Costa Mesa, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

924
FXUS66 KSGX 102044
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
144 PM PDT Thu Jul 10 2025

.SYNOPSIS...
Hot inland and cool at the coast for the rest of today. Friday
will cool a little, with minor day to day changes through the
middle of next week. A deepening marine layer will bring more
coastal clouds extending farther inland during the nights and
mornings.

&&

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

Temperatures were running very similar to those yesterday as of
midday, some a little higher and others a little lower. Deserts
are a little cooler, while many inland valleys are a little
warmer. Areas of low clouds are sticking to the beaches in San
Diego County. Temperatures today show a great contrast from the
temperate coast to the scorching desert. The midday temp was 67 at
Oceanside Harbor and 114 in Ocotillo Wells. While it doesn`t
appear desert temps will reach those record levels of yesterday,
extreme heat warnings are warranted and still in place for the
lower deserts through sunset. In the valleys, highs will be in the
90s to about 106 and a heat advisory is out today, particularly
for the more inland valleys where a few temps in spots already
exceed 100. These inland highs represent 6 to 12 degrees above
normal today. A Heat Advisory remains in effect through sunset. A
temporary but strong ridge overhead has brought our region the
kind of subsidence and compressional heating needed for this heat
episode. This should be the final day of extreme heat. This high
will weaken slightly Friday, and some additional gulf moisture
creeps into the lower deserts, allowing for a drop of several
degrees, but still up to 8 degrees above normal in the low desert
for mid July. Valleys will trend close to normal for the weekend.
The marine layer will get a boost by a coastal eddy tonight and
Friday to rebuild and extend low clouds and fog into western
valleys and for a longer time each night and morning. For next
week, minor variations in the upper high will maintain this rather
seasonal weather, except slightly hotter than average in the
deserts. There are hints of monsoon moisture increasing next
Wednesday through Friday for an extremely slight (but nonzero)
chance of showers and thunderstorms across the southern interior.
We`ll need more consistency and consensus in ensemble solutions
that far out to add precip to the forecast.

&&

.AVIATION...
102045Z....Coast/Valleys...Low clouds (based ~1000-1400ft MSL) have
stuck around along the south-central San Diego County beaches this
afternoon. Otherwise, clear skies and VFR conditions prevail through
the day. Aided by a coastal eddy tonight, low clouds fill back in
and push ashore tonight with slightly higher bases and more inland
extent. 70% chance for CIGs at KSAN by 06z with KCRQ likely closer
to 09z. Clouds may reach KSNA around 10-14z, but there is about a 40-
50% chance of this. Bases will be closer to 1000-1500ft MSL with
about 10-15 miles of inland extent. Scattering back to the beaches
by 16-17z Friday.

Mountains/Deserts...VFR conditions and unrestricted VIS through
Friday afternoon.

&&

.MARINE...
No hazardous marine conditions expected through Monday.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT this evening for Riverside County
     Mountains-San Bernardino and Riverside County Valleys-The
     Inland Empire-San Diego County Mountains-San Diego County
     Valleys.

     Extreme Heat Warning until 8 PM PDT this evening for Coachella
     Valley-San Diego County Deserts-San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

PUBLIC...MM
AVIATION/MARINE...Munyan