967
FXUS66 KSGX 291625
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
925 AM 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 morning...A shallow marine layer enabled low clouds and fog
to spread about 10-15 miles inland, but the clearing has begun and
we can expect sunny skies this afternoon, although low clouds
could linger at some beaches due to a strong marine layer
inversion. The sounding and satellite imagery also show some
moisture in the mid levels moving north in the southerly flow
aloft. This 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...
291615Z....Coast/Valleys...Low cloud bases have lifted to 900-1300ft
MSL with the Sun up and are eroding nicely this morning. Expecting
clearing to the coasts by 1700z with mostly clear conditions through
the afternoon, and only about a 20% chance that SCT/BKN clouds
linger near San Diego County beaches through the afternoon. Low
clouds 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.

.Mountains/Deserts...SW/W wind gusts 25-35 kts across the deserts
and mountain passes 20z this afternoon through about 05z Monday,
leading to MOD UDDFS just east of the mountains. Winds weaken again
overnight tonight.

&&

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

&&

.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