684
FXUS66 KSGX 182201
AFDSGX

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

.SYNOPSIS...
Widely scattered, mostly light showers will continue today into
this evening with the next Pacific low pressure system from the
northwest bringing another round of more widespread showers for
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...

Today through Wednesday...

Current satellite and mesoscale analysis depicts the upper level
low pressure system responsible for the continued unsettled
weather positioned near Point Conception. While this system will
be relatively progressive in its departure for a cut-off low, the
core of the low is set to pass overhead Wednesday afternoon and
depart Wednesday night. Until then, isolated to scattered showers
remain possible. The focus for shower activity today will
generally be for the coastal basin from the waters through the
coastal slopes of the mountains, while Wednesday`s shower activity
should be limited to the mountains. Rainfall rates from any of
these showers will be largely light, with additional accumulations
of less than a quarter of an inch through Wednesday evening. With
the passage of the cold core upper low, snow levels stay low
through Wednesday evening, near 5500-6000ft, with any shower
activity above these elevations falling as snow. Additional
snowfall accumulations through Wednesday are about an inch or
less, with locally higher totals on the highest mountain peaks.
Temperatures stay notably below average as this system passes
through, with afternoon high temperatures 10 to 15 degrees below
normal and low temperatures dipping into the 40s for inland
valleys.

Thursday through Saturday...

Attention then quickly turns to the next weather system in the form
of yet another cut-off low that is currently progged to drop
southward from northern California on Thursday into Friday. As with
most cut-off lows, 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 cut-
off 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
today/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 offshore 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... 182100Z...Widely scattered showers expected through
07z Wednesday with scattered snow in the higher mountains.
Precipitation will generally be light in nature. Slight chances for
precipitation will return after 20Z Wednesday for over the
mountains. BKN cloud deck is expected to stay between 5,000 to
10,000 ft MSL for most of the period with areas along the coast
dipping down to 3,500 ft MSL around 01-02Z before lifting/scattering
around 07Z.

&&

.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.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Weather Advisory until 10 PM PST this evening for San
     Bernardino County Mountains.

PZ...None.

&&

$$

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