Rancho Santa Margarita, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

285
FXUS66 KSGX 270401
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
901 PM PDT Thu Jun 26 2025

.SYNOPSIS...
For the coast and valleys, slow warming will continue into Saturday
followed by slow cooling into Tuesday. For the deserts, slow warming
will continue into Tuesday. Highs on the warmest days will be around
5 degrees above normal. The marine layer will mostly fluctuate
between 1500 and 2000 feet deep with night and morning coastal low
clouds spreading into the western valleys late each night.

&&

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

Satellite imagery at 9 PM was showing low clouds becoming more
widespread along the Southern California coast. The inversion on the
00Z KNKX sounding was around 1500 ft deep. Low cloud coverage is
expected to expand eastward from the immediate coast into the
western valleys overnight. High temperatures Friday are expected to
be 2 to 4 degrees warmer than today. Forecast remains on track.

From previous discussion issued at 2 PM June 26...

Upper level high pressure will gradually build in from the southeast
through Saturday, continuing the warming trend for all areas. By
Saturday, high temperatures will be near to about 5 degrees above
normal across the region. The marine layer will become more shallow,
with low clouds becoming confined to the coastal areas and western
valleys each night and morning. Ensembles are showing some increase
in mid-level moisture Saturday afternoon and Sunday as the upper
high becomes centered near the Four Corners, but at this time it
only looks like enough for some cumulus development over the
mountains each afternoon.

A weak upper level low pressure system off the California coast on
Saturday will move slowly eastward to a position along the
California coast on Tuesday. This will bring slight cooling to the
coast and valleys for Sunday through Tuesday while the deserts
continue to slowly warm through Monday with not much change for
Tuesday. For Tuesday, high temperatures will range from the lower
70s near the coast to the mid 80s to mid 90s for the Inland Empire
with 108 to 112 for the lower deserts.

&&

.AVIATION...
260315....Coast/Valleys...A shield of low clouds based 1000-1500 ft
MSL sits over the waters awaiting nightfall to begin its march
inland...Coastal areas will mostly fill in by 06z. Valleys will
slowly fill in thereafter, up to about 15 miles inland. May reach
the western/southern IE after 10z with a 60% chance of BKN CIGs
reaching KONT. VIS reductions 2-5SM for western inland valleys,
western IE and higher coastal terrain, especially after 09z as CIGs
may lower slightly overnight. Clearing to the coast 15-18z. 40-50%
chance for BKN CIGs all day at the beaches and over waters. Low
clouds based 800-1300 ft MSL slowly move into coastal areas after
03z Saturday bringing VIS restrictions over elevated coastal terrain.

.Mountains/Deserts...Clear skies with unrestricted VIS through
Friday evening.

&&

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

&&

.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...CO/SS
AVIATION/MARINE...KW