Alpine, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

051
FXUS66 KSGX 240430
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
830 PM PST Fri Jan 23 2026

.SYNOPSIS...
Isolated light showers will continue into Saturday for the
mountains westward. Dry weather with a gradual warming trend is
expected for Sunday through Friday. Weak to locally moderate
Santa Ana winds develop for late Saturday night through Monday
afternoon mostly gusting to 45 mph or less. Weaker offshore flow
will persist Tuesday and Wednesday. Lower confidence in the
weather pattern late in the week with some ensemble members
showing precipitation, though the majority remain warm and dry.

&&

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

Evening update...
Water vapor imagery shows the upper level low approaching the
central Baja California coast. Scattered showers developed over
inland San Diego County earlier this afternoon but have since
dissipated. Another short wave on the back side of the upper
trough over the Great Basin is currently digging south through
California. This will provide another burst of lift, and with
relatively deep moisture (up to 700 mb) still in place, should be
enough to produce drizzle or light showers through Saturday
afternoon, generally for Orange and San Diego Counties. While the
snow level will finally lower to around 6,500-7,000 ft tonight,
mountain communities at these elevations will be mostly dry, so
don`t expect much more than the occasional flurry at best.

Once this short wave passes late Saturday and surface high
pressure settles over the Great Basin, there will be a quick
transition to offshore flow for drier weather beginning Sunday.
On Saturday, highs will still be around 3 to 5 degrees below
normal. Areas west of the mountains will warm to around normal on
Sunday, but the mountains and deserts remain slightly below normal as
cool air is ushered in from the north.

Previous discussion...
The first pulse of wind arrives Saturday night and remains elevated
through Sunday morning. These northeast winds could bring gusts up
to 50 mph out of San Bernardino County foothills, Cajon Pass and
Santa Ana Mountains. Winds relax a bit Sunday afternoon, then a
second weaker pulse brings elevated east winds into the San Diego
and Riverside County foothills, gusting to 40 mph through Monday.
Relative humidity will drop quickly for inland areas as the winds
arrive - as low as 10% in certain inland areas.

Medium range models show high confidence for a ridge to re-build
over the mountain West, with a center axis along the Nevada-Utah
border on Tuesday, then flattening out late week. High temperatures
will remain at or slightly average, in the upper 60s and low 70s
throughout the coastal basin with passing high clouds moving
through. Weak offshore winds continue through the week, keeping
relative humidity low for inland areas, while the coast experiences
weak onshore flow. Increasing cloud cover and slightly cooler
temperatures may be in store for Thursday and Friday as 20% of WPC
model ensemble clusters show a closed low developing in the Pacific
and moving through the West Coast.

&&

.AVIATION...
240330Z....Coasts/Valleys...Various cloud layers with one deck
around 1500ft MSL, one around 3000-4000ft MSL, and another deck
around 9000-10,000ft MSL. These conditions will generally prevail
through 18z, with valleys and inland areas experiencing some reduced
VIS down to 2-5SM between 10-18z. Iso -SHRA possible through
Saturday morning for the coastal sites, but shouldn`t be impactful.
Low clouds will scatter out by 19z for coastal sites with FEW-SCT
AOA 10,000ft MSL prevailing thereafter. Clearing of the low clouds
for inland areas may occur a bit slower, closer to 20-22z. Offshore
flow returns Saturday night, likely to prevent any low clouds from
redeveloping/impacting any TAF sites through Sunday morning. LLWS
into the IE possible, generally after 05z.

.Mountains/Deserts...SCT-BKN clouds around 10,000ft MSL and VFR
conditions expected through Saturday afternoon, especially in San
Diego County. BLDU possible late Saturday night into Sunday morning
with gustier easterly winds. Wind through the mountain passes may
exceed 30kts at times. Mod up/downdrafts near the mountains after
03z 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...None.
PZ...None.

&&

$$

PUBLIC...SS/Westerink
AVIATION/MARINE...Zuber