200
FXUS66 KSGX 201044
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
244 AM PST Thu Nov 20 2025

.SYNOPSIS...
Scattered showers over the coastal waters will spread into
coastal areas early this morning. The next low pressure system
from the northwest will bring more widespread showers late
this afternoon into Friday. With snow levels lowering to around
6000 feet late tonight, there could be moderate to heavy snowfall
in the mountains above 6500 feet. For Friday night into Saturday,
the most widespread showers are expected for the mountains with
snow levels rising to around 7000 feet by late Saturday afternoon.
Then dry with warming for Sunday through Thanksgiving with
Thanksgiving high temperatures a few degrees above average to 4 to
8 degrees above average for the inland valleys and portions of
the mountains.

&&

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

.SHORT TERM (Today through Saturday)...
Early this morning, scattered showers will develop over the
coastal waters and spread into coastal areas with rainfall of
one-tenth inch or less. For this afternoon, scattered mostly
light showers could develop in advance of a colder low pressure
system moving southward just off the California coast.

The most widespread and heaviest precipitation is expected with
the cold front this evening with showers continuing overnight.
There is also a slight chance of thunderstorms for tonight. The
snow level will rise to around 7000 feet for late this afternoon,
then fall to around 5500 to 6000 feet for early Friday morning.
The snow level will then gradually rise to around 7000 feet for
late Saturday afternoon. South to southeast winds will develop
and strengthen ahead of the cold front for late this afternoon and
evening across the coastal waters and adjacent coastal areas with
gusts to 25 to 30 mph.

Through Saturday, rainfall and liquid-equivalent above the snow
level could range from around 1 inch at the coast to 1.5 to 2
inches for the mountains with locally greater amounts. Chances for
one inch or more of rainfall or liquid-equivalent above the snow
level through Friday night ranges from around 30 percent near the
coast to 50 to 70 percent in the mountains. Through Friday
afternoon, snowfall of 3 to 6 inches is expected from 6000 to 7000
feet, 6 to 10 inches from 7000 to 7500 feet, and 10 to 14 inches
above 7500 feet. Scattered snow showers will continue for Friday
night into Saturday with additional snowfall of 2 to 5 inches.

&&

.LONG TERM (Sunday through Wednesday)...
There will be high pressure off the West Coast with generally
northwest flow aloft across California. There will be dry weather
with a warming trend for Sunday through Thanksgiving. High
temperatures on Sunday of a few to around 5 degrees above average
will warm through Thanksgiving with Thanksgiving high temperatures
a few degrees above average to 4 to 8 degrees above average for
the inland valleys and San Diego County mountains.

High temperatures on Sunday will range from the lower to mid 60s
near the coast to the mid 60s to around 70 for the valleys with
the lower to mid 70s for the lower deserts. High temperatures on
Thanksgiving will range from around 70 near the coast to the 70
for the valleys with the mid to upper 70s for the lower deserts.

&&

.AVIATION...
201030Z...Increasing low clouds mainly between 2500-3500 feet MSL
along with SCT -SHRA in coastal areas through 14Z. SCT-BKN low
clouds 2500-3500 feet MSL continue into afternoon, with increasing
-SHRA. Cloud bases will lower to 2500 feet MSL, then 1500 feet as a
band of -RA moves southeast through the region starting at 22Z vcnty
KSNA and ending around 09Z vcnty KSAN, but with SHRA following the
band. +RA and any TSRA (15% chance) would briefly drop cigs below
1000 feet MSL and vis 1-5SM. Widespread mountain obscuration during
the band`s passage.

&&

.MARINE...
Strengthening southerly winds gusting to 25 knots this afternoon
will turn westerly tonight, generating choppy seas. Check the Small
Craft Advisory for details. There is also a slight chance of
thunderstorms late this afternoon through Friday afternoon. Any
thunderstorm could bring lightning, gusty winds, choppy seas, and a
waterspout.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Storm Warning from 4 PM this afternoon to 4 PM PST Friday
     for Riverside County Mountains-San Bernardino County
     Mountains above 6500 feet.

PZ...Small Craft Advisory from 4 PM this afternoon to 1 AM PST
     Saturday for Coastal Waters from San Mateo Point to the
     Mexican Border and out to 10 nm-Waters from San Mateo Point
     to the Mexican Border Extending 10 to 60 nm out including
     San Clemente Island.

&&

$$

PUBLIC...17
AVIATION/MARINE...MM