Spring Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

168
FXUS66 KSGX 051629
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
929 AM PDT Thu Jun 5 2025

.SYNOPSIS...
There is a slight chance of showers and thunderstorms for this
afternoon for the San Bernardino Mountains and the High Desert. The
marine layer will stay a similar depth into Friday with patchy
drizzle overnight and Friday morning. A gradual warming trend is
expected through the weekend, with the potential for continued
warming into early next week.

&&

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

Visible satellite at 9 AM was showing low clouds from the beaches to
the coastal mountain slopes, locally through passes. Areas of
drizzle had been observed overnight and early this morning. Low
clouds will clear inland areas through the morning but may linger
along portions of the coast most of the day. The marine layer is
expected to be a similar depth tonight into Friday morning, with
areas of drizzle likely. The marine layer is expected to get
shallower over the weekend as higher pressure tries to build from
the south.

The 12Z NKX sounding still showed 1.02 inches of precipitable water.
That is still enough moisture to keep slight (15-20 percent) chances
of showers and thunderstorms this afternoon for the San Bernardino
mountains and High Desert. HREF is indicating rainfall rates
are unlikely to exceed 0.30 inches per hour. The atmosphere
continues to dry out Friday through the weekend, with no
additional chances of showers/thunderstorms through the forecast
period.

Conditions will warm into the weekend with the potential for warming
to continue into early next week. There remains spread in the
guidance in whether a weak low pressure system off the California
coast will move into southern California for early next week or
instead weaken and move to the west with high pressure to the south
expanding into southern California. How this plays out will have an
impact on at least our high temperatures and cloud coverage. The
scenario with the weak low pressure system moving into southern
California would bring a deeper marine layer with cooling for the
coast and valleys. The scenario with high pressure expanding
northward into the area would bring warmer conditions with a
shallower marine layer. NBM chances for high temperatures to exceed
110 degrees in the low deserts are the highest on Monday at 15 to 20
percent. Chances for high temperatures to exceed 105 degrees are
highest Sunday and Monday at around 95 percent. West of the
mountains, chances of exceeding 100 degrees for Monday and Tuesday
are localized to the eastern Inland Empire at 10 to 20 percent.
Chances of exceeding 95 degrees are 5 to 15 percent for the valleys,
with local areas in the eastern portion of the Inland Empire closer
to 40 percent on Monday and Tuesday.

&&

.AVIATION...
051530Z....Coast/Valleys...Low clouds based 1800-2200ft MSL and -DZ
have successfully pushed inland, encompassing most areas except the
foothills and higher terrain. VIS down to 1-3SM for anywhere that
clouds intersect terrain and down to 4-6SM for areas of -DZ. Slow
clearing occurs today from E to W after 18z, with higher confidence
of clearing for Orange County and far northern San Diego County
clearing by 21z. Some areas, especially southwestern SD County may
not see full clearing today (50% confidence in no clearing). Low
clouds push inland again after 00Z with very similar coverage,
bases, vis, and patchy -DZ overnight into Friday morning, with
similar slow clearing late Friday morning.

Mountains/Deserts...Mostly clear today and tonight. Cumulus and ISO
SHRA/TSRA based at 10,000ft MSL 18-01Z over mountains and high
desert.

&&

.MARINE...
No hazardous marine conditions are expected today 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
AVIATION/MARINE...Zuber