693
FXUS66 KSGX 290403
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
903 PM PDT Thu Aug 28 2025

.SYNOPSIS...
Showers ending this evening as remnant tropical moisture moves off
to the east. Warmer and drier Friday through the weekend.
Monsoonal moisture will increase again by early next week, with
chances for showers and thunderstorms over the mountains and
deserts each afternoon beginning on Monday. Otherwise warm
with highs up to 5 degrees above normal through the week.

&&

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

Tropical moisture from Tropical Storm Juliette brought widespread
rain across San Diego County and parts of Riverside and San
Bernardino Counties today, but is now pushing east and out of our
forecast area this evening. The southern San Diego County
mountains were the big winners with 0.76" and 0.74" at Mt Laguna
and Cameron, respectively, with decreasing amounts to the north
and west. A full list of rainfall measurements is on our home
page. Only deviation from the previous forecast is that Friday has
trended drier with minimal chances of a stray shower over the
mountains in the afternoon.

Previous discussion...
A warmer and slightly less humid weather will occur on Friday
with mostly sunny skies. There will be drying, but a weak amount
of monsoonal moisture will be available to warrant a slight chance
for a shower or weak thunderstorm to form over the mountains. The
atmosphere continues to dry out over the weekend with PWAT values
lowering under one inch across the lower deserts by the weekend.
This will diminish any notable chances for storm activity by the
weekend with all other areas seeing mostly sunny skies. A warming
trend will also occur for areas away from the coast during this
time. Highs will be near to slightly above average by Sunday.

Monsoonal moisture will increase again by Labor Day into the middle
of next week, which will lead to a greater chance of shower and
thunderstorms across the mountains and deserts. By Tuesday through
Thursday, chances will be around 20-30% across these areas. A weak
trough offshore may start to form sometime in the middle of next
week, which would lower the chances for any storms to occur. Other
areas will remain quiet with near to slightly above normal
temperatures.

&&

.AVIATION...
290300Z...SCT-BKN clouds AOA 10000 ft MSL will slowly exit the
region through Friday morning. A few patches of coastal low clouds
VCNTY coastal TAF sites with bases around 1000 feet MSL. Chance of
CIG impacts (less than 30 percent) through 08Z Friday. Cumulus based
10000 ft MSL over ridgetops 18Z Fri to 01Z Sat along with a slight
chance -SHRA.

&&

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

&&

.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/APR
AVIATION/MARINE...KW