648
FXUS66 KSGX 281657
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
857 AM PST Fri Nov 28 2025

.SYNOPSIS...
Through Sunday, stronger onshore flow and a weak coastal eddy will
bring gradual deepening of the marine layer with cooling spreading
inland. Night and morning coastal low clouds and fog will increase
in coverage and spreading a little farther inland each night
through the weekend. Weak northerly flow on Monday will bring
warming for the coast and valleys and cooling inland. A low
pressure system moving southward along the West Coast will bring
cooling for Wednesday and Thursday. If the track is far enough to
the west, there would also be a chance of showers.

&&

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

Morning Update...

Very low marine layer clouds that brought brief dense fog
conditions to extreme northwestern Orange County this morning have
pushed out to sea, and the Dense Fog Advisory that was in effect has
been allowed to expire. Otherwise, mostly clear skies expected
today with no other changes to the forecast. See the previous
discussion for more details about the upcoming forecast.

From previous discussion...

.SHORT TERM (Today through Sunday)...
A weak coastal eddy has developed with local higher-resolution
model guidance showing the eddy continuing into Sunday morning
with slow deepening of the marine layer along with increasing
coverage of night and morning coastal low clouds and fog.

The lower level flow is still weakly offshore, though trending
weakly onshore. Satellite imagery shows low clouds and fog over
the coastal waters remaining off the coast of San Diego and
southern Orange Counties and drifting farther off the coast with
the low clouds and fog extending locally inland into northern
Orange County and southern Los Angeles Counties. The fog is
locally dense with visibility of one-quarter mile or less at Long
Beach and Los Alamitos.

As onshore flow returns and the marine layer slowly deepens,
cooling will spread inland through the weekend. High temperatures
today for the coast and valleys will be as much as 4 to 8 degrees
cooler than Thanksgiving with the greater cooling on Saturday for
the mountains and high desert. The cooling will continue for the
coast and valleys on Sunday as the marine layer deepens. High
temperatures on Sunday will be a few degrees below average for
coastal areas with the mountains and deserts as much as 4 to 8
degrees above average. High temperatures on Sunday will range from
the lower to mid 60s near the coast to around 70 for the valleys
with the 70s for the lower deserts.

&&

.LONG TERM (Monday through Thursday)...
For Monday, northerly low level flow will bring cooling of 4 to 8
degrees for the mountains and high desert and warming of a few
degrees for the coast and valleys. The coast and valleys will cool
a few degrees on Tuesday and the mountains and high deserts will
warm a few degrees as the lower-level northerly flow weakens.

For Wednesday and Thursday, a low pressure system moving southward
in the vicinity of the West Coast will bring cooling. Depending
on the track and evolution of this system, it could also bring a
chance of precipitation.

&&

.AVIATION...
281600Z....Coasts/Valleys...Low clouds based around 400-700ft MSL
have been hanging just offshore, unlikely to impact any TAF sites
this morning. Low clouds have a better chance to move ashore tonight
(45-60% chance) after 02z Sat with bases slightly higher than this
morning, 700-1200ft MSL. Clouds will push 5-10 miles inland.
Localized VIS reductions down to 4-6SM, with 1-3SM for elevated
coastal terrain. Any low clouds should begin clearing to the coast
around 16-17Z.

.Mountains/Deserts...VFR conditions expected through the TAF
period.

&&

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

&&

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

&&

$$

PUBLIC...Munyan
AVIATION/MARINE...Zuber