DesertWeather.com

174
FXUS66 KSGX 110534
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1034 PM PDT Thu Sep 10 2026

.SYNOPSIS...
The hot and humid high pressure system over the desert southwest
will continue to weaken into the weekend. Hot conditions this
afternoon will bring a cooling trend with lower humidity over the
next few days as an area of low pressure is expected to move
through the West Coast by the weekend. Monsoonal moisture hangs on
for one more day this afternoon with a slight chance of
thunderstorms across the mountains and adjacent deserts. The weak
troughing pattern will stick around into at least the first half
of next week, bringing a deeper marine layer and cooler weather.

&&

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

...UPDATED AVIATION DISCUSSION...

A troughing pattern begins to develop over the West Coast by
Friday, which will help weaken the high pressure system further
and bring in more cooling. High temperatures were raised slightly
from the previous forecast, but still shows a steeper decline in
temperatures mainly west of the mountains from 5-10 degrees cooler
than today. A stronger low pressure system develops from this
troughing pattern to the north, swinging through the Pacific
Northwest this weekend. This will bring further cooling to our
region with temperatures lowering closer to normal for the middle
of September. Welcome highs in the 80s/90s for western valleys,
most mountain areas, and locales in the high desert can be
expected. Overnight temperatures and humid conditions will also
decrease into the weekend as well as drier southwest flow moves
into our area. Morning temperatures in the 70s will be replaced
with 60s west of the mountains making it feel much more
comfortable for us. The marine layer will also slowly return for
coastal and western valley areas over the next few days as well.

The area of low pressure moves out of the Pacific Northwest by
Monday, leaving behind a weak troughing pattern over the region
for at least the first half of next week. This will bring similar
temperatures each day with highs and lows near to slightly below
average with dry weather.

&&

.AVIATION...
110530Z...Coast...Patchy low clouds and fog will gradually develop
overnight with bases around 600-900 feet MSL and vis 1-5SM, lowest
on coastal mesas. Cigs most likely 10-16Z, and around KSAN. Low
clouds to return after 02Z Friday eve with more uniform and
expansive coverage. Bases around 900-1200 feet MSL.

Otherwise, SCT clouds above 15 kft and VFR conditions through Friday
with cumulus clouds around 10 kft over mountains 19-00Z.

&&

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

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning until 8 PM PDT Friday for Coachella Valley-
     San Diego County Deserts-San Gorgonio Pass near Banning.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...MM