Placentia, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

695
FXUS66 KSGX 080418
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
918 PM PDT Mon Jul 7 2025

.SYNOPSIS...
Warming conditions through the middle of the week, with the hottest
days expected to be Wednesday and Thursday for inland locations.
Conditions will return to near normal for the weekend into early
next week. For early this week and the weekend, night and morning
low clouds and fog will reach into the western valleys becoming
shallower for the middle to end of the week.

&&

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

This evening...The marine layer is similar in depth to yesterday
evening with a similarly strong inversion. Low clouds are forming
along the coast at this hour and will likely spread about 10-15
miles inland by sunrise.

From previous discussion...
An upper level low will remain centered off the coast of northern
California into Tuesday. The low is expected to move inland
through northern California Tuesday night into Wednesday. Three to
five degrees of warming is expected for Tuesday with an
additional few degrees of warming into Wednesday. The marine
layer will decrease to around 1500 feet in depth on Wednesday,
keeping low clouds and fog more confined to coastal areas
Wednesday and Thursday mornings.

An area of high pressure aloft will strengthen over the southwestern
United States and expand west across Southern California for
Wednesday and Thursday. That will bring a notable increase in high
temperatures, especially for the deserts. Highs on Wednesday and
Thursday are expected to be 5 to 10 degrees above average for inland
locations. High temperatures Wednesday and Thursday will range from
the 70s near the coast; the upper 90s to 104 for the Inland Empire;
and 114 to 118 for the lower deserts. In the mountains, highs are
expected to range from in the mid-80 to upper 90s with the warmest
conditions expected below 5000 ft. Widespread moderate HeatRisk
is expected for the valleys and mountains, with widespread major
HeatRisk in the low deserts. Make sure you`re staying hydrated,
seeking shade, and avoiding strenuous activity during the hottest
parts of the day if possible.

High pressure aloft will remain over Southern California into early
next week, but is expected to weaken. The weakening of the high
will result in a gradual cooling trend for Friday into early next
week. For next Sunday and Monday, NBM high temperatures for the
coast and valleys will be near to around five degrees below
average with the deserts around five degrees above average. The
marine layer will deepen to 1500 to 2000 feet by next Sunday and
Monday with night and morning coastal low clouds will extend
inland to the western valleys.

&&

.AVIATION...
080300Z....Coast...Low clouds with patchy coverage currently
offshore will gradually move inland to about 10 miles after 05Z.
Less probability for low clouds (about a 60% chance for impacts by
12Z tonight) and likely a shorter duration around KSNA. Bases will
be around 700-1100 feet MSL with vis reduced to 1-5SM in BR along
inland and higher elevation coastal areas. Scatter out Tuesday 14-
16Z. Increasing upper level clouds above 12000 ft Tuesday. Patchier
low clouds with slightly lower bases than tonight not likely to form
until after 09Z Wed.

Valleys/Mountains/Deserts...Clear with unrestricted VIS today and
tonight. Increasing clouds above 12000 feet Tuesday.

&&

.MARINE...
NW wind gusts around 20 kts near San Clemente Island Tuesday and
Wednesday in the afternoons and evenings. Otherwise, no hazardous
marine weather is expected through Friday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 10 AM Wednesday to 8 PM PDT Thursday for
     Riverside County Mountains-San Bernardino and Riverside
     County Valleys-The Inland Empire-San Diego County Mountains-
     San Diego County Valleys.

     Extreme Heat Warning from 10 AM Wednesday to 8 PM PDT Thursday
     for Coachella Valley-San Diego County Deserts.

PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE...CSP