Ontario, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

602
FXUS66 KSGX 261724
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1024 AM PDT Thu Mar 26 2026

.SYNOPSIS...
Record setting heat will continue for some inland areas into the
weekend. Mid and high clouds will spread across the area during the
weekend. A low pressure system moving inland through California
around the middle of next week will spread cooling inland for Monday
through Wednesday of next week with inland high temperatures falling
to a few to around 5 degrees below average on Wednesday. There is a
slight chance of precipitation for Tuesday into Wednesday of next
week.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

...NEW AVIATION...

.SHORT TERM (Today through Saturday)...
The marine layer is slightly shallower than 24 hours ago, around
1500 feet deep, with satellite imagery showing coastal low clouds
spreading into the western valleys in San Diego County and spreading
northwestward across the coast and coastal plain in Orange County.
The coastal low clouds could eventually spread  into far southern
and western portions of the Inland Empire around sunrise this
morning. The marine layer will become gradually shallower into
Saturday with coastal low clouds only spreading into the far western
valleys for early Friday and mostly not past coastal areas for early
Saturday.

There will be slow warming into Saturday with high temperatures for
some inland areas as much as 20 to 25 degrees above average on
Saturday. High temperatures on Saturday will range from the 70s near
the coast to the lower to mid 90s for the Inland Empire with the
lower deserts in the upper 90s. Mid and high clouds from the
southwest will spread across the area on Saturday.

&&

.LONG TERM (Sunday through Wednesday)...
Weak onshore flow will return on Sunday and strengthen next week as
a low pressure system moves toward the California coast and inland
through California around the middle of next week. Cooling will
begin to spread inland on Sunday with greater cooling for Monday
through Wednesday of next week. High temperatures on Wednesday of
next week will be mostly in the mid 60s to lower 70s for the coast
and valleys and in the upper 70s to mid 80s for the lower deserts, a
few to around 5 degrees below average for some inland areas.

That low pressure system will also bring a chance of showers for
Tuesday into Wednesday with any rainfall ranging from less than one-
tenth inch near the coast to one-tenth to locally one-quarter inch
along the coastal slopes of the mountains. There remains model
spread on both the time and potential amounts. Cluster analysis
shows the model ensemble solutions with the greater potential to
generate at least some light precipitation around Tuesday night and
Wednesday of next week are those that are slightly stronger with the
low pressure centered along the California coast.

&&

.AVIATION...
261720Z...Low clouds have cleared the coast with some minor vis
restrictions lingering at KONT. Low clouds will return along the
coast this evening after 02Z-03Z Friday and gradually increase in
coverage (07Z-09Z) with bases 300-800ft MSL. Reduced vis 0-5SM will
be possible in fog on higher coastal terrain and western valleys.
Vis restrictions expected 4-6SM for coastal TAF sites. Conditions
will improve after 16Z-19Z Friday.

Otherwise, mostly clear skies and VFR conditions will prevail.

&&

.MARINE...No hazardous marine conditions expected through Tuesday.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...Martin
AVIATION/MARINE...Villafane