San Diego Weather at Mission Trails, CA

000
FXUS66 KSGX 112050
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
150 PM PDT Sat Jul 11 2020

.SYNOPSIS...
The weather will be exceptionally hot this weekend with strong high
pressure over the Southwest. Coastal temperatures will be
somewhat moderated by sea breezes. Increasing moisture aloft will
bring occasional high clouds and a slight chance for showers, mainly
over the mountains. Temperatures will slowly trend lower early next
week as the high aloft weakens. Seasonal weather will prevail later
next week with a weak trough along the West Coast.

&&

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

There was a lot of hot air over the Southwest today, with record
breaking heat in some areas. Ramona reached 101 at 1 PM, which
eclipsed the previous record of 100 set in 1983. Other records
that are within reach today include Riverside (105) and El Cajon
(99). A Record Report will be issued around 5:30 PM. Other
noteworthy temperatures at 1 PM: Escondido (98), Hemet (104), Palm
Springs (113), and Apple Valley (103). The sea breeze moderated
temperatures near the coast where the San Diego Airport was 79.

High clouds were streaming in from the southeast today around the
the southwestern edge of the 600 dm high over New Mexico. Cloud
growth was stunted due to weak instability, and virga is all that
has been reported so far. A few light showers are possible through
the evening as the cloud band moves north from San Diego County into
San Bernardino County. The 12Z NKX sounding this morning had a
Precipitable Water of 1.24" compared to 1.06" Friday morning.

Sunday will be another hot day, not too much different than today.
The lower deserts may be a degree or two hotter, and the coastal and
valley areas may be a degree or two cooler as the upper high begins
to relent. But overall it will be a scorcher. There isn`t any
indication of an MCS forming yet over Sonora, Mexico, which is where
the debris clouds over San Diego and Riverside County came from. If
that doesn`t materialize then it would be a sunnier day in these
areas.

There are small chances of precipitation through Sunday, mainly in
the mountains, but most areas will only see virga. Weak radar echoes
dissipated as they moved from northern Baja into San Diego
County, and cumulus buildups over the San Bernardino Mountains
showed very little vertical growth today. Shower chances are small
due to weak instability and synoptic scale subsidence associated
with the upper high over New Mexico and Arizona.

Early next week a trough sets up along the West Coast and the upper
ridge axis retreats farther east. Lowering heights, stronger onshore
flow and a slowly deepening marine layer will return temperatures to
their seasonal norms by midweek. Patchy dense fog may form again
Sunday morning in the coastal areas, then gradually spread a little
farther inland each day through Wednesday.

The weak Pacific trough retrogrades a few hundred miles westward
late next week, and an upper ridge anchors near the Four Corners.
This pattern remains in place through next weekend which means
temperatures will be at or slightly above average, and the monsoon
signal will remain fairly weak.

&&

.AVIATION...
112025Z...Coast...SCT-BKN clouds AOA 15,000 ft MSL this afternoon
into tonight. Moderate confidence of patchy low clouds returning
tonight after 09Z. Bases a little lower than they were this morning
with some places seeing bases 300-800 ft MSL. Look for these cigs to
clear 14-15Z Sunday.

Valleys/Mountains/Deserts...SCT CU/ISO TCU may developing over the
mountain crests this afternoon with bases near 8000 ft MSL and tops
to 20000 ft MSL, dissipating near sunset. Some of these mid level
clouds 15,000 ft MSL will prevail through the night and into Sunday
morning.

&&

.MARINE...
Patchy fog for portions of the coastal waters this evening through
Sunday morning, though confidence still somewhat on the low end.
Some areas may experience visibility of less than 1 nm. Otherwise,
no hazardous marine conditions are expected through Wednesday.

&&

.SKYWARN...
Skywarn activation will not be needed this weekend.
&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 8 PM PDT Monday for Apple and
     Lucerne Valleys-Coachella Valley-San Diego County Deserts-
     San Gorgonio Pass Near Banning.

     Heat Advisory until 8 PM PDT Sunday for Orange County Inland
     Areas-Riverside County Mountains-San Bernardino County
     Mountains-San Bernardino and Riverside County Valleys-The
     Inland Empire-San Diego County Mountains-San Diego County
     Valleys-Santa Ana Mountains and Foothills.

PZ...NONE.

&&

$$

PUBLIC...Moede
AVIATION/MARINE...APR