443
FXUS66 KSGX 021711
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
911 AM PST Tue Dec 2 2025

.SYNOPSIS...
The marine layer will deepen overnight into Wednesday morning before
becoming shallower again for Thursday into early next week. Areas of
drizzle or light rain near the coast are possible tonight into
Wednesday, with no impacts expected. Wednesday will be a few
degrees cooler than today, before warmer conditions Thursday into
early next week. The pressure gradient will rapidly switch from
onshore to offshore for the middle to end of the week with periods
of gusty Santa Ana winds.

&&

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

Visible satellite at 9 AM was showing mostly clear skies across the
area, the only exception was a patch of fog over northern Orange
County and low clouds over the coastal waters. The marine layer is
expected to rapidly deepen as a low pressure system moves south
into the Great Basin tonight. By Wednesday morning, the marine
layer is expected to be about 4500 ft deep with low clouds
reaching the coastal slopes of the mountains. There could be some
light showers or patchy drizzle late tonight into early Wednesday
morning for the inner coastal waters into adjacent coastal areas
with the chance of measurable rainfall less than 10 percent.

As the upper level low digs into the Great Basin a 1030 mb surface
low will develop. This will bring periods of gusty offshore winds
to foothills and coastal mountain slopes; warming conditions; and
mostly clear skies across the area. Gusty north winds will
develop through and below the Cajon Pass on Wednesday afternoon
with more widespread and stronger northeasterly winds for
Wednesday night along and below the coastal slopes of the
mountains with the stronger gusts to around 45 mph. Northeast to
east winds will continue for Thursday into Friday morning, but
with decreasing coverage and strength. Gusts on Friday are
expected peak around 35 mph. Lowest daytime humidity on Thursday
for the valleys and inland coastal areas will fall to 15 to 20
percent and 20 to 25 percent Friday afternoon.

Highs today are expected to be near normal for this time of year,
with some locations a little warmer than normal and others a little
cooler. Few degrees of cooling is expected into Wednesday, with
highs a few degrees below average. A gradual warming will occur
Thursday, with further warming expected through the weekend into
early next week. By Tuesday, highs will be 10 to 15 degrees above
average for inland areas.

&&

.AVIATION...
021700Z....Coasts/Valleys...A stubborn patch of FG in the vcty KSNA
will clear out within the next hour. Otherwise, SKC through the
afternoon. Low clouds based 600-1200 ft MSL return to San Diego
County 00-03Z Wed. Bases will rise steadily overnight to 2000-2500
ft MSL as coverage expands to include the entire coastal basin.
Patchy -DZ expected, especially near the coastline from 10-16Z.
Clouds scatter out 15-18Z.

Mountains/Deserts...VFR conditions through the period with FEW-SCT
high clouds AOA 20 kft after 21Z. Westerly winds gusting 25-35 kts
through mountain passes and along east-facing slopes after 03Z Wed.

&&

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

&&

.BEACHES...
Astronomical high tides are forecast to occur each morning Wednesday
through Friday, threatening minor tidal overflow and beach erosion.
Chances of these impacts are higher Wednesday and Thursday mornings
as elevated surf up to 4-6 feet combines with the high tides,
especially in San Diego County. Check the Coastal Hazard Message for
details.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from this evening through Friday morning
     for Orange County Coastal Areas-San Diego County Coastal
     Areas.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE/BEACHES...KW