610
FXUS66 KSGX 050812
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
112 AM PDT Wed Aug 5 2026

.SYNOPSIS...
There will be a gradual warming trend through Saturday with slowly
increasing HeatRisk. On Saturday, there will be moderate HeatRisk
for the mountains and Inland Empire with major to locally extreme
HeatRisk for the deserts. Night and morning low clouds will
continue to spread into coastal areas and occasionally the far
western valleys late each night. There will be slowly increasing
monsoonal moisture in east to southeast flow aloft into early next
week with a few showers over the mountains on Thursday afternoon
and a slight chance of showers and thunderstorms for the mountains
for each afternoon beginning on Friday. High temperatures for
inland areas for Sunday and Monday will not be quite as hot.

&&

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

.SHORT TERM (Today through Friday)...
Not much change in temperatures is expected for today with slight
warming on Thursday and a little greater warming for Friday and
Saturday. High temperatures for today through Saturday will warm a
few degrees near the coast to around 5 degrees for inland areas.

Night and morning low clouds will continue to spread inland into
coastal areas each night and into the far western valleys
occasionally late each night.

There could be a few showers over the mountains on Thursday
afternoon as shown by some of the higher-resolution models
including the HRRR, CANSAC WRF, and RRFS with a few showers and
isolated thunderstorms possible on Friday afternoon. Chances for
measurable rainfall are 15 percent or less each day.

&&

.LONG TERM (Saturday through Tuesday)...
High temperatures on Saturday will range from few degrees above
average near the coast to 5 to 10 degrees above average for the
deserts. High temperatures on Saturday will range from the mid 70s
to lower 80s near the coast to the mid 90s to 105 for the Inland
Empire with 112 to 116 for the lower deserts. On Saturday, there
will be moderate HeatRisk for the mountains and Inland Empire with
major to locally extreme HeatRisk for the deserts.

For Sunday and Monday, high pressure will slowly weaken with the
flow aloft becoming more southeasterly. Low-level moisture will
slowly increase for the deserts with high temperatures becoming
not quite as hot for inland areas.

High temperatures on Monday will be mostly within a few degrees of
average to a few to around 5 degrees above average for the
deserts. High temperatures on Monday will range from the mid 70s
to lower 80s near the coast to the 90s to around 100 for the
Inland Empire with 106 to 110 for the lower deserts.

&&

.AVIATION...
050500Z....Coasts/Valleys...Patchy low clouds at the beaches this
hour will slowly increase in coverage and spread about 15 miles or
more inland by 14Z. Expect bases 1000 to 1300 ft MSL with CIG
impacts at coastal TAF sites 06Z-18Z. Minor CIG and VIS impacts
possible at KONT around 14Z. Patchy fog could reduce VIS to 3-5
miles where clouds and terrain intersect. Expect clearing from
inland to the coast around 18Z followed by VFR conditions through
00Z Thu.

Mountains/Deserts...SCT-BKN clouds AOA 20,000ft MSL with
unrestricted VIS through Wed afternoon.

&&

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

&&

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

     Extreme Heat Warning until 8 PM PDT Saturday for Apple and
     Lucerne Valleys-Coachella Valley-San Diego County Deserts-
     San Gorgonio Pass near Banning.

PZ...None.

&&

$$

PUBLIC...17
AVIATION/MARINE...PG

NWS San Diego (SGX) Office