Alhambra, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

834
FXUS66 KLOX 121747 AAA
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1047 AM PDT Sun Jul 12 2026

updated aviation discussion

.SYNOPSIS...12/906 AM.

Temperatures will increase each day into mid-week, resulting in
widespread Moderate to Major HeatRisk Tuesday through Thursday.
Monsoonal moisture moving into the area will add to the
discomfort, bringing shower and thunderstorm potential each day,
highest in the mountains.

&&

.SHORT TERM (TDY-TUE)...12/937 AM.

***UPDATE***

A hot and muggy week expected as an upper level high over the
northern plains tops out around 600dam, and is also favorably
placed to import tropical moisture from Mexico. PW`s peak tonight
and Monday around 1.5" and slowly fall the remainder of the week
but remaining as high as 1.35" Thursday. The best chance for any
precip reaching the ground remains today and Monday but can`t rule
out a few drops through mid week. And there also remains a 10-20%
chance of thunderstorms though that time, but the best chance of
those would be in the mountains.

The heat and humidity will be the biggest concern this week with
temperatures peaking on Wed. Extreme Heat Watches will almost
certainly become Warnings on Tuesday for most areas except
possibly along the immediate coast and continuing through
Thursday, though there is a 20-30% chance that warnings will
extend to the coast as well, especially the Santa Barbara South
coast where hot and strong Sundowners are expected to peak Tuesday
and Wednesday evenings, possibly bringing temperatures at the
beach into the 90s. Current projections indicate a 30-40% chance
of 110 degrees in the western San Fernando Valley on Wednesday and
a 60-80% chance of 95 or higher in Downtown Los Angeles.

***From Previous Discussion***

Satellite loops indicate a well-defined MCV centered near Yuma,
Arizona early this morning -- the remnants of diurnally enhanced
convection from yesterday that formed across southern Arizona and
adjacent northwest Mexico. In the past hour, convection has been
re-generating in the western semicircle of the MCV, reflective of
the focused ascent intercepting monsoonal moisture. It is
unlikely for the ongoing convection to persist into the local
area. However, these recent trends suggest that the MCV will
remain sufficiently in-tact as it pivots around the broader
western-CONUS anticyclone and eventually into portions of the
forecast area later today, to produce at least isolated sprinkles
across a broader portion of Los Angeles, Ventura, and Santa
Barbara Counties this afternoon. The forecast in these areas has
been updated to account for higher coverage of light-precipitation
mention this afternoon. The greatest chance for a few lightning
strikes will remain over interior sections of these counties,
though an isolated lightning strike cannot be completely ruled out
closer to the coast.

Aside from the potential for a few lightning strikes, significant
dry air in the lower troposphere and related sub-cloud
evaporation will minimize precipitation amounts, with little in
the way of wetting rains expected. However, ample sub-cloud
evaporation in the steep lapse-rate environment may also
accelerate downdrafts and boost the chance for locally gusty
winds with the afternoon round of midlevel convection. Local wind
gusts of 30-40 mph from variable directions will be possible.

Otherwise, increased cloud coverage associated with the
approaching MCV will tend to restrict the degree of diurnal
warming today. However, ample humidity -- characterized by lower
60s dewpoints across the Los Angeles basin -- amid the warm air
mass already in place will support the continuation of heat
headlines.

Ample mid and high level clouds are streaming into the region
from the south. Few (if any) observations sites have reported any
rain, thus most moisture is not reaching the surface and will
likely continue to fall mostly as virga through this morning.
Light showers are possible though, especially for San Luis
Obispo and Santa Barbara Counties. There remains around a 5%
chance of dry lighting through this morning. Today through Tuesday
there is a 10-20 percent chance of thunderstorms and showers over
the LA, Ventura, and far interior Santa Barbara County mountains,
while a 5-10 percent chance exists everywhere else. Storms are
expected to produce more measurable rain starting today, and
especially Monday and Tuesday. The influx of moisture will
increase the humidity, making conditions muggier and increase any
heat discomfort. The upper level clouds have disturbed the marine
layer clouds, which are patchy and have been scattering and
reforming overnight (the high clouds will also make for good
sunset conditions).

Through Tuesday, 500 mb heights will experience minimal changes,
but onshore flow will become much weaker. Some model guidance even
show weak offshore flow during the mornings staring on Tuesday.
This will dampen the cool seabreeze and allow for temperatures to
rise more each the day. A warming trend is anticipated for the
next several days, reaching widespread Moderate to Major HeatRisk
on Tuesday. This will pose a threat of heat related illnesses to
much of the population, not just those most vulnerable. All
headlines (Advisories and Watches) remain in effect with no recent
changes to the timings. Heat Advisories continuing into Tuesday
morning, then the Extreme Heat Watches are in place Tuesday
morning through Thursday evening.

Tuesday night, expect moderate Sundowner winds across southwest
Santa Barbara County, and increasing northwest winds across
interior areas.

.LONG TERM (WED-SAT)...12/319 AM.

Heat will be the primary hazard next week, and an Extreme Heat
Watch is in effect Tuesday through Thursday for all areas except
the beaches along the Central Coast. Widespread moderate to major
HeatRisk is anticipated for the region. Over the next couple
days, some locations are likely to to be converted to Heat
Advisories, while others may become Extreme Heat Warnings. High
temperatures in the warmest valleys and deserts have the potential
to be between 95 to 110 degrees. Even the beaches and coastal
plains may see highs between 85 and 95 degrees. Temperatures are
favored to trend down Friday into the weekend, though there is a
fairly large range of outcomes as to how much. The most likely
scenario would bring temperatures back down to near normal for
mid-July by the weekend. However, the humidity is poised to stay
through the extended period (and beyond), and this would still
present Minor to Moderate HeatRisk across much of the region,
especially away from the coasts. Ensembles suggest PWATs hover
around 1.5 inches during the period and even into the next week,
so muggy days are in the near and long term future here is
Southwest California.

The periphery of the high pressure centered over the Plains will
nose into the Southern California region starting Wednesday. This
will alter the flow pattern to be more southwesterly compared to
the southeasterly flow expected earlier in the week. This will
likely cut off the moisture source for the region, thus chances of
thunderstorms and showers will likely drop to around 10 percent
across the region for Wednesday and Thursday. However, starting
Friday, other influx of monsoonal moisture from the southeast will
be possible, and thunderstorm chances will likely bump back up to
around 20 percent. The thunderstorm forecast will be complex with
generally low confidence for any particular location, as storm
development will be highly dependent on mesoscale features and
even potential outflows form storms well outside of our forecast
area. The greatest chances will be during the afternoon and
evening hours across the mountains of Los Angeles and Ventura
Counties.

Moderate Sundowner winds for southwestern Santa Barbara County
and northwest winds over the interior are expected Wednesday
night and potentially Thursday night (although weaker Thursday).
Otherwise winds will trend slightly more onshore Thursday into the
weekend.

&&

.AVIATION...12/1742Z.

At 1721Z at KLAX, the marine layer depth was was 1700 ft. The top
of the inversion was at 3200 ft with a max temperature of 24 C.

High confidence in TAFs for KPMD, KWJF, KBUR, KVNY and KPRB.

Moderate confidence in the remaining TAFs. Mid and high clouds
will likely continue to disrupt the marine layer cloud formation
through tonight, and any cigs that do form are likely to be
patchy and scatter and reform frequently later tonight into Mon
morning.

KLAX...Moderate confidence in TAF. There is a 40% chance of no
MVFR cigs forming late tonight into Mon morning, and if any do
form they may bounce between BKN015 and BKN250. High confidence
that any east wind component will be below 6kt.

KBUR...Generally high confidence in TAF. There is a 10%-20%
chance of brief OVC008-015 cigs 12Z-16Z Mon.

&&

.MARINE...12/826 AM.

For the outer waters, winds and seas are largely expected to be
below Small Craft Advisory (SCA) levels through Tuesday, then
there is a 50%-60% chance of SCA winds and seas developing
Tuesday night through Thursday night.

For the nearshore waters along the Central Coast, mainly light
winds are expected through Tuesday, but winds will begin to
increase on Tuesday, likely reaching SCA levels Wednesday
afternoon through Thursday night. Short period seas may also reach
SCA levels.

For the inner waters south of Point Conception, conds are
expected to remain below SCA levels through the forecast period,
except for a 50% chance of SCA wind gusts over the western
portions of the Santa Barbara Channel Wednesday and Wednesday
night.

&&

.BEACHES...12/830 AM.

A south to southwest swell will continue to affect the coastal
waters through this week. With this longer period swell, the
potential for larger surf and a greater risk for rip currents will
continue.

Evening high tides are expected to increase this week with Monday
expected to be the highest tide of 7.1 to 7.7 ft above MLLW.
There is the potential for some minor coastal flooding this week
with the evening high tides and south swell. One thing that will
need to be watched late this week into the weekend will be the
potential of a greater south to southwest swell from potential
tropical cyclone over the eastern Pacific.

Thunderstorms will be possible along the beaches today into Monday
(10-20% chance). For more information, please refer to the Beach
Hazard Statement.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect until 10 AM PDT Tuesday for
      zones 38-88-343>345-353-368-372-373-375>380-548. (See LAXNPWLOX).
     Extreme Heat Watch in effect from Tuesday morning through
      Thursday evening for zones
      38-88-341>345-347>358-362-366>376-378>383-548. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Wednesday evening
      for zones 340-346-349-350-354-362-366. (See LAXCFWLOX).
PZ...NONE.

&&

$$

PUBLIC...MW/Cohen/Schoenfeld
AVIATION...Sirard
MARINE...Sirard
BEACHES...Sirard
SYNOPSIS...MW/Lewis

weather.gov/losangeles

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