DesertWeather.com

660
FXUS66 KSGX 222032
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
132 PM PDT Mon Sep 22 2025

.SYNOPSIS...
Clouds and showers will decrease in coverage from northwest to
southeast overnight into Tuesday morning and out of the area by
Tuesday afternoon. Precipitation chances decrease for tonight
into Tuesday but could return for Tuesday afternoon into early
Wednesday, along with a slight chance of thunderstorms mainly for
areas north of San Diego County. Drier weather returns for
Thursday into Friday, but then slight chances of precipitation in
the mountains for Friday and Saturday afternoons. By Sunday, the
disturbance will begin to move east and out of the region, with
slight warming and drying conditions going into the early part of
next week. Temperatures will overall remain near, or slightly
below, the seasonal average with decreasing coastal low clouds
throughout the week.

&&

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

This afternoon, clouds and showers are decreasing from northwest
to southeast as the upper low to our southwest remains nearly
stationary. A few light showers could impact southern San Diego
County through tonight but any additional rainfall will be light
and should be out of the region by late Tuesday morning. The
marine layer will remain shallow at least through Tuesday, with
low clouds and fog mostly restricted to the coastal areas and
western portions of the inland valleys. Temperatures today will be
near or a little below seasonal averages.

From previous discussion...
This upper low will control our weather through the forecast
period. Numerical models are in good agreement through Wednesday
with respect to the timing and position of the upper low so
forecast confidence is fairly high. We can expect the low to
drift a little farther south through tonight before beginning to
move northeast, becoming centered northwest of Point Conception by
Wed afternoon. Tuesday and Wednesday will be mostly dry, although
there is a chance for some showers and possibly tstms on Wed in
the extreme southwest corner of San Bernardino County and the
northwest corner of Riverside County as the low begins to move
south and east. Wed into Thu could also be a little windy in the
mtns and deserts as onshore flow strengthens due to the position
of the low. Wind gusts of 35 to 40 knots are likely in favored
locations. Temperatures rise on Tuesday becoming mostly a few
degrees above seasonal averages as we lose some of the cloud cover
that has been inhibiting the warming.

After Wednesday, more uncertainty creeps into the forecast with
model solutions diverging as the low moves to the south and east.
The consensus model solution keeps conditions dry on Thu but about
20% of ensemble members indicate chances for afternoon
showers/tstms in the mtns and deserts Friday and Saturday. Sunday
and Monday will likely be dry as the low moves to the southeast
and we lose access to moisture. For Wed through next weekend,
daytime temperatures will be mostly below seasonal averages except
for some areas on Wednesday.

&&

.AVIATION...
222000Z....Coast/Valleys...Patchy and intermittent low clouds and
fog will start to redevelop after 03Z tonight into Tuesday with vis
dropping to 3-6SM and cigs around 600-800 feet MSL reaching up to 3
miles inland. Tempo grps added for KSAN and KCRQ for cigs dropping
into LIFR around 11-12z. Clouds should clear to the coast by 15z.

Mountains/Deserts...Expect briefly lowered bases and vis with
isolated SHRA/TSRA in the afternoon/evening over eastern San Diego
County mainly over/near the mountains through 00z. Everywhere else,
SCT cigs around 10000 feet MSL are expected through through the TAF
period.

&&

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

&&

.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...PG
AVIATION/MARINE...Villafane