Tustin, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

459
FXUS66 KSGX 261802
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1102 AM PDT Wed Aug 26 2026

.SYNOPSIS...
Near-record high pressure for late August will continue hot days
and near-record warm nights through Friday night with a slight
chance of showers and thunderstorms for the mountains for this
afternoon and Friday afternoon. High pressure will weaken for the
weekend into early next week with high temperatures cooling to
around average on Monday of next week. For Tuesday and Wednesday
of next week, there is a 10 to 20 percent chance for an increase
in clouds and a chance of precipitation from a tropical system
that has yet to develop.

&&

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

...UPDATED AVIATION DISCUSSION...

.SHORT TERM (Today through Friday)...
High temperatures will be around 10 degrees above average with low
temperatures as much as 15 to 20 degrees above average for the
lower elevations of the mountains. Through Friday, high
temperatures will range from the 80s near the coast to 100 to 110
for the Inland Empire with 112 to 118 for the lower deserts. Low
temperatures will be mostly in the 70s for the coast, valleys, and
high desert and in the mid 80s to mid 90s for the lower deserts.
Low temperatures will be around 80 for the lower elevations of the
mountains. The highest HeatRisk is expected on Thursday with
widespread Moderate to Extreme HeatRisk for the valleys, inland
coastal areas, and lower deserts.

While the high temperatures will mostly not tie or exceed existing
high temperature records, many records for warmest overnight low
temperatures will likely be tied or broken with the greatest
number on Thursday and Friday.

Swell from Tropical Storm Iselle and former Tropical Storm Julio
will bring elevated surf of 4 to 6 feet to the beaches for today
through Thursday evening.

There may be enough residual monsoonal moisture for a few showers
or thunderstorms for the mountains for this afternoon with
additional drying for Thursday.

&&

.LONG TERM (Saturday through Tuesday)...
A cooling trend is expected for Saturday into the middle of next
week as high pressure aloft weakens and a developing weak trough
of low pressure near the California coast strengthens onshore
lower-level flow. High temperatures will cool to around average
for next Monday with low temperatures cooling to slightly above
average.

There could be some increase in clouds and a chance of
precipitation around Tuesday or Wednesday of next week from
moisture from a tropical system that has yet to develop.

&&

.AVIATION...
261800Z...Coast...VFR conditions prevail through early Thursday
morning. Very patchy low clouds based 200-600 ft MSL develop over
nearshore waters after 09z Thu, intermittently pushing ashore into
coastal areas mainly in San Diego County. Vis reductions of 1SM or
less possible where low clouds/FG develop. Greatest chances for
cigs/vis reductions at coastal TAF sites will be from 12-15z (20% at
KCRQ, 50% at KSAN). Any low clouds scatter out by 16z.

Mountains/Deserts...Cumulus based around 9000 feet MSL with ISO TSRA
and CB tops to 40000 feet MSL over mountains into adjacent deserts
20-01Z. Any TS that develops could produce gusty, erratic winds.

Regionwide...FEW high clouds AOA 15000 feet MSL gradually becoming
SCT-BKN this evening and tonight.

&&

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

&&

.BEACHES...
A 4-5 ft southerly swell (from 170 degrees) at 12-13 seconds will
continue to produce elevated surf through Thursday, particularly for
south-facing beaches of northern San Diego County and Orange County.
Surf of 3 to 6 feet, with sets up to 7 feet are expected. Check the
Coastal Hazard Message for details on Beach Hazards.

&&

.FIRE WEATHER...


&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Friday for Orange County Coastal
     Areas-Riverside County Mountains-San Bernardino County
     Mountains-San Diego County Coastal Areas.

     Beach Hazards Statement through Thursday evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.

     Extreme Heat Warning until 8 PM PDT Friday for Apple and Lucerne
     Valleys-Coachella Valley-Orange County Inland Areas-San
     Bernardino and Riverside County Valleys-The Inland Empire-
     San Diego County Deserts-San Diego County Mountains-San
     Diego County Valleys-San Gorgonio Pass near Banning-Santa
     Ana Mountains and Foothills.

PZ...None.

&&

$$

PUBLIC/FIRE WEATHER...Martin
AVIATION/MARINE...KW