813
FXUS66 KSGX 022026
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
126 PM PDT Thu Oct 2 2025

.SYNOPSIS...
Cooler conditions with an uptick in winds in the mountains and
deserts Friday. In addition, the marine layer will deepen with low
clouds expected to spread into portions of the inland valleys for
tonight and Friday night. Slightly warmer Saturday west of the
mountains with weak offshore flow. Cooler conditions expected Sunday
and Monday with warming next Tuesday through Thursday.

&&

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

A trough of low pressure is expected to move into California on
Friday and east into Nevada on Saturday. This will bring 3 to 7
degrees of cooling to inland areas on Friday, with an increase in
winds for the mountains and deserts. Winds will peak in strength
Friday afternoon and evening. Wind gusts 35 to 50 mph expected
overall, with the potential for gusts up to 55 mph in portions of
the San Diego deserts and up to 60 mph through the San Gorgonio
Pass. Additionally, with the increase in onshore flow the marine
layer is expected to deepen. Areas of low clouds are expected to
reach into the valleys for tonight into Friday morning.

As the upper level low moves over Nevada Saturday, the overall flow
will quickly switch to offshore early Saturday morning. The
north/northeasterly winds associated with the offshore flow are
expected to be fairly weak and localized to the San Bernardino and
Santa Ana coastal mountain slopes. While the marine layer will still
be fairly deep, any low clouds that develop Friday night into
Saturday are expected to clear fairly quickly in the Inland Empire
and Orange County. Highs on Saturday are expected to be a few
degrees warmer than Friday west of the mountains, likely due to the
weak offshore flow. Temperatures in the deserts will continue to
cool a few degrees into Saturday.

A broad trough of low pressure will set up over the western United
States on Sunday. This will result in a few degrees of cooling west
of the mountains, with additional cooling expected into Monday for
most locations. For next Tuesday and Wednesday, the pattern becomes
a little more uncertain with ensemble guidance struggling to pin
down the amplitude and position of the aforementioned trough. The
solutions with a deeper trough over California would continue the
cooler conditions while the solutions with the trough to our east
with weak ridging over California would bring slightly warmer
conditions. Current forecast follows the NBM which leans towards the
warmer solutions for next Tuesday through Thursday.

&&

.AVIATION...
022015Z....Coasts/Valleys...Low clouds will redevelop after 03Z for
the coastal areas initially, and then begin to fill in from west to
east, mainly after 08Z for the inland areas tonight into Friday
morning. Bases should be around 1500 feet MSL, rising over 2000 feet
MSL early Friday, filling much of the coastal basin. They will begin
to scatter out beginning around 16-17Z for the inland areas, and
then eroding away from east to west to the coastal areas by around
18-19Z Saturday. Some of the CIGs over the inner waters could invade
portions of the San Diego County, and Orange County coastline during
the afternoon tomorrow. Clouds will continue to fill back in and
become overcast along the coast beginning around 01-03Z Saturday,
then filling back in from west to east, with slightly lower bases.

Mountains/Deserts...Mostly clear and VFR conditions tonight and
tomorrow.

&&

.MARINE...
Northwest winds Friday afternoon and evening over the outer waters
near San Clemente Island will likely lead to hazardous conditions
for small craft, as winds are expected to periodically exceed 25
kts. Otherwise, no hazardous marine conditions are expected through
Monday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 4 PM Friday to 5 AM PDT Saturday for San
     Diego County Deserts.

     Wind Advisory from 6 AM Friday to 5 AM PDT Saturday for San
     Gorgonio Pass near Banning.

PZ...Small Craft Advisory from 11 AM to 11 PM PDT Friday for Waters
     from San Mateo Point to the Mexican Border Extending 10 to
     60 nm out including San Clemente Island.


&&

$$

PUBLIC...CO
AVIATION/MARINE...Stewey