Descanso, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

612
FXUS66 KSGX 291017
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
317 AM PDT Thu May 29 2025

.SYNOPSIS...
A deep marine layer continues early this morning with coastal low
clouds extending will inland across much of the valleys along
with patchy drizzle for portions of the San Diego County coast and
valleys. Strengthening high pressure aloft over California will
bring much warmer weather for inland areas through Friday with
high temperatures today 5 to 10 degrees warmer than Wednesday and
another 5 to 10 degrees warmer on Friday with Friday high
temperatures as much as 10 to 15 degrees above average for the
Inland Empire. This will be followed by a cooling trend for
Saturday through Tuesday with Tuesday high temperatures as much as
10 to 15 degrees below average for the mountains. A closed upper
level low pressure system off the coast of northern and central
Baja will draw some tropical moisture northward into the area
during the weekend with the relatively greater chances for
showers over the mountains and on Sunday. A warming trend will
follow for the latter half of next week.

&&

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

.SHORT TERM (Today through Saturday)...
The late afternoon NKX sounding showed the marine layer was around
3500 feet deep with the saturated layer below the base of the
marine inversion around 2500 feet deep. There was patchy drizzle
for portions of the San Diego County valleys and the higher
coastal terrain on Wednesday evening with several reports of
light measurable amounts with patchy drizzle continuing
overnight.

High pressure aloft over California will bring 5 to 10 degrees of
warming for inland areas today with another 5 to 10 degrees of
warming for Friday. Friday high temperatures will be as much as 10
to 15 degrees above average for the Inland Empire with high
temperatures on Friday ranging from the lower to mid 70s near the
coast to the 90s to around 100 for the Inland Empire with 102 to
108 for the lower deserts. A cooling trend will begin on Saturday.

For the weekend, a closed upper level low pressure system off the
coast of northern and central Baja will draw some tropical
moisture northward into the area with precipitable water values
peaking on Sunday. There is a chance of showers over the weekend
with the relatively greater chances on Sunday and over the
mountains.

&&

.LONG TERM (Sunday through Wednesday)...
The cooling trend will continue through Tuesday with Tuesday high
temperatures as much as 10 to 15 degrees below average for the
mountains. Highs on Tuesday will range from the lower to mid 60s
near the coast to the lower to mid 70s for the Inland Empire with
the upper 80s to mid 90s for the lower deserts. This will be
followed by a warming trend for Wednesday through the end of next
weekend. A greater return of night and morning coastal low clouds
is expected for Sunday night into Monday morning with the low
clouds extending well inland and across much of the valleys. The
deeper marine layer will persist through Tuesday, then become
gradually shallower for the latter half of next week.


&&

.AVIATION...
290930Z...Coasts/Valleys...Low clouds based 1200-2000 feet MSL with
tops to 4000 feet will continue over the entire coastal basin into
foothills this morning. Reduced vis and obscurations between those
elevations. Patchy -DZ to produce lower cigs to 900 feet MSL and vis
3-5SM. Scatter out 17-20Z. Low clouds to push ashore after 03Z, but
only extend into western valleys overnight into Friday. Bases 800-
1400 feet MSL.

Otherwise...mostly clear skies and VFR conditions today and tonight.

&&

.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...17
AVIATION/MARINE...MM