467
FXUS66 KSGX 201203
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
403 AM PST Tue Jan 20 2026

.SYNOPSIS...
Above average temperatures and weak offshore flow will continue
today. For tonight into Thursday, the marine layer will slowly
deepen with low clouds and fog spreading into coastal areas by
early Wednesday and into portions of the valleys for early
Thursday. A low pressure system from the northwest will bring
cooling for Wednesday through Friday along with a chance of
showers for late Thursday through Friday. Then drier and warmer
for the weekend into early next week.

&&

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

.SHORT TERM (Today through Thursday)...
There is weak east to northeast lower level flow with patchy low
clouds and fog mostly remaining off the coast and over portions of
the coastal waters. A weak coastal eddy may develop today or
tonight with coastal low clouds and fog increasing in coverage
over the coastal waters into coastal areas for tonight into
Wednesday morning. The gradual deepening of the marine layer is
expected to continue into Thursday.

High temperatures for today will be as much as 8 to 12 degrees
above average for the inland valleys with high temperatures
ranging from around 70 near the coast to the mid 70s to lower 80s
for the valleys with the lower deserts in the upper 70s. High
temperatures on Wednesday will be a few to around 5 degrees cooler
than today with Thursday as much as another 4 to 8 degrees cooler
for the mountains and valleys.

A closed low pressure system developing off the California coast
on Wednesday will bring a chance of showers to southwestern
California some time around late Thursday through Friday.

&&

.LONG TERM (Friday through Monday)...
Chances for showers will continue into Friday. Chances for one-
half inch or more of rainfall for Thursday through Friday ranges
from around 10 percent near the coast to around 20 percent for the
mountains. Snow levels will be around 6500 to 7000 feet.

High temperatures will continue to cool through Friday with Friday
high temperatures a few degrees above average for the deserts and
a few to around 5 degrees below average elsewhere. High
temperatures on Friday will be mostly in the 60s for the coast and
valleys and in the lower 70s for the lower deserts.

There will be drying and gradual warming for the weekend into
early next week with high temperatures on Monday of next week a
few to around 5 degrees above average. High temperatures on Monday
of next week will range from the mid to upper 60s near the coast
to the lower to mid 70s for the valleys and inland Orange County
with the lower deserts in the lower to mid 70s.

&&

.AVIATION...
201030Z...Coast...Patchy low clouds and FG over coastal waters could
briefly touch the coast through 16Z. 20% chance of impacting coastal
airports with bases 400 feet MSL and vis 0-2SM. Higher confidence
for better coverage of low clouds after 02Z tonight into Wednesday.
Bases would be around 400-700 feet MSL and vis 5SM or above.

Valleys/Mountains/Deserts...North and east winds remain elevated for
pockets of foothills downstream of mountain passes with gusts 25-35
kts early this morning before relaxing 15-18Z.

&&

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

&&

.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...17
AVIATION/MARINE...MM

NWS San Diego (SGX) Office