310
FXUS66 KSGX 040313
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
813 PM PDT Fri Oct 3 2025

.SYNOPSIS...
Gusty winds expected over the mountains and deserts, peaking this
afternoon and overnight. Cooler conditions today, with weak offshore
winds and warming west of the mountains Saturday. Another brief cool
down for early next week, with a gradual warming possible into the
middle/end of next week.

&&

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

This evening update...This afternoons`s 00z sounding shows several
weak inversions below 6000 feet MSL with the most significant
inversion above 8000 feet MSL. This evening, patchy clouds have
developed along inland foothills and over mountain ridges,
characteristic of a sweeping trough through the region. Clouds in
the marine layer have been slightly convective as a result,
yielding once again the chance for spotty drizzle for inland
areas overnight.

Gusty west winds continue with gusts still up to
45 mph in the Coachella valley and up to 55 mph over mountain
ridges and through the Banning Pass, as of 8PM. Winds will
gradually weaken throughout the night with most areas likely
gusting below 15 mph by sunrise, with some typical local
exceptions. There maybe even a brief reversal to an offshore flow
in the morning before the onshore sea breeze returns in the
afternoon, though less strong as today.

Highs Saturday remain on track to be slightly warmer than today`s.



From previous discussion as of 1:43 PM...
The upper level low moving through California today will quickly
move into Nevada Saturday. That will bring a brief period of
northerly winds Saturday morning. Those northerly winds will be
mostly on the coastal mountain slopes and below the Cajon Pass.
The offshore winds may result in quicker clearing of any clouds
that develop in the valleys and Orange County. Onshore flow will
return by the afternoon. High temperatures will warm a few degrees
west of the mountains tomorrow, with the deserts a few degrees
cooler. By Sunday, minimal change in temperatures expected near
the coast with a few degrees of warming further inland.

A broad area of low pressure extending from the Intermountain West
will dig south early next week, which will bring slightly cooler
conditions on Monday. For the middle to end of next week, more
uncertainty enters the forecast. Ensemble guidance is about 50/50 on
whether or not a trough or a ridge will be the main influence on
Southern California`s weather. This is emphasized by the 20 degree
spread in high temperatures between the 90th and 10th percentiles of
temperature guidance. If a more troughy pattern materializes near
California, it`s possible tropical moisture may be drawn northward
into the Southwestern United States, bringing an increase in cloud
coverage and a slight chance of showers. Right now the forecast
closely follows the NBM for the middle to end of next week.


&&

.AVIATION...
040300Z....Coasts/Valleys...Patchy low clouds based 2000-2500 ft are
banking along inland valley foothills. Clouds are expected to remain
intermittent and patchy in coverage throughout the night across the
coastal basin. Some local vis reductions and -DZ may be possible,
especially for the foothills and Inland Empire. The few clouds that
remain after sunrise should mostly scatter out between 15-17z Sat.
Slightly greater coverage and lower bases return 02-04z Sun into
coastal SD County.


Mountains/Deserts...West winds with gusts 25-35, locally to 50 kts,
are being observed this evening over mountain ridges, desert slopes
and desserts. Strong winds will gradually subside overnight.
Otherwise, mostly VFR with a few clouds forming over mountain crests.

&&

.MARINE...
This evening, Northwest winds sustained winds 20 to 25 kts, with
occasional gusts over 30 kts are generating choppy seas 5-8 feet and
yielding hazardous conditions for small craft. Winds weaken
gradually overnight. No hazardous marine conditions are expected
Saturday through Tuesday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 11 PM PDT this evening for Apple and Lucerne
     Valleys.

     Wind Advisory until 5 AM PDT Saturday for San Diego County
     Deserts-San Gorgonio Pass near Banning.

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


&&

$$

PUBLIC...Westerink/CO
AVIATION/MARINE...Westerink