077
FXUS66 KSGX 161745
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
945 AM PST Sun Nov 16 2025

.SYNOPSIS...
Scattered showers will continue today, becoming less widespread
and weaker in the afternoon. A weaker storm will move through the
area Monday afternoon into Wednesday morning, bringing another
chance of rain showers and mountain snow. An additional storm
system will approach the region by next Thursday and Friday, but
forecast details remain uncertain.

&&

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

.Morning Update...

Light showers will continue along the coastal slopes to the coast
through the afternoon hours. Some cells may produce rain rates
near 0.50"/hr at times according to latest hi-res model guidance.
We continue to watch the next weather system, which has shifted
slightly later in time with the passage of the heaviest showers
pushing from west to east by Monday afternoon and evening with
hourly rain rates over 0.50"/hr. Accumulating snowfall above 5,000
is still expected with areas near Big Bear to see around 2-4
inches through Tuesday. The forecast for the end of the week still
remains largely uncertain.

.Previous Discussion (259 AM Sunday)...

Scattered showers continue across the region this morning. For the
most part rainfall rates are below 0.15"/hr, but isolated heavier
showers have been producing rates closer to 0.30-0.50"/hr. Expect
this activity to continue through early this afternoon, then
becoming more isolated and weaker for the remainder of the
afternoon into tonight. Latest hi-res models aren`t showing much
of a break in these isolated showers before the next system moves
in, but given how isolated they are, most places should have at
least a several hour break in precipitation. Additional
precipitation through Monday morning will range from around
0.10-0.50" for the coasts/valleys, 0.20-0.80" in the mountains,
and 0.10" or less in the deserts. Snow levels will fall to around
6500 ft this morning, though less than an inch of snow is expected
at those elevations. Snow levels rise back to around 7000 ft
during the afternoon. Otherwise chilly today with high
temperatures around 10-20 degrees below normal and breezy
southwest to west winds in the mountains and deserts.

While ensembles are in generally good agreement with the
progression of the next closed upper low, small deviations in the
track are resulting in continued spread in rainfall amounts. The
NBM 48 hr totals (4 AM Mon-4 AM Wed) still has a difference of
around 0.6-0.8 inch between the 25th percentile and 75th
percentile. Mean totals for this 48 hour period are around 0.60-1"
for the coasts and valleys, and around 1-1.25" in the mountains,
though it is notoriously underdone for orographic precipitation.
Current forecast is close to the NBM mean, though with amounts
closer to 1.5-1.8" along the coastal mountain slopes. Totals in
the high desert are around 0.15-0.40", and around 0.10-0.30" in
the low deserts. This storm will have far less moisture associated
with it (PW peaking around 1" and IVT near 250 kg/m/s), so
rainfall rates will be lower, reducing the threat of flash floods
and debris flows. Street flooding will be an issue once again.
Precipitation will taper off through the day Wednesday. Snow
levels will be much lower with this storm, falling as low as
5000-5500 ft Tuesday morning and only rising slightly to 5500-6000
ft during the day. Around 1-2" of snow is possible at the
6000-6500 ft level, 2-4" at 6500-7500 ft level, and as much as
10-12" on the highest peaks of the San Bernardino Mountains (above
9000 ft).

Another brief dry period occurs Wednesday evening through
Thursday morning. Ensemble solutions for the next closed low late
in the week vary wildly. Around 22% of the members track the low
too far north and east to bring any precipitation here, another
23% swing the low way off the coast, delaying the onset of
precipitation until later Friday into Saturday, and the remainder
falling somewhere in between. The current resultant range in storm
totals is anywhere from 0 to almost an inch. The track of the low
will also have implications on snow levels. Will have to wait and
see how the details shake out, but there is at least a 40% chance
for precipitation sometime late in the week.

&&

.AVIATION...
161700Z...Primarily VFR conditions through the period with SCT-BKN
low clouds through the coastal basin around 3-5 kft. Scattered
-SHRA/SHRA currently moving over the coastal basin and mountains
from the southwest to northeast. Occasional MVFR cigs/vis in SHRA.

&&

.MARINE...
Scattered showers over the waters through this afternoon. Northwest
winds strengthen again Monday afternoon ahead of the next storm
system bringing gusts to 20-25 knots through Tuesday morning, along
with another round of precipitation.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

UPDATE...APR
PUBLIC...SS
AVIATION/MARINE...KW