Spring Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

473
FXUS66 KSGX 080510
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
910 PM PST Sun Dec 7 2025

.SYNOPSIS...
Warm and dry conditions with periods of Santa Ana winds expected
this week. The peak of the heat is expected to be mid-week. Patchy
low clouds could develop overnight into Monday morning near the
coast.

&&

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

.Evening Update...

A few areas of low clouds and fog continue to drift over parts of
the coastal waters this evening. Very isolated spots of fog may
occur near the coast through the early morning, but most areas
are expected to stay clear overnight.

Though the weekend has ended, the warm weather has not! The
forecast remains on track to see high temperatures 10 to 20
degrees above normal for the upcoming week. Tuesday will be the
warmest day for valleys west of the mountains with chances near
20% to 60% to see highs at or above 85 degrees. The ridge has a
good chance to break down some by next weekend, leading to a slow
cooling trend.

.Previous Discussion (141 PM Sunday)...

For tonight into Monday morning there is a 10 to 20 percent
chance of patchy low clouds and dense fog developing along the
coast, with slightly higher chances of dense fog developing over
the coastal waters. Mostly clear skies will prevail from Monday
afternoon through the middle of the week due to periods of weak to
moderate Santa Ana winds.

A persistent surface high pressure over the Great Basin will remain
in place through Saturday. This will bring weak to locally moderate
Santa Ana winds to the area. With no upper level support, the
strongest winds will remain confined to coastal mountain slopes,
foothills, and below passes. The strongest winds are expected on
Tuesday with gusts 25 to 45 mph. A secondary peak in winds is
expected on Friday. The airmass getting pushed into Southern
California from the Great Basin will be on the drier side, with
minimum afternoon relative humidity for inland areas falling to 10
to 20% each afternoon through Friday, bringing periods of elevated
fire weather conditions.

An upper level ridge over the East Pacific will strengthen over the
US West Coast through Tuesday, bringing an uptick in high
temperatures. High temperatures on Tuesday will be 15 to 20 degrees
above average. Widespread highs in the low to mid 80s are forecast
across the inland coastal areas into the valleys as well as the low
deserts. Weaker Santa Ana winds and a weakening in the upper level
ridge will allow for minor cooling on Wednesday and Thursday mainly
for coastal areas. The secondary uptick in Santa Ana winds on Friday
is expected to bring additional warming to areas west of the
mountains with high temperatures expected to run up to 20 degrees
above average for inland areas. Nights and mornings will remain
cool, especially in the wind-sheltered areas, minimizing any heat
impacts. A few degrees of cooling is expected into next weekend as
weak onshore flow returns, but temperatures will continue to run
above average.

&&

.AVIATION...
072100Z...Clear skies and VFR prevail region-wide through Monday.
10-20% chance for very patchy fog/vis reductions developing
within 5 miles of the coast overnight. Offshore E/NE winds
gusting 25-35 kts to pick up through mountain passes and Santa Ana
mountain coastal slopes after 13z Mon, clearing out any leftover
fog near the coast.

&&

.MARINE...
Patchy dense fog this evening will continue to be isolated through
early Monday morning. Visibility in fog 1 nautical mile or less.

&&

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


&&

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

&&

$$

UPDATE...APR
PUBLIC...CO
AVIATION/MARINE...APR