299
FXUS66 KSGX 300409
AFDSGX

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

.SYNOPSIS...
Continued hot inland on Sunday with high temperatures 3-8 degrees
above normal. 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 in
the mountains and deserts for Wednesday through next weekend.
During this time, the marine layer deepens somewhat, extending its
influence further inland.

&&

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

Low clouds cleared well off the coast this afternoon, but have
already begun to redevelop along the San Diego County coast this
evening. Expect clouds to continue to expand northward towards
Orange County and eventually around 10-15 mi inland overnight.
Otherwise clear tonight aside from smoke over parts of the Inland
Empire and San Gorgonio Pass from ongoing wildfires.

An upper level high centered near the AZ/NM border and an upper
level low centered about 440 miles west of San Diego will remain
in place through mid-week. This will continue hot weather inland
with highs around 3-8 degrees above normal. For Monday, the chance
of high temperatures in the low deserts exceeding 110 degrees is
60-100%, with the greatest chances in the Coachella Valley.

The upper level low to the west slowly shifts eastward and over So
Cal Tuesday into Wednesday, bringing cooling and a slight
deepening of the marine layer. By Wednesday high temperatures will
return to near to slightly below normal. For the rest of the week
into next weekend, ensembles are in generally good agreement with
weak troughing remaining near the West Coast with several short
waves moving through the mean flow. This will maintain high
temperatures a few degrees below normal and night and morning low
clouds and fog in the coastal areas and western valleys. Both the
EPS and GEFS ensembles show an increase in PW sometime early next
week which could bring our first round of monsoon thunderstorms,
but we`ll have to wait and see if it holds.

&&

.AVIATION...
300300Z....Coast/Valleys...Low clouds based 600-1000 ft MSL are
currently building over the ocean and will push onshore 06-09z
tonight with eventually a 10-15 mile inland extent. KSAN and KSNA
may start out tonight with IFR CIGs, then 40% chance bases lift
above 1000 ft MSL 12-14z early Monday. VIS restrictions limited to
localized inland valleys and where clouds intersect higher terrain.
Scattering back to the coasts by 16-17z Monday morning. Low clouds
with slightly higher bases return to the coast 02-05z Tuesday.

With small active fires burning in the Inland Empire, HZ/FU are
possible with reductions of VIS 3-5SM for eastern portions of the IE
through Monday.

.Mountains/Deserts...FU/HZ possible in the Coachella Valley
through Monday with small active fires in the Inland Empire. Once
again, SW/W wind gusts 25-35 kts are expected for the deserts and
mountain passes Monday afternoon, leading to periods of MOD UDDFS
just east of the mountains. Otherwise, VFR conditions prevail
through Monday evening.

&&

.MARINE...
Monday and Tuesday afternoons will feature NW winds of 15 kts with
gusts approaching 20 kts near San Clemente Island. Otherwise, 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...SS
AVIATION/MARINE...Westerink