484
FXUS66 KSGX 041645
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
845 AM PST Tue Nov 4 2025

.SYNOPSIS...
The marine layer will continue to deepen through tonight. This
will bring a slight chance of light showers for late tonight and
Wednesday morning for the coast and adjacent valleys. It will be
cooler on Wednesday and breezy in the mountains and deserts, then
dry and warmer for the Friday through the weekend. A low pressure
system developing well off the California coast early next week
could bring some precipitation by the middle or end of next week.

&&

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

.Morning Update...

The clearing pattern across Southern California via satellite
shows clouds quickly scattering out this morning, with another day
of mostly clear skies expected across the region today. Western
valleys will see high temperatures a few degrees cooler this
afternoon than yesterday with highs in the 70s and lower 80s. Hi-
res models show marine layer clouds filling much of the coastal
basin overnight with a chance of marine layer drizzle/light
showers closer to the coast by Wednesday morning. The forecast
remains on track for dry weather to continue into early next week
with the potential for wetter weather by later next week.

.Previous Discussion (332 AM Tuesday)...

.SHORT TERM (Today through Thursday)...

For tonight and Wednesday, a low pressure system moving inland to
the north will strengthen the onshore flow across southern
California and deepen the marine layer. Low clouds for late tonight
will spread into portions of the inland valleys with faster
clearing for San Diego County on Wednesday morning. The HREF shows
some light showers developing late tonight across the southern
California coastal waters, spreading locally inland near the coast
for Orange County northward. There will be stronger and gusty
southwest to west winds for the mountains and deserts for
Wednesday afternoon and evening with gusts to 25 to 35 mph along
and below the desert slopes of the mountains with gusts to around
45 mph in the northern Coachella Valley below the San Gorgonio
Pass.

High temperatures today will be slightly cooler, then as much as
4 to 8 degrees cooler on Wednesday for the valleys. High
temperatures on Wednesday will range from the mid to upper 60s
near the coast to the lower to mid 70s for the valleys with the
lower deserts in the mid to upper 80s. On Thursday, the coast and
valleys will begin to warm slightly while the mountains and
deserts continue to cool slightly.

&&

.LONG TERM (Friday through Monday)...
High pressure aloft will strengthen across California for the
weekend. The greatest warming is expected on Friday for the inland
valleys onto the lower coastal mountain slopes as the marine layer
becomes shallower. There will be slight additional warming during
the weekend. Sunday high temperatures will be mostly 5 to 10
degrees above average for inland areas, ranging from the lower to
mid 70s near the coast to the 80s for the Inland Empire with the
lower deserts around 90.

A low pressure system developing well off the California coast
early next week could bring some precipitation by the middle of
next week. NBM chances for measurable rainfall remain below 10
percent through Tuesday, then increase to around 20 percent on
Wednesday and 50 percent on Thursday. For Wednesday and Thursday
combined, NBM has around a 20 percent chance for one inch or more
of rainfall for Big Bear with snow levels falling from around
8500 feet on Thursday to 7500 feet on Friday.

&&

.AVIATION...
041630Z...Coasts/Valleys...Low clouds based at 800- 1200ft MSL
and VIS 0-5SM will continue for coastal and western valleys
through 17-18z. After, clouds clear back to the coast where they
may linger through the afternoon. Low clouds with higher bases
around 1200-1800ft MSL will push ashore 00-03Z, and spread into
most of the coastal basin overnight into Wednesday. VIS reductions
0-5SM for inland valleys and coastal mountain slopes.

Mountains/Deserts...Mostly clear and VFR conditions today and
tonight. Increasing high clouds AOA 20,000ft MSL late Wednesday
morning and Wednesday afternoon.

&&

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

&&

.BEACHES...
Long period (15-16 sec) west-northwest (290 degree) swell will
arrive Thursday, peak Thursday night, and gradually diminish Friday.
Surf of 4-6 feet is expected, locally higher on west-facing beaches.
This will present a high rip current risk.

&&

.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...17
AVIATION/MARINE...Zuber

NWS Tucson (SGX) Office