Chula Vista, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

176
FXUS66 KSGX 201523
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
823 AM PDT Sun Jul 20 2025

.SYNOPSIS...
Chances for mountain showers decrease for today. Temperatures
will remain mostly below average through this week. Marine layer
low clouds and fog will spread into portions of the inland valleys
each night and morning.

&&

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

.Morning Update...

Marine layer clouds will retreat to the coast by later this
morning with minimal clearing at the beaches into the afternoon.
Clouds will move back inland fairly quickly by the evening,
spreading into all areas west of the mountains overnight into
Monday morning. This morning`s sounding in San Diego reveals a
drier atmosphere as PWAT values are now below one inch. This,
along with a stronger mid level inversion, will only garner
minimal thunderstorm chances over the mountain crests this
afternoon. Hi-res models also show barely anything noticeable, so
a weak shower may occur if you`re lucky. Otherwise, the forecast
remains on track to see dry and cooler than normal weather through
the week.

.Previous Discussion (225 AM Sunday)...

The upper low over SoCal will gradually evolve into an open wave
through Monday as a low/trough over the Pacific Northwest deepens.
The sub-tropical high is displaced to the southeast over the Gulf
States. Extensive low pressure troughing will dominate the pattern
this week, continuing the drying trend as monsoonal moisture is
displaced to the east with the sub-tropical high. This will
continue to keep daytime high temperatures near or below seasonal
averages for all areas, including the lower deserts. It will also
maintain a persistent marine layer which will continue to bring
low clouds and patchy fog into the coastal areas and valleys each
night and morning. Model solutions remain in good agreement
through mid-week so forecast confidence is high for that period.
Solutions diverge somewhat as we approach next weekend so
confidence in forecast details is a little lower.


&&

.AVIATION...
201530Z....Coast/Valleys...Low clouds based 1400-1800 feet MSL will
continue to clear toward the coast this morning through 19Z, but
very little if any clearing is expected at the immediate coast. Low
clouds with similar bases will push inland after 23Z, filling the
coastal basin overnight. Scatter out Monday 17-20Z.

Mountains/Deserts...VFR conditions expected into Monday. SCT cumulus
based around 10000 feet will develop over the ridges 19-02Z. Slight
chance (10% probability) SHRA/TSRA over mtn ridges 21-00Z.

&&

.MARINE...
No hazardous marine weather is expected through Thursday.

&&

.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...APR/PG
AVIATION/MARINE...MM