508
FXUS66 KSGX 220514
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
914 PM PST Fri Nov 21 2025

.SYNOPSIS...
Rain and snow showers are expected to increase in coverage across
the mountains and deserts after midnight through Saturday morning.
Snow levels will be near 6500 ft. Shower activity will decrease
by mid-Saturday morning, with dry conditions expected to return
by Sunday. Periods of gusty northeast to east winds will continue
overnight into Saturday. A gradual warming is expected for next
week, with high temperatures returning to above normal by the
middle of the week. A weak Santa Ana is possible sometime mid-
week.

&&

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

Current radar at 9 PM was showing a swath of precipitation just
south of the border, with an isolated light shower or two moving
across San Diego County. The forecast is still on track for wrap
around moisture from an upper level low moving into northern Baja
tonight. High resolution guidance has most of the shower activity
developing for the mountains and deserts after midnight. Rain and
snow shower activity is expected to become more isolated by mid-
Saturday morning. Light showers may continue into Saturday afternoon
as the low slowly moves east. Dry conditions are expected to return
by Sunday.

Northeast to easterly winds have developed on the coastal mountain
slopes and locally into the valleys. Peak gusts as of 9 PM have
mainly been in the 35 to 45 mph range, with a few isolated gusts to
50 mph in wind prone locations. These winds will continue into
Saturday, slowly weakening and becoming more isolated into Sunday.

From previous discussion issued 2 PM November 21...

The upper low over the California Bight will be pulled southward
into northern Baja tonight into Saturday. As this occurs, wrap
around precipitation is set to fill back into the area this evening
into the overnight hours, favoring the deserts and southern/eastern
mountain slopes, especially in San Diego County. This precipitation
will generally be light, with rates up to 0.1-0.2"/hr though
localized enhancements, particularly along the San Diego County
desert mountain slopes, are possible. Additional rainfall totals
from this wrap around will be 0.2" or less for the coasts/valleys,
0.75-1" in the mountains (though eastern slopes could see additional
totals closer to 1.5-1.75"), and 0.25-0.5" in the deserts. Snow
levels remain near 6500ft through tonight but gradually rise to
~7000ft Saturday afternoon. Additional snowfall above 6500ft through
Saturday morning range from 2-5", with locally up to 9" on eastern
mountain slopes. Snowfall rates could be 1-1.5"/hr at times and
given the expected additional snowfall, the Winter Storm Warning has
been extended through 10 AM Saturday for mountain elevations in San
Bernardino County and Riverside County greater than 6500ft.

The wrap around precipitation eventually tapers off by Saturday
afternoon as the upper low begins to lift northeastward and dry
northwesterly flow aloft returns for Sunday into Monday.
Temperatures slowly respond with a subtle warming trend that returns
afternoon highs to seasonable norms by Monday/Tuesday. Ensembles are
consistent with a trough digging from the Pacific Northwest through
the Great Basin, aiding to strengthen to the offshore pressure
gradient Tuesday into Wednesday. Currently there is about a 40%
chance of a weak to moderate Santa Ana event mid-next week, likely
peaking around Wednesday. Between the offshore winds and an upper
ridge peaking Thursday, temperatures warm to 5-10 degrees above
normal for Wednesday into Thursday.

Looking into the far extended, ensembles continue to hint on another
storm system late next week that could bring another round of rain.
Significant uncertainty remains in the timing and track of this next
trough, so it`s not something to get too excited about just yet.

&&

.AVIATION...
220400Z...Coasts/Valleys...Light rain and associated cig/vis have
become more isolated with sct/few clouds between 5,000 to 7,000 ft
MSL. Light rain will increase in coverage again mainly over San
Diego County this evening through 12Z Saturday. East to northeast
winds gusting 25-35 knots in the coastal foothills and locally into
inland valleys through 00z Sunday.

Deserts/Mtns...BKN-OVC low clouds 5000-8000 ft MSL currently. SHRA
will become more persistent and widespread in the low deserts after
09z with MVFR cig/vis reductions at times. SCT FG/SHRA/SN in the
mtns through Saturday morning, especially along the eastern slopes,
where precip will be favored. Conditions slowly improving after 18Z
everywhere with any precip becoming more SCT and intermittent.

&&

.MARINE...
No hazardous marine conditions are expected through Wednesday.

&&

.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 10 AM PST Saturday for Riverside
     County Mountains-San Bernardino County Mountains.

PZ...None.

&&

$$

PUBLIC...CO/Munyan
AVIATION/MARINE...Villafane