Costa Mesa, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

860
FXUS66 KSGX 311608
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
908 AM PDT Thu Jul 31 2025

.SYNOPSIS...
Through Tuesday of next week, high temperatures will mostly
fluctuate between a few degrees below average and around 5 degrees
above average. For Wednesday and Thursday of next week,
strengthening high pressure aloft centered over New Mexico will
bring warming of high temperatures of a few degrees each day.
Night and morning coastal low clouds will spread into portions of
the western valleys late each night.

&&

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

.Morning Update...

Low clouds continue to fade out of the western valleys and near
the coast this morning, with mostly clear skies in the next couple
of hours. Clouds will fill back in similarly again tonight with
mostly clear skies for the region for much of Friday. Quiet
weather continues with no forecast updates.

.Previous Discussion (142 AM Thursday)...

.SHORT TERM (Today through Saturday)...
Tide gauges show periodic fluctuations in water levels of a few
inches at Scripps Pier in La Jolla and the Broadway Pier in San
Diego Bay have continued since the initial arrival of tsunami
waves early Wednesday morning, the result of the 8.8 magnitude
earthquake off the coast of the southern Kamchatka Peninsula.
These minor fluctuates could continue for a few more days based on
the extended period of water level fluctuations following the
eruption of an undersea volcano near Tonga in the south Pacific in
January 2022 and the resulting tsunami.

High temperatures through Monday will mostly fluctuate between a
few degrees below average and around 5 degrees above average. High
temperatures will warm slightly today, not change much on Friday,
then warming slightly again on Saturday with Saturday high
temperatures ranging from the 70s near the coast to the 90s for
the Inland Empire with 108 to 114 for the lower deserts. The
marine layer will remain around 1500 feet deep with night and
morning coastal low clouds spreading into portions of the western
valleys late each night.

&&

.LONG TERM (Sunday through Wednesday)...
Not much change in high temperatures is expected on Sunday with
slight cooling for Monday and Tuesday. Strengthening high pressure
centered over New Mexico will bring warming of a few degrees per
day for Wednesday and Thursday with high temperatures on Thursday
ranging from the mid 70s to lower 80s near the coast to the mid
90s to 104 for the Inland Empire with 112 to 116 for the lower
deserts. The marine layer will fluctuate between 1500 and 2000
feet deep with night and morning coastal low clouds spreading
into portions of the western valleys late each night.

&&

.AVIATION...
311530Z....Coasts/Western Valleys...Low clouds and fog with bases
800-1200 feet MSL, tops to 1600 feet, and vis 1-3SM over higher
terrain will scatter out 16-17Z. Low clouds with similar bases and
reduced vis will develop and move locally inland tonight after 05Z
with similar areal coverage. Scatter out Friday 16-17Z.

.Inland Valleys/Mountains/Deserts...Mostly clear with VFR conditions
through Friday morning.

&&

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

&&

.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...APR/17
AVIATION/MARINE...MM