505
FXUS66 KSGX 071632
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
932 AM PDT Mon Jul 7 2025

.SYNOPSIS...
Warming conditions through the middle of the week, with the hottest
days expected to be Wednesday and Thursday for inland locations.
Conditions will return to near normal for the weekend into early
next week. For early this week, night and morning low clouds and fog
will reach into the western valleys becoming shallower for the
middle to end of the week.

&&

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

Highs today are expected to be similar to yesterday`s as an upper
level low remains centered off the coast of northern California. The
low will remain in place into Tuesday before moving inland
through northern California Tuesday night into Wednesday. Three to
five degrees of warming is expected for Tuesday with an
additional few degrees of warming into Wednesday. The marine layer
will still reach into the western valleys tonight into Tuesday
morning. The marine layer will decrease to around 1500 feet in
depth on Wednesday, keeping low clouds and fog more confined to
coastal areas Wednesday and Thursday mornings.

An area of high pressure aloft will strengthen over the southwestern
United States and expand west across Southern California for
Wednesday and Thursday. That will bring a notable increase in high
temperatures, especially for the deserts. West of the mountains,
highs on Wednesday and Thursday will be four to seven degrees
above average with highs in the deserts 10 degrees above average.
High temperatures Wednesday and Thursday will range from the 70s
near the coast; the upper 90s to 104 for the Inland Empire; and
114 to 118 for the lower deserts. In the mountains, areas below
5000 ft have a 90+ percent chance of exceeding 90 degrees.
Widespread moderate HeatRisk is expected for the valleys and
mountains, with widespread major HeatRisk in the low deserts. Make
sure you`re staying hydrated, seeking shade, and avoiding
strenuous activity during the hottest parts of the day if
possible.

High pressure aloft will remain over Southern California into early
next week, but it expected to weaken. The weakening of the high will
result in a gradual cooling trend for Friday into early next week.
For next Sunday and Monday, NBM high temperatures for the coast and
valleys will be near to around five degrees below average with
the deserts around five degrees above average. High temperatures
for next Sunday will range from the lower to mid 70s near the
coast to the upper 80s to upper 90s for the Inland Empire with 110
to 114 for the lower deserts. The marine layer will deepen to
1500 to 2000 feet by next Sunday and Monday with high and morning
coastal low clouds extending inland to the western valleys.

&&

.AVIATION...
071530Z....Coast..Low clouds 1200-1800 feet MSL will clear coastal
airports by 17Z. Mostly clear skies thereafter, but with patchy low
clouds on immediate coast. Low clouds in more patchy coverage will
gradually develop after 05Z with less probability and duration
around KSNA. Bases will be around 700-1100 feet MSL with vis reduced
to 1-5SM in BR along inland coastal areas. Scatter out Tuesday 14-
16Z. Increasing clouds above 12000 feet Tuesday.

Valleys/Mountains/Deserts...Clear with unrestricted VIS today and
tonight. Increasing clouds above 12000 feet Tuesday.

&&

.MARINE...
NW wind gusts around 20 kts near San Clemente Island Tuesday
afternoon and evening. Otherwise, no hazardous marine weather is
expected through Friday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning from 10 AM Wednesday to 8 PM PDT Thursday
     for Coachella Valley-San Diego County Deserts.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE...MM