Tustin Foothills, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

136
FXUS66 KSGX 041616
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
916 AM PDT Wed Jun 4 2025

.SYNOPSIS...
Moisture over southwestern California will slowly decrease today
and Thursday, with decreasing chances for afternoon and early
evening showers and thunderstorms in the mountains and high
desert. Dry for Friday into next week, with a warming trend
through the weekend. High temperatures will peak Sunday and
Monday at a few to around 5 degrees above average for coastal
areas and 5 to 10 degrees above average for the mountains and
deserts. Night and morning coastal low clouds will cover much of
the valleys into Thursday, then not spread as far into the valleys
for the weekend into early next week as the marine layer becomes
shallower.

&&

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

This morning...The low pressure system that brought us showers and
tstms yesterday has moved east into AZ and currently there are only
a few light showers over the lower Colorado River valley. Residual
moisture and daytime heating could bring showers and tstms to the
mtns this afternoon. A minor shortwave embedded in the northerly
flow over CA will reach SoCal this afternoon and could enhance the
convective potential and any showers/tstms that develop over the
mtns could also move into the deserts. The marine layer remains
almost 3000 ft deep with a thick saturated layer which is
producing patchy drizzle west of the mtns where low clouds cover
most of the area. A relatively weak inversion should allow for
clearing of the low clouds for at least partial sunshine in the
coastal areas this afternoon.

The atmosphere over SoCal will steadily become drier today through
tomorrow for decreasing chances of afternoon showers/tstms as
conditions become more stable.

In spite of broad troughing over the western US through Friday with
a closed upper low developing off the CA coast on Sat, temperatures
will slowly rise through the weekend. Friday high temperatures
will be mostly within a few degrees of average, ranging from
around 70 near the coast to the 80s for the Inland Empire, with
100 to 104 for the lower deserts.

As we move into the weekend, the sub-tropical high over northern Mexico
will build over AZ and extreme southeastern CA. Slow warming will
continue through the weekend with the heat peaking on Sunday and
Monday. High temperatures for Sunday will range from a few to
around 5 degrees above average for coastal areas and 5 to 10
degrees above average for the mountains and deserts. High
temperatures on Sunday will range from the lower 70s near the
coast to the mid 80s to mid 90s for the Inland Empire, with 105
to 110 for the lower deserts. The marine layer will become
shallower with night and morning coastal low clouds not spreading
as far into the valleys.

Not unexpectedly, model solutions diverge as we move into next
week so there is measurable uncertainty in the forecast details.
In general, we will see the sub-tropical ridge expand westward but
remain to our south with weak ridging over the west coast. We can
expect dry conditions to persist through the middle of next week
with a shallower marine layer modifying temperatures near the
coast. Inland temperatures will remain mostly several degrees
above average.

&&

.AVIATION...
041515Z....Coast/Valleys...A low cloud deck covering the entire
coastal basin will have fluctuating cigs between 1000-3000 feet MSL
and tops to 3500 feet. Areas of vis restricted 2-5SM in -DZ/BR
possible through about 18Z this morning. Clearing inland through 18Z
and near the coast 17-20Z, though portions of the San Diego County
coast likely to remain BKN through the afternoon, but with more
consistent cigs 1500-2000 ft MSL. Low clouds to push inland after
00Z and fill most of the coastal basin overnight into Thursday. 60%
chance for cigs at both KONT and KSBD by 12Z Thu. Bases 1000-1500
feet MSL and inland vis reduced 3-5SM in BR. Clearing Thu morning 15-
17Z for inland areas, 17-18Z for Orange County coast, and only
partial clearing for San Diego County coastal areas 18-20Z.

Mountains/Deserts...FEW-SCT clouds 10000-15000 feet MSL this
morning. ISO SHRA/TSRA based at 10000 feet MSL over the mountains
and high desert 19-01Z. Turning mostly clear thereafter.

&&

.MARINE...
No hazardous marine conditions are expected today through Sunday.

&&

.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...CSP