513
FXUS66 KSGX 211100
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
300 AM PST Fri Nov 21 2025

.SYNOPSIS...
Showers and isolated thunderstorms continue through late this
morning, followed by scattered showers into Saturday. Snow levels
will remain near 6500 ft through Saturday morning. Drier weather
with a very slow warming trend sets in for the end of the weekend
into early next week, warming to above normal by Thursday. There
is the potential for weak Santa Ana winds by the middle of next
week.

&&

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

Numerous showers are ongoing this morning with the occasional
lightning strike. The most widespread activity is occurring north
of San Diego County, closer to the surface low and upper level
vort max. This wave rotates north through the morning as the
center of the upper low, which is currently off the Central CA
coast, digs southward. With less forcing overhead, showers will
become more scattered and weaker by this afternoon, and
thunderstorm chances drop below 15%.

Precipitation begins to wind down late today into tonight as the
upper level low continues to progress southward, with showers
becoming more isolated. Then as the low moves eastward across
northern Baja, wrap-around moisture and light precipitation will
move into the area, most widespread across the mountains and
deserts. Showers finally come to an end Saturday evening as the
low moves off to the east. For the remainder of today and
Saturday, additional rainfall amounts will range from around
0.10-0.30" for the coasts and valleys, 0.20-0.70" in the
mountains, locally around 1" where wrap-around precipitation
occurs, and 0.10-0.50" in the deserts, again highest where wrap-
around occurs, potentially over 1" (50-60% chance) along the
desert foothills in Southern San Diego County. The snow level
remains near 6500 ft through Saturday morning, then rises to
around 7000 ft Saturday afternoon. Additional slow amounts above
6500 ft range from 2-5", locally up to 9" on the east slopes of
the eastern San Bernardino Mountains. With the bulk of the
snowfall happening today, opted to keep the Winter Storm Warning
only through 4 PM this afternoon, though on and off light snow
showers will persist into Saturday afternoon.

Once the upper low is out it is back to our regularly scheduled
Southern California weather. Dry northwest flow develops over the
region Sunday and Monday, followed by weak ridging for midweek.
With the storm track back to our north, cold air eventually
settles into the Great Basin behind a pair of short waves, driving
surface high pressure to our north and offshore flow across So
Cal. CW3E West-WRF has around a 20% chance of a weak to moderate
Santa Ana event on Tuesday, increasing to a 40% chance on
Wednesday. Gradients and winds are forecast to weaken on
Thanksgiving Day, though with ridging overhead it`ll be another
warm and dry holiday with highs anywhere from 3-10 degrees above
normal.

Ensembles are showing the potential for another trough and
precipitation sometime late in the week or early next week, though
as to no surprise there are vast differences in the timing and
track of this system.

&&

.AVIATION...
211030Z...BKN-OVC low clouds will vary between 700-3500 feet MSL
this morning. SHRA and a slight chance of TSRA with cigs in RA
dropping below 1500 feet MSL and vis 1-5SM. Mountains obscured in
RA/SN/FG with improving conditions after 17Z. SHRA/SHSN will
decrease and cigs and vis will lift during the day. Easterly winds
gusting 20-30 knots developing after 23Z in foothills and locally
into inland valleys. Isold SHRA/SHSN to continue this afternoon into
Saturday, but with bases mostly above 2500 feet MSL.

&&

.MARINE...
There is a chance of thunderstorms this morning. Any thunderstorm is
likely to produce lightning, gusty variable winds and briefly choppy
seas. There is also a slight chance of a waterspout.

&&

.BEACHES...

There is a chance for lightning (20-30%) this morning.


&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Storm Warning until 4 PM PST this afternoon for Riverside
     County Mountains-San Bernardino County Mountains.

PZ...None.

&&

$$

PUBLIC...SS
AVIATION/MARINE/BEACHES...MM