101
FXUS66 KSGX 201859
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1159 AM PDT Sat Jun 20 2026

.SYNOPSIS...
Below average temperatures with marine layer low clouds and fog
reaching into portions of the valleys this weekend. For the first
half of the week, widespread moderate to areas of major HeatRisk
possible for the deserts and widespread minor to locally moderate
HeatRisk for inland Orange County, valleys, and mountains. The
marine layer will become shallower next week, staying confined to
coastal locations. Gradual cooling expected for the second half of
the week.

&&

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

At 11:30 AM, temperatures were running 3 to 7 degrees warmer than
yesterday in the Inland Empire, San Bernardino mountains, and inland
Orange County with temperatures similar to a few degrees cooler than
11:30 AM yesterday elsewhere. Visible satellite is showing
partial clearing along the immediate coast, with the potential for
widespread clearing this afternoon. Low clouds are expected to
reach into portions of the valleys again overnight into Sunday
morning. Highs Sunday are expected to remain below average but
will trend a few degrees warmer than today.

Additional warming is expected into the middle of the week as a
ridge of high pressure builds aloft from the south. Current forecast
has high temperatures for inland locations 5 to 10 degrees above
average with localized areas of moderate HeatRisk away from the
coast and areas of major HeatRisk in the low desert by Wednesday.
The forecast has trended cooler by a few degrees for Tuesday
through Thursday, which has limited the geographic extent of
moderate HeatRisk in the valleys and major HeatRisk in the low
desert. Based on the current forecast, hottest day is expected to
be Wednesday with Tuesday and Thursday a few degrees cooler than
Wednesday.

Guidance continues to indicate an increase in precipitable water for
the middle to end of next week. This will most likely result in
limited daytime heating, warmer than normal overnight low
temperatures, and more humid feeling conditions. As far as the
marine layer goes, the building high pressure and influx of
moisture will result in a shallower marine layer and limited low
cloud development. While the most likely scenario is for dry
conditions to prevail, there is a 10-15 percent chance showers or
thunderstorms may develop over area mountains Wednesday afternoon.

Most ensemble solutions are now on board with a shortwave trough
moving into the Pacific Northwest by Thursday. This will displace
the ridge aloft and result in a gradual cooling. By next Saturday,
conditions are expected to be within a few degrees of normal.

&&

.AVIATION...
201800Z...Coast/Valleys...Low clouds have be scattering out more
efficiently across coastal San Diego County this morning compared to
Orange County, with CIGs likely to persist at KSNA until 19-20z. VFR
prevailing into the afternoon with low clouds set to redevelop and
fill back ashore around 01-03z Sunday, initially at KSAN/KCRQ,
eventually spreading to Orange County (KSNA) and the inland valleys
by 09z. Higher chance for CIGs to spread into the Inland Empire
compared to this morning, with a ~60% chance for CIGs at KONT
between 12-16z and a ~30% chance at KSBD. Cloud bases will be
similar to last night/this morning, likely 1700-2000ft MSL during
the early overnight hours, then lifting to 1900-2300ft MSL around
12z. Clouds set to scatter back to the coasts around 17-18z Sunday.

Mountains/Deserts...VFR conditions expected through the TAF period.
Westerly wind gusts of 25-40 kts pick up through mountain passes
into deserts after 20z this afternoon. Local VIS reductions 4-6 SM
in BLDU during periods of strong gusts and moderate up/downdrafts in
lee of mtns.

&&

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

&&

.BEACHES...
Elevated surf and strong rip currents are set to continue through
this weekend with a persistent long period southwesterly swell. Surf
of 3-5 feet with local sets to 6 feet are expected at southwest-
facing beaches. Expect locally hazardous swimming conditions with
high rip current and longshore current risk. See the Beach Hazards
Statement for more details.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Sunday evening for Orange County
     Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE/BEACHES...Munyan

NWS San Diego (SGX) Office