256
FXUS66 KSGX 082049
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
149 PM PDT Fri Aug 8 2025

.SYNOPSIS...
Hot conditions expected continue into early next week with
widespread moderate HeatRisk across the Inland Empire, mountains,
and High Desert with widespread major HeatRisk in the low desert.
Conditions will gradually cool to near or slightly below normal by
the end of next week. The marine layer will deepen slightly and
become more widespread across the coast and western valleys tonight
into Saturday. The marine layer is expected to deepen further later
next week.

&&

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

Temperatures at 1 PM were running anywhere from 3 to 12 degrees
cooler than yesterday, with some mountain locations a degree or two
warmer. Overall, temperatures hit their peak yesterday and although
hot conditions will be maintained into early next week for inland
locations, it`s unlikely conditions will be as hot as they were on
Thursday. Ensemble guidance is indicating an increase in
precipitable water for the lower deserts on Saturday, which would
result in a lower high temperature reading. That will quickly be
followed by a decrease in precipitable water for early next week.
Chances of exceeding 110 degrees on Saturday in the low desert are
80 to 90 percent, with chances increasing to 95 to 100 percent for
Sunday through Tuesday. Chances of exceeding 115 degrees are 30 to
40 percent Sunday through Tuesday and under 15 percent for Saturday.
Current forecast has high temperatures 110 to 115 degrees into early
next week and maintains fairly widespread major HeatRisk.

The marine layer will deepen slightly over the weekend and become
more uniform in coverage. That should help moderate temperatures for
the coast, inland Orange County, and San Diego valleys. The marine
layer is not expected to deepen enough to reach into the Inland
Empire, maintaining areas of moderate HeatRisk through the weekend.
High pressure aloft combined with a shallow marine layer will
maintain hot conditions in the mountains. Highs there will be in the
80s to 90s with widespread moderate HeatRisk. If you`re planning to
be outside over the weekend in the Inland Empire, mountains, or
deserts make sure you stay hydrated and seek plenty of shade if
you`re doing recreational activities.

Gradual cooling trend will prevail next week. By Tuesday, high
temperatures will be near normal west of the mountains and 5 to 8
degrees above average in the deserts. High temperatures on Thursday
will be a few to around 5 degrees below average for the coast and
valleys and a few degrees above average for the deserts. Widespread
near to below average temperatures are expected by Friday. Night and
morning coastal low clouds will spread into the far western valleys
late each night.

&&

.AVIATION...
082030Z....Coasts...Satellite shows low clouds are hanging right at
the beaches, and coastal airports are expected to remain VFR through
early evening. Low clouds move back inland around 03z with slightly
higher bases than this morning, around 600-1000ft MSL. More uniform
coverage tonight and low clouds will push up to 10 miles inland
through 12z. VIS reductions remaining likely along coastal terrain
and in some valleys. Clouds clear to the coast at a similar time as
today, around 17z Sat.

.Valleys/Mountains/Deserts...Hazy but VFR through tomorrow. Gusty
surface winds up to 25kts out of the west/southwest expected 23z Fri-
03z Sat in the deserts and desert slopes. Lighter winds prevail
after 03z.

Smoke from area fires, mostly the Gifford Fire in Santa Barbara
County, will continue to be present at or above 10,000 feet MSL.
Surface conditions hazy but still VFR.

&&

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

&&

.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 Monday for Riverside County
     Mountains-San Bernardino County Mountains-San Bernardino
     and Riverside County Valleys-The Inland Empire-San Diego
     County Mountains.

     Heat Advisory until 8 PM PDT this evening for Orange County
     Inland Areas-San Diego County Valleys-Santa Ana Mountains
     and Foothills.

     Extreme Heat Warning until 8 PM PDT Tuesday for Coachella Valley-
     San Diego County Deserts-San Gorgonio Pass near Banning.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE...Zuber