470
FXUS66 KSGX 030459
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
859 PM 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...

This evening, the marine layer is now about 4000 ft deep and areas
of low clouds have formed from the coast to the mtn foothills. By
Wednesday morning, the marine layer is expected to be about 4500
ft deep and the low clouds are likely to fill in all areas west of
the mtns. If the saturated layer becomes thick enough, there
could be some drizzle west of the mtns later tonight. Sfc pressure
gradients continue to trend onshore and westerly winds are
locally gusting 25-45 mph in the wind-prone passes and canyons at
this hour.

From previous discussion...
As the upper level low moves southward into the Great Basin, a
1030 mb surface low will develop. This will bring periods of gusty
Santa Ana 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 into Thursday morning along and below the
coastal slopes of the mountains with peak gusts 40 to 50 mph,
locally up to 55 mph. Northeast to east winds will continue for
Thursday afternoon into Friday morning, but with decreasing
coverage and strength. Gusts on Friday are expected peak at 35 to
40 mph. Lowest daytime humidity on Thursday and Friday for the
valleys and inland coastal areas will fall to 15 to 20 percent.

A 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...
030400Z....Coasts/Valleys...Patchy low clouds based 2200-3200 ft MSL
with tops to 4000 ft MSL will continue to move to cover the coastal
basin by about 10Z this evening. Patchy -DZ expected, especially
near the coastline 10-16Z, bringing areas of lowered vis 4-6 SM on
occasion. Clouds will intermittently scatter out overnight, with
fuller clearing from east to west 14-18Z. North to northeast winds
gusting 20-30 kts through and downwind of the Cajon pass after 17Z
(including vcnty KONT) and continuing in areas through the
TAF period.

Mountains/Deserts...VFR conditions through the period with FEW-SCT
high clouds AOA 20 kft. West winds gusting 25-40 kts through
mountain passes and along east-facing slopes will weaken 15-18Z,
before turning north to northeast and strengthening again along the
coastal slopes and foothills. Mod up/downdrafts near mtns.

&&

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

&&

.BEACHES...
High tides of 6.5 to 7.5 feet 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, mostly 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 through Friday morning for Orange County
     Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE/BEACHES...CSP