583
FXUS66 KSGX 230956
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
256 AM PDT Sat May 23 2026

.SYNOPSIS...
Near average temperatures through the weekend with below average
temperatures expected next week. Low clouds and fog will be present
from the coast to the valleys each night and morning, lingering into
the afternoon at times along the coast. Increased westerly winds
expected Tuesday through potentially Thursday for the mountains and
deserts.

&&

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

Marine layer low clouds have filled in over the coastal areas and
western valleys and spread into the southern and western parts of
the Inland Empire this morning. Clouds will continue to push
several more miles inland in the Inland Empire through sunrise,
then slowly clear black towards the coast through late morning.
Elsewhere skies will remain clear.

Weak troughing along the West Coast will maintain cool weather
with high temperatures near to slightly below normal across the
region. Low clouds will spread into the inland valleys again
tonight into Sunday morning, with limited clearing at the coast
Sunday afternoon as the marine layer continues to deepen. A weak
upper level low will move through late Sunday into Monday, helping
the marine layer deepen further and bringing greater cooling for
Memorial Day, when high temperatures are forecast to be around 3-7
degrees below normal for the mountains westward, and near normal
in the deserts. There is a small potential for drizzle in the
morning, then parts of the coasts and valleys may remain at least
partly cloudy through the day. It won`t exactly be beach weather
with low clouds hanging around and highs in the upper 60s.

Ensembles have come into better agreement with the progression of
the upper low dropping down midweek. This closed low will move
into the Pacific Northwest by Tuesday morning, digging south
somewhere into CA or NV Wed and Thu before ejecting eastward late
in the week. The marine layer will continue to deepen, extending
into the coastal mountain slopes each morning. Depending on the
track of the trough axis/vort max, we may receive light
precipitation from the coasts to the mountains. A more westerly
track, which would favor light precipitation, currently accounts
for around 45% of the ensemble space. Even then, mean
precipitation within that cluster is less than 0.10". Gusty
southwest to west winds are also expected with this system
midweek, though again the further west track would favor stronger
winds versus a more easterly/inside track. Wind gusts in the
mountains and deserts are currently forecast to be around 35-45
mph with isolated gusts in excess of 55 mph below the passes
Tuesday evening, weakening slightly on Wednesday. By Wednesday,
when the upper low is closest, high temperatures will be around
10-15 degrees below normal inland, and around 3-5 degrees below
normal near the coast. Minor warming on Thursday as the low begins
to shift east, then continued warming into Saturday with high
temperatures returning to near normal.

&&

.AVIATION...
231200Z...Coast/Valleys...Low clouds based 2000-2400 ft MSL have
filled in across most of the coastal basin this morning, with a few
gaps in the northeastern Inland Empire. With CIGs, VIS locally
reduced 3-5SM in BR in far inland valleys, and 0-3SM where clouds
intersect higher terrain. Inland valleys scatter out 15-16z, coastal
areas 17-18z Saturday. Clouds redevelop and push back ashore after
00z Sunday with similar bases.

Otherwise, mostly clear and VFR conditions through Sunday morning.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...SS
AVIATION/MARINE...Munyan