Fontana, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

393
FXUS66 KSGX 241057
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
357 AM PDT Tue Jun 24 2025

.SYNOPSIS...
A warming trend will begin today and continue through next weekend
with the greatest warming on Wednesday. High temperatures will
warm from 5 to 10 degrees below average for inland areas today, to
around 5 degrees above average for inland areas on Sunday. The
marine layer will become a little shallower for the latter half of
the week through the weekend with night and morning coastal low
clouds extending inland only into portions of the western valleys.

&&

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

.SHORT TERM (Today through Thursday)...
The marine layer is near 2500 to 3000 feet deep with satellite
imagery showing widespread low clouds over the coastal waters
extending well inland across much of the Inland Empire and
eventually across much of the San Diego County valleys.

Low pressure aloft across the southwest states will weaken with a
warming trend for today through the weekend. High temperatures
today will warm slightly at lower elevations to around 5 degrees
for the mountains with as much as another 4 to 8 degrees of
warming on Wednesday for the mountains, deserts, and inland
valleys and with another few degrees of warming on Thursday.

With the warming, high temperatures will go from 5 to 10 degrees
below average for inland areas today to around average for inland
areas on Thursday. With the warming, high temperatures on Thursday
will range from around 70 near the coast to the mid 80s to mid
90s for the Inland Empire with 104 to 108 for the lower deserts.

The marine layer depth will gradually decrease to around 2000 feet
by Thursday with night and morning coastal low clouds spreading
inland into only as far as the western valleys.

&&

.LONG TERM (Friday through Monday)...
A slow warming trend will continue through Sunday with Sunday high
temperatures around 5 degrees above average for inland areas,
ranging from the lower to mid 70s near the coast to upper 80s to
mid 90s for the Inland Empire with 108 to 112 for the lower
deserts. The marine layer will be near 1500 to 2000 feet deep with
night and morning coastal low clouds spreading inland into
portions of the western valleys.

&&

.AVIATION...
240900....Coast/Valleys...Low clouds have generally made it up to 20
miles inland for San Diego and Orange counties, with some patchy
spread into the Inland Empire. Bases 1600-2200ft MLS and tops to
2500-2800ft. Most of the IE should eventually fill in through 12z
with 50% chance of BKN CIGs reaching KSBD. -DZ and BR possible near
the coasts briefly between 11z-15z. Low clouds retreat to the coast
16-19z. Clearing will likely occur at the beaches by early
afternoon. Clouds redevelop after 01z Wednesday with similar or
slightly lower bases, pushing into coastal land areas after 03z.
Patchy clouds likely to reach into parts of the IE again by 10-12z
Wednesday.

.Mountains/Deserts...Clear skies and largely unrestricted VIS
through Wednesday morning.

&&

.MARINE...
No hazardous marine conditions are expected through Friday.

&&

.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...17
AVIATION/MARINE...Zuber