts.

KBUR...Fair confidence in TAF with only a 25 percent chc of BKN025
conds 08Z-16Z. There is a 10-20 percent chance of -SHRA 22Z-04Z.

&&

.MARINE...03/922 PM.

For the nearshore waters inside the SoCal Bight, Small Craft
Advisory (SCA) west winds are likely (40-60% chance) Tuesday
afternoon and evening with a chance (30-40% chance) Wednesday and
Thursday nights, mainly in the channel.

For the outer waters, SCA NW winds are likely (40-60% chance) for
the waters near Point Conception to the northern Channel Islands,
possibly extending south to San Nicolas island. Winds will
increase again from the NW Wednesday night (for PZZ676) into
Thursday for the remaining outer zones through Thursday night.
Stronger winds will be possible Friday into the weekend.

Nearshore along the Central Coast there is a 30% chance for SCA NW
winds Tuesday and Wednesday nights, with a 30 to 40% chance of SCA
conds Thursday afternoon and night.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...MW/Kittell
AVIATION...Rorke
MARINE...Ciliberti
SYNOPSIS...RK

weather.gov/losangeles

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