634
FXUS66 KSGX 301844
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1144 AM PDT Thu Jul 30 2026

.SYNOPSIS...
The marine layer will stay thin through the upcoming weekend,
where night and morning low clouds will cover the coast each day.
High pressure will strengthen across the region through the
weekend as well, where areas of mostly moderate to major heat
risk will occur across much of Southern California. Slight cooling
with an increase in monsoonal moisture will lead to continued
humidity, but a limited chance of rainfall in the mountains and
deserts.

&&

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

The marine layer was not as deep this morning as high pressure
over the Desert Southwest begins to squash the layer. Low clouds
will continue to cover areas mainly within 10 miles of the coast
each night and morning through the weekend. Slightly warmer
conditions will be felt today as the high over New Mexico slowly
expands. 850mb temps rise more significantly by Friday, so
temperatures will warm another 3-5 degrees for most areas. This
will bring temperatures near 105 degrees from the Inland Empire
into the metropolis of the High Desert, as well as highs in
80s/90s for coastal valleys and mountains.

For the weekend, the area of high pressure peaks in strength on
Saturday. This is when we can expect the hottest temperatures.
Temperatures will be well into the 90s for valleys and mountains
of Orange and San Diego Counties and over 115 degrees across the
lower deserts. The high weakens slightly on Sunday, but
temperatures only knock down a degree or two. All mountains will
remain hot as well. Please severely limit or postpone outdoor
recreation in these areas, since temperatures will be well into
the 70s and 80s by the mid-morning hours. For those without A/C,
make sure to go to air conditioned areas and drink plenty of
water. Warm and humid nights in the 60s/70s/80s will lead to less
relief from the heat as well.

By early next week, the high weakens subtly and shifts back to the
east. This will bring a degree or two of cooling for inland areas
each day, but warm temperatures will still remain. Temperatures
will stay near to slightly above normal by Wednesday of next week.
The high may go into a position that will bring in a subtle
return of monsoonal moisture and greater humidity to the region,
but rain chances still seem slim.

&&

.AVIATION...
301800Z....Coast/Valleys...Low clouds based around 800-1200 feet MSL
will develop and move locally inland again after 01Z. They will not
reach as far inland as they were this morning. Vis restrictions 0-
5SM in western valleys. Scatter out Friday by 15-16Z.

Mountains/Deserts...Mostly clear through Friday morning.

&&

.MARINE...
No hazardous marine weather is expected through Monday.

&&

.BEACHES...
A southerly swell from Hurricane Genevieve will continue to generate
elevated surf through Friday before diminishing over the weekend.
Surf of 4-7 feet with sets up to 9 feet will continue, highest on
south facing beaches. This will create conditions hazardous for
inexperienced swimmers. In addition, high tides each evening will
exceed 6 feet. The combination of high tides and high surf increases
the risk of coastal flooding. Further information on all these
hazards is found in the Coastal Hazard Message.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 AM PDT Saturday for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     High Surf Advisory until 5 PM PDT Saturday for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     Heat Advisory from 10 AM Friday to 8 PM PDT Sunday for Orange
     County Coastal Areas-San Diego County Coastal Areas.

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

     Extreme Heat Warning from 10 AM Friday to 8 PM PDT Sunday for
     Orange County Inland Areas-San Diego County Valleys-Santa
     Ana Mountains and Foothills.

     Heat Advisory until 8 PM PDT Sunday for San Bernardino County
     Mountains.

PZ...None.

&&

$$

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