San Diego Weather at Mission Trails, CA

662
FXUS66 KSGX 191133
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
333 AM PST Mon Jan 19 2026

.SYNOPSIS...
Warm and dry weather will continue through Tuesday, with high
temperatures 5 to 15 degrees above normal. Marine layer low clouds
and fog could return to the coastal areas as early as tonight into
Tuesday morning but confidence is low. Offshore flow briefly
returns tonight into Tuesday morning with breezy conditions below
the passes, weakening Tuesday night. Chances for Coastal low
clouds and fog improve each night and morning for Tuesday night
through the end of the week. A cooling trend begins Wednesday and
continues through Friday as a low pressure system moves in from
the Pacific, helping build the marine layer even further and
extend the low clouds and fog inland. This low will bring a
10-15% chance of precipitation for Friday into Saturday.

&&

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

This morning, skies are clear except for a few high clouds. There
is no marine layer presence in spite of the offshore flow continuing
to weaken. Dry conditions at the surface extend from inland all
the way to the coast in many areas. Relative humidity is high at a
few coastal locations so the chances for patchy low clouds/fog
can`t be eliminated. High-resolution models show chances for
marine layer clouds/fog returning to the coastal areas as early as
tonight but probabilities are low.

Offshore flow strengthens again late tonight into Tuesday,
effectively preventing a marine layer return until Tuesday
night/Wednesday morning. Offshore flow weakens again late Tuesday
but chances remain low for a marine layer return until Wednesday
night when onshore flow allows the dry air at the surface to be
displaced farther inland.

A high pressure ridge persists over SoCal through Wednesday,
weakening over time as a low pressure system approaches from the
west. Daytime high temperatures remain 5-15 degrees above normal
through Tuesday for the coastal areas and inland valleys.
Temperatures are a little lower on Wednesday as onshore flow
begins to spread the marine air inland.

Temperatures lower more significantly for Thursday through
Saturday as a low pressure system from the Pacific displaces the
high pressure ridge and brings cooler, more moist air to the
entire region along with widespread clouds. This system will also
bring small chances for light precipitation Friday into Saturday,
mostly for the mountains westward to the coast. Currently,
chances for measurable precipitation in any 6-hour period remain
below 25%. A significant number (about 30 percent) of ensemble
members show measurable precipitation for Friday and Saturday.

By early Sunday, the low has moved east and weakened while high
pressure begins to rebuild over the West Coast. This will bring a
return of fair weather with temperatures again on the rise. By
next Monday, high temperatures are once again as much as 8 degrees
above normal for areas west of the mountains.

&&

.AVIATION...
191030Z...Mostly clear skies today and tonight. North and east winds
to increase after 00Z for pockets of foothills downstream of
mountain passes with gusts up to 30 kts.

At the coast, patchy FG with VIS < 1/2SM to develop after 02Z, 30-
40% chance for FG impacts for the coastal TAF sites.

&&

.MARINE...
Patchy dense fog tonight into Tuesday (35-45% chance), reducing vis
locally below 1 nautical mile. Otherwise, no hazardous marine
conditions are expected through Friday.

&&

.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...PG
AVIATION/MARINE...MM