699
FXUS66 KSGX 250529
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
929 PM PST Mon Nov 24 2025

.SYNOPSIS...
A gradual warming is expected through the middle of the week, with
above normal high temperatures expected Tuesday through Friday. Weak
to moderate Santa Ana winds are expected Tuesday through Thursday,
with the strongest winds expected on Wednesday. A trough of low
pressure will bring cooler weather and a chance of showers for the
weekend into early next week.

&&

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

Satellite at 9 PM was showing mostly clear skies across the area
with only a few patches of low clouds over the coastal waters. Low
clouds will become a bit more widespread overnight along the
coast and in portions of the western valleys, with patchy dense
fog possible near the coastal mesas and higher coastal terrain.
Noticeable warming is expected into Tuesday, with highs 5 to 10
degrees warmer than today west of the mountains and 2 to 5 degrees
warmer than today in the deserts.

From previous discussion issued 2 PM November 24...

The high pressure ridge over the eastern Pacific will continue to
build over the west coast, keeping the marine layer very shallow and
continuing a warming trend through Wednesday. At the same time, a
sfc high moves into the Great Basin setting up offshore pressure
gradients which will produce Santa Ana winds across SoCal. Northeast
to east winds will begin to develop early Tuesday, strengthening
into Wednesday then weakening on Thursday. The winds will be
strongest on wed and a lack of upper level support means that the
strongest winds will be mostly restricted to the passes, canyons and
coastal foothills. In these wind-prone areas, we can expect wind
gusts of around 35-45 mph on Wednesday. The upper level ridge and
the Santa Ana winds will combine to bring significantly warmer and
drier conditions especially west of the mtns.

Patches of low clouds and fog will likely return to the coastal
areas tonight but the developing offshore flow could cause it to
clear out before sunrise tomorrow.

Wednesday will likely be the warmest day with daytime high
temperatures 10-15 degrees above seasonal averages in the inland
valleys and 5-10 degrees above seasonal averages elsewhere.
Temperatures will lower a little on Thanksgiving (but will remain
several degrees above seasonal averages) as the the upper level
ridge begins to weaken and shift east.

A vigorous shortwave trough moving inland to the north on Friday
will usher in a pattern change which will see a return of low
pressure troughing over the western states. This will bring a
cooling trend and a return of onshore flow for Friday into early
next week. While the longwave pattern is likely to result in broad
troughing over the western US, the timing and trajectory of low
pressure systems embedded in this pattern are highly uncertain due
to the spread among model solutions. As a result, confidence in
forecast details is not high.

Since the last model run, the number of ensemble members indicating
precip for next Sun-Mon is increasing so confidence is growing that
another round of rainfall/snow is on the way. For now, precip
estimates are still very uncertain but indications are that the
system producing the rain/snow will be colder so snow levels could
fall to 5000 ft or lower. Daytime temperatures in the valleys and
coastal areas could be as low as the upper 50s for next Sunday.

&&

.AVIATION...
250400Z...Coasts...Patchy low clouds based 500-800 ft MSL over
coastal waters expected to push into coastal San Diego County within
the next few hours, then into coastal Orange County 06-09Z. Coverage
of BKN cigs will remain inconsistent overnight with only a 60%
chance of any BKN cigs at coastal TAF sites, but vis reductions are
likely where clouds occur. Minor vis reductions (2-5SM) to sea level
and 1-2SM to locally dense FG (1/4SM) along elevated coastal
terrain. Clouds scatter to the coastline 12-15Z for most areas.
Slight chance (20-30%) of BKN cigs returning to coastal areas after
03Z Wed. Any cigs would be less than 500 ft MSL and would create vis
reductions.

Valleys/Mountains/Deserts...VFR conditions expected through Tuesday
evening. NE winds locally gusting to 25 kts along coastal slopes of
the mtns will expand to include adjacent foothills and portions of
the Inland Empire after 18Z Tue.

&&

.MARINE...
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...CO/PG
AVIATION/MARINE...KW