724
FXUS66 KSGX 271024
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
324 AM PDT Wed Aug 27 2025

.SYNOPSIS...
Monsoonal moisture will continue to decrease today with decreasing
coverage of thunderstorms for this afternoon with the most likely
locations along the desert slopes of the mountains in Riverside
and San Diego Counties into the adjacent deserts. For late tonight
and Thursday into Thursday evening, there will be increasing
moisture from the remnants of Tropical Storm Juliette with
scattered showers spreading northeastward across portions of
southwestern California along with a slight chance of
thunderstorms. Warming and drying is expected for Friday through
the weekend. The moisture will slowly return next week with a
slight chance of afternoon and early evening thunderstorms for
the mountains and deserts.

&&

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

.SHORT TERM (Today through Friday)...
Drying of monsoonal moisture will continue today with fewer
afternoon thunderstorms, mostly along the desert slopes of the
mountains of Riverside and San Diego Counties into the adjacent
deserts.

For late tonight and Thursday into Thursday evening, there will be
increasing moisture from the remnants of Tropical Storm Juliette
with scattered showers spreading northeastward across portions of
southwestern California. The most likely locations for
thunderstorms with heavier rainfall on Thursday should be toward
the northern edge of the moisture where cloud cover is less and
daytime heating greater. Thunderstorms with locally heavy rainfall
and isolated flash flooding are most likely on Thursday over the
Riverside County mountains and San Bernardino Mountains.

With the greater cloud cover, Thursday will be cooler as well with
high temperatures as much as 10 to locally 15 degrees below
average for the lower deserts and adjacent mountains. High
temperatures on Thursday will range from the mid to upper 70s near
the coast to the mid 80s to lower 90s for the Inland Empire and
mostly in the 90s for the lower deserts.

Warming and drying will begin on Friday and continue into the
weekend. Friday high temperatures will be a few degrees warmer
than Thursday to as much as 4 to 8 degrees warmer for the
mountains and deserts of San Diego and Riverside Counties. High
temperatures on Friday will range from the mid 70s to lower 80s
near the coast to the upper 80s to mid 90s for the Inland Empire
with 100 to 105 for the lower deserts. A slight chance of
thunderstorms will remain for Friday afternoon, mostly for the
mountains.

&&

.LONG TERM (Saturday through Tuesday)...
The drying will continue into the weekend and the warming through
the weekend. Monsoonal moisture may begin to gradually return for
Sunday into early next week with slowly increasing chances for
afternoon and early evening thunderstorms, mostly for the
mountains and deserts. High temperatures will slowly cool for
early next week as the moisture increases.

&&

.AVIATION...
270930Z...Coast...Patchy low clouds at around 1200 feet MSL will
increase a little through sunrise, but uniform areal coverage is not
expected. Any cigs will clear by 16Z. Only the most patchy low cloud
situation is expected tonight into Thursday, with bases 800-1000
feet MSL.

Valleys/Mountains/Deserts...Isolated SHRA/TSRA 19-01Z with CB bases
around 10000 feet MSL, mostly confined to the mountains with lower
chances in the low desert and eastern high desert. TSRA could
produce gusty and erratic winds of 30 kts, periods of lower vis 2-
5SM in +RA, and lightning.

Regionwide...SCT clouds at or above 12000 feet MSL today, increasing
tonight.

&&

.MARINE...
There is a slight chance of thunderstorms Thursday. Any thunderstorm
could produce gusty, erratic winds leading to locally rough seas,
along with lightning and hail. Otherwise, no hazardous marine
conditions are expected through Sunday.

&&

.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...17
AVIATION/MARINE...MM

NWS Tucson (SGX) Office