652
FXUS66 KSGX 190523
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
923 PM PST Tue Nov 18 2025

.SYNOPSIS...
Widely scattered, mostly light showers will continue tonight with
the potential for additional light wrap around showers into
Wednesday afternoon. Another round of scattered light showers
develop on Thursday ahead of the next Pacific low pressure system,
which will bring another round of more widespread showers
Thursday night and Friday with decreasing chances for showers into
the weekend. Drier and warmer for next week.

&&

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

Evening update...
Widely scattered light showers continue this evening, mainly
across San Diego County. Rainfall rates with these showers will be
less than 0.10"/hr. The center of the upper level low is
currently over the CA bight and is forecast to move inland across
So Cal through Wednesday afternoon. With residual moisture still
in place and cold air aloft, additional light showers could
develop over the mountains again Wednesday afternoon (15-30%
chance). Depending on how the low tracks, wrap around showers
could move in from the north during the day Wednesday as well,
though confidence in where this showers will track is low. There
is around a 10-20% chance of additional rain accumulations of
0.10" or more through 10 PM Wednesday, as high as a 30-40% chance
in the mountains, and a 15-20% chance of 0.25" or more in the
mountains. Snow levels remain near 5000-5500 ft tonight,
increasing to near 6000 ft Wednesday afternoon as the low moves
east. Additional snowfall below 7000 ft will generally be less
than 1", locally around 1-2" above 7000 ft should wrap around
showers materialize in those areas. Otherwise cool on Wednesday
with high temperatures around 5-10 degrees normal near the coast
and 10-15 degrees below normal elsewhere.

Previous discussion...

Thursday through Saturday...

Attention then quickly turns to the next weather system in the form
of yet another closed low that is currently progged to drop
southward from northern California on Thursday into Friday. As
with most closed lows digging south, volatility in their forecast
track/timing and uncertainty is quite high, though ensemble
guidance is coalescing towards a scenario where the center of this
low drops considerably far south, over northern Baja by Saturday
morning. The effect of a low tracking as such brings a cold front
through the region some time early on Friday. High resolution
guidance now in range suggests the chance for light pre-frontal
showers on Thursday, primarily for the coastal areas. The main
band of precipitation will accompany the cold front overnight
Thursday into Friday though several ensemble members are depicting
the potential for wrap around precipitation on the northern side
of the low. Given the inherent uncertainty in the track of the
closed low, a fairly wide spread in the forecast total rainfall
remains for this event. The most likely outcome is to see 0.75-1
inch on the coasts/valleys, with 1-1.5 inches in the mountains,
however, should the intensity of the wrap around banding come to
fruition as seen a higher-end clustering of ensemble members,
localized rainfall totals off the mountains could be closer to
1.5-2 inches. Given the displacement of the center of the low to
the south, snow levels will be a touch higher than seen
tonight/tomorrow, closer to 6500-7000ft.

In addition to the precipitation, wind will also be a notable impact
from this second system. Initially, elevated southerly winds ahead
of the cold front could bring wind gusts of 20-25 mph to the coasts
and coastal waters Friday morning. Then, depending on the track of
the upper level low, easterly winds on the north side of the parent
storm system could bring easterly winds to the region Friday
afternoon, brining strong wind gusts to mountains, mountain
passes, the high deserts, and portions of the Inland Empire.

Early next week...

The late week storm system eventually slides eastward into
Arizona/New Mexico on Sunday, though uncertainty in the upper level
pattern increases dramatically come early next week. Zonal flow to a
weak ridging looks to be the dominant solution, though the
timing/intensity of the ridge is in question. Ultimately,
temperatures will gradually warm back to near normal for
Sunday/Monday. Conditions look to stay dry as well, bringing an end
to the wet pattern we`ve been in as of late.

&&

.AVIATION...
190430Z...Areas of SCT-BKN clouds generally 4-8 kft MSL and isolated
SHRA, mainly around eastern SD county.

Slight (20-30%) for additional ISO SHRA to develop overnight through
15z, with highest chances over the waters and SD County. Remaining
clouds gradually scatter out for most places early Wednesday
morning. After 18z Wed, cumulus clouds develop over mountains and
deserts, with a 25-35% chance for patchy SHRA over these areas
Wednesday afternoon. Additionally, FEW-SCT clouds based 2-7 kft MSL
develop over the region after 00z Thurs.

VFR conditions prevail through the period, with exception of areas
with elevated terrain intersecting clouds and locally near SHRA,
where VIS reductions and MVFR cigs are possible.

&&

.MARINE...
No hazardous marine conditions are expected through Thursday, but
the next storm system has the potential to bring hazardous winds and
seas Thursday night and Friday.

&&

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


&&

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

PZ...None.

&&

$$

PUBLIC...SS/DM
AVIATION/MARINE...Westerink

NWS San Diego (SGX) Office