Baldy Mesa, California Weather Forecast Discussion

106
FXUS66 KSGX 130939
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
239 AM PDT Sat Sep 13 2025
.SYNOPSIS...
Daytime high temperatures will remain a little below normal
through Sunday. A minor warming trend is expected for Monday
through Wednesday although temperatures will only be a few degrees
above normal. A relatively deep marine layer will continue through
Sunday before becoming shallower into Wednesday. Some monsoonal
moisture could return for the latter half of next week bringing
chances for a return of showers and thunderstorms, mainly to the
mountains and deserts.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
This morning...The marine layer is 2500-3000 ft deep and low
clouds have spread inland to the foothills of San Diego County.
The low clouds will continue to increase in coverage until about 8
am before beginning to scatter out. The inversion strength is
similar to yesterday so the clearing should follow much the same
timing as yesterday. Elsewhere, skies will remain clear.
Numerical models remain in good agreement through Tuesday with
respect to the placement and timing of synoptic-scale systems.
The extensive low/trough over the western US will move east with
the upper trough axis reaching the Rockies by Sunday morning. A
weak ridge will follow the trough over the West Coast for Monday
through Wednesday with a weak upper level low off the coast of
SoCal by Tuesday. Daytime high temperatures will remain below
seasonal averages through Sunday before warming up for Monday
through Wednesday as the weak ridge brings height rises.
Wednesday will likely be the warmest day with high temperatures
from 1 to 7 degrees above seasonal averages in most areas. The
marine layer will maintain its current depth through Sunday
morning with the nighttime low clouds spreading inland to the
foothills. The marine layer will then become shallower for Monday
through Wednesday limiting the low clouds to the coastal areas and
western portions of the valleys.
For the latter half of next week...The model solutions begin to
diverge, introducing more uncertainty into the forecast. In spite
of the uncertainty, it`s likely that with a weak upper low off
the SoCal coast and a ridge to the east some moisture will be
drawn northward from the tropics. This will bring chances for
showers and possibly tstms Thu-Sat. The moisture will also
restrict the warming and daytime temps will trend lower with
Saturday temps returning to near or a little below seasonal
averages.
&&
.AVIATION...
130930Z...Coast/Valleys...Somewhat patchy low clouds based 1800-2200
ft MSL have developed through most of San Diego and Orange co
coastal areas. Periodic, brief scatter out possible for coastal
sites through about 13Z. Low clouds in the IE (including KONT/KSBD)
likely to become more widespread towards 12Z. Clouds scatter from
inland valleys 16-17Z, then from most coastal areas 17-19Z, though
some patchy low clouds will likely remain along the immediate San
Diego Co coast through about 21Z, and KSAN (and, to a lesser extent,
KCRQ) has about a 40% chance to see occasional BKN CIGs through this
time. Clouds with lower bases 1500-2000 ft MSL to push back inland
after 02Z Sun, moving inland 20-25 miles.
Mountains/Deserts...Mostly clear and VFR conditions through
tonight.
&&
.MARINE...
No hazardous marine conditions are expected through Wednesday.
&&
.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

NWS SGX Office Area Forecast Discussion