540
FXUS66 KSGX 250433
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
833 PM PST Sat Jan 24 2026

.SYNOPSIS...
Weak to locally moderate northerly Santa Ana winds will develop
overnight and continue into Sunday morning, turning easterly for
Sunday night into Monday. Weaker offshore flow will follow through
at least Wednesday for gradual warming and dry conditions.
Confidence in the late week pattern is still uncertain with the
potential for a low pressure system to bring some cooling and a
return of onshore flow, or for high pressure and offshore flow
maintaining warmer and dry weather.

&&

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

Evening update...
Surface pressure gradients are trending offshore but remain weak
at this time, around -4.6 mb SAN-TPH. Wind gusts below the Cajon
Pass are only around 25-35 mph at this time. Gradients and winds
are forecast to strengthen overnight with winds spreading into the
Inland Empire and Santa Ana Mountains. A Wind Advisory was issued
earlier valid through 1 PM Sunday for the San Bernardino
Mountains, Santa Ana Mountains, and Inland Empire, where gusts up
to 45-55 mph are expected in the wind prone locations. Otherwise
expect remaining low clouds to clear out overnight. It will be
cool in the wind- sheltered inland valleys tonight with lows
locally in the low to mid 30s.

Previous discussion...
North winds weaken Sunday afternoon, then re-intensify out of the
east Sunday night as the strong surface high (around 1042 mb) drops
down into the southern Great Plains, thereby increasing our
East/West pressure gradient. This gradient remains strong through at
least Tuesday morning, yielding to periods of strong easterly wind
gusts through the Banning Pass and Peninsular Range foothills around
30-45 mph during the early part of the weak.

Very dry air will accompany these Santa Ana winds, dropping humidity
down to 20-30% tonight and ultimately down to 10% by Sunday where
the winds blow. Morning temperatures will also be on the colder side
for Southern California standards, with moderate chances for Sunday
morning lows dipping below 35F in the interior valleys and good
confidence for below freezing temperatures in the high desert.

Medium range ensembles show high confidence in the redevelopment
of a ridge over the mountain West, with a center axis over eastern
Washington, Oregon and California on Tuesday. High temperatures
will only reach a few degrees above average - in the low 70s for
the coastal basin - as high clouds will be passing through
intermittently and as mid-level temperatures will remain cool,
despite the ridge.

Wednesday, around 30% of WPC model ensemble cluster runs show a
closed low developing in the Pacific and moving though Southern
California. In all ensemble runs, this trough is weak and embedded
within the greater stubborn West Coast ridge. High temperatures may
cool slightly Thursday and Friday if this scenario plays out, though
the chances for any precipitation are close to zero. Most ensemble
clusters then agree that the ridge will re-intensify to a certain
extent into next weekend, bringing temperatures back above average.

Weak offshore winds continue through the end of the week if the
trough referenced earlier doesn`t form, keeping relative humidity
low for inland areas, while the coast experiences weak onshore
flow.

&&

.AVIATION...
250400Z...Patches of BKN low level clouds along and west of coastal
slopes will clear out of most areas by 06Z Sun. Otherwise, gusty
north to northeast winds along coastal slopes, and downwind of the
Cajon Pass into the Inland Empire through early Sunday afternoon.
Gusts 25-40 kts along coastal slopes (locally 45 kts through the
Cajon Pass) and 15-30 kts for portions of the Inland Empire. LLWS
downwind of the Cajon Pass and VCTY KSNA possible through 12Z Sun.

&&

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

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 1 PM PST Sunday for San Bernardino County
     Mountains-San Bernardino and Riverside County Valleys-The
     Inland Empire-Santa Ana Mountains and Foothills.

PZ...None.

&&

$$

PUBLIC...SS/Westerink
AVIATION/MARINE...KW

NWS San Diego (SGX) Office