Tustin, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

739
FXUS66 KSGX 262017
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
117 PM PDT Wed Aug 26 2026

.SYNOPSIS...
Persistent high pressure will continue hot days and near-record
warm nights through Friday night, with a slight chance of showers
and thunderstorms for the mountains this afternoon and Friday
afternoon. High pressure will weaken for the weekend into early
next week with high temperatures cooling to around average next
Monday. 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...

This afternoon...Mid and high clouds moving into San Diego County
from the south could produce isolated light showers and possibly
a tstm or two over the next several hours, mainly in the mountains
but a few light showers could develop over the valleys and coastal
areas. Temperatures are mostly a few degrees higher than at this
time yesterday.

Through friday...High pressure will continue to bring hot weather to
Socal. 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. High temperatures will
range from the 80s near the coast to 100 to 108 for the Inland
Empire with 112 to 116 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
likely not tie or exceed existing records, many records for
warmest overnight low temperatures could be tied or broken, most
likely on Thursday and Friday.

A cooling trend is expected for Saturday into the middle of next
week as high pressure aloft weakens and shifts to the southeast in
response to a developing trough of low pressure near the
California coast which will strengthen lower-level flow onshore.
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...
Through Friday...low humidity and locally gusty westerly winds
could produce elevated fire weather conditions during the
afternoon hours in areas above 2,000 ft, especially in and below
mountain passes and canyons. Persistent high pressure will
continue hot days and near-record warm nights through Friday
night, with a slight chance of showers and thunderstorms for the
mountains this afternoon and Friday afternoon. High pressure will
weaken for the weekend into early next week with high temperatures
lowering to around average next Monday. Dry conditions with
stronger onshore flow will produce elevated fire weather
conditions, mainly in the mountain passes and canyons.

&&

.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...PG
AVIATION/MARINE...KW