492
FXUS66 KSGX 292047
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
147 PM PDT Sun Jun 29 2025

.SYNOPSIS...
Continued hot inland today and tomorrow, with daytime high
temperatures several degrees above seasonal averages. A shallow
marine layer will continue to moderate temperatures near the
coast, with low clouds and fog extending 10 to 15 miles inland
during the nights and mornings. Temperatures begin to trend
downward on Tuesday west of the mountains then the mountains and
deserts follow suit for Wednesday through next weekend. During
this time, the marine layer deepens somewhat, extending its
influence farther inland.

&&

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

This afternoon...Skies are mostly sunny except for a few marine
layer low clouds at the beaches. Some cumulus clouds have formed
over the mountains and drifted over the deserts in the south southwest
flow aloft. These cumulus clouds show very little vertical extent
as they encounter a strong subsidence inversion above 10,000 ft.

The southerly flow over SoCal is due to the prevailing pattern,
with an upper level high centered near the AZ/NM state line and an
upper level low centered about 440 miles west of San Diego. This
pattern will remain in place through mid-week and continue to
bring us hot days for inland areas. For today and Monday, we can
expect temperatures reaching the upper 80s to low 90s in the San
Diego county valleys and the mid to upper 90s for the Inland
Empire, while the high deserts will see temps in the mid to upper
90s and lower deserts 105-110. Sometimes, a pattern like this can
bring the threat of afternoon convection to the mtns and deserts
but current model solutions don`t show the moisture and
instability that would be required for a significant threat of
deep convection.

For Tuesday and Wednesday, the upper low to our west strengthens
and slowly moves east over SoCal. This will likely result in a
deeper marine layer and stronger onshore flow, bringing low clouds
and fog farther inland during the nights and mornings and lowering
temperatures west of the mtns on Tuesday. By Wed, the falling
heights and cooler air associated with the low will begin to
affect the deserts as well. On Wed, we can expect daytime high
temps ranging from 3-4 degrees above normal in the low deserts to
3-5 degrees below normal west of the mtns.

For the rest of the week into next weekend, conditions remain
similar with minor day-to-day variations as a pattern of weak
troughing sets up over the west coast. The details of the forecast
are uncertain due to the spread in model solutions but it seems
likely that conditions will remain dry and temperatures will
remain near or slightly below seasonal averages.

&&

.AVIATION...
292045Z....Coast/Valleys...Low clouds have cleared nicely this
afternoon, with only a few clouds in the vicinity of KSAN. VFR
prevails through this evening with low clouds expected reform
offshore by 02-06z this evening and eventually push back onto the
coast around 06-09z Monday. Similar bases and inland extent expected
as what was seen this morning, about 600-1000ft MSL with about 10-15
miles inland. VIS restrictions limited to localized inland valleys
and where clouds intersect higher terrain. Scattering back to the
coasts by 16-17z Monday morning.

.Mountains/Deserts...SW/W wind gusts 25-35 kts have picked up across
the deserts and mountain passes this afternoon, leading to periods
of MOD UDDFS just east of the mountains. Winds weaken after 05z
Monday. Otherwise, VFR conditions prevail through Monday
afternoon.

&&

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

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE...Munyan