Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 060423
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
923 PM PDT Tue Jul 5 2022

.SYNOPSIS...
Expect a gradual warming trend through the weekend, with high
temperatures Saturday through Monday up to 5 degrees above
average for many inland areas. Areas near and along the immediate
coast will remain relatively cool during much of this period due
to marine layer low clouds each morning. Cloud coverage will
spread into the valleys each morning through Thursday, after which
the marine layer will become shallower and mostly confined to
coastal areas.

&&

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

This evening, the marine layer is about 2,000 ft deep with cloud
bases 1,500-1,700 feet. Low clouds have begun to drift ashore,
mainly in San Diego County and could spread up to 20 miles inland
by early Wednesday morning. Sfc pressure gradients remain onshore
and are strong enough to support westerly winds gusting 25-30 mph
in favored locations. Winds will continue to weaken overnight
with the diurnal cycle.

From previous discussion...
The upper level high over the Central US will begin to strengthen
and expand westward this week while an upper level low and
attendant trough near the BC/WA coasts remains in place. This will
favor a gradual warming trend through the remainder of the week
while onshore flow persists at the coast, keeping temperatures
relatively cool. High temperatures each day will warm up by a
degree or two for most inland areas. The coast, on the other hand,
will see highs remain relatively steady as the persistent onshore
flow and marine layer clouds each morning inhibit daytime
heating. The marine layer will become more and more shallow
through Thursday as the Central US high expands westward over the
Four Corners region. By Friday, marine layer clouds and fog will
be mainly confined to coastal areas.

The warmest temperatures of the period will likely occur Saturday
through Monday as the upper high over the Four Corners region
peaks in strength at around 597dm. The immediate coast and
coastal valleys will see their warmest day on Saturday, while the
deserts and Inland Empire see highs peak on Sunday and remain
fairly similar on Monday, perhaps a degree or two cooler in spots.
Highs will top out up to 5 degrees above seasonal average for
many inland areas this weekend. This translates to the middle and
upper 70s along the coast and the middle to upper 80s in the
coastal valleys on Saturday, the middle and upper 90s in the
Inland Empire on Sunday, between 99-102 degrees in the high
deserts Sunday and Monday, and around 110-113 for the lower
deserts and the Coachella Valley on Sunday and Monday.

Dry weather is expected to continue through early next week with
any monsoonal moisture remaining well off to our east. The more
likely chances for more substantial moisture return will be during
the middle portions of next week as the upper high over the Four
Corners shifts back a bit westward. This may allow for some
middle and upper level moisture plumes to wrap around the southern
periphery of the high and into portions of Southern California.
EPS/GEFS guidance continue to carry some precipitation chances
heading into the middle portions of next week, which will be
closely monitored. PoPs below 10 percent will be maintained given
the inherent uncertainty with timing and placement of any
potential rain chances.

&&

.AVIATION...
060350Z...Coast/Valleys...BKN-OVC with bases 1400-1800 FT MSL are
filling in across coastal San Diego county, and will develop across
Orange County after 05z Wed. Low clouds will spread up to 25 SM
inland. Scatter out 16-18z Wed.

Mountains/Deserts...Mostly clear with unrestricted vis through Wed.
W-NW winds with surface gusts of 20-30 knots possible through 08z
Wed before diminishing.

&&

.MARINE...
A Small Craft Advisory is in effect for the Outer Waters through
midnight tonight for northwest winds gusting to 25 knots near San
Clemente Island and steep, short-period wind waves. Winds weaken
tonight, then strengthen again Wednesday afternoon with gusts to 20
kt. No hazardous marine weather Thursday through Sunday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory until midnight PDT tonight for Waters from
     San Mateo point to the Mexican Border Extending 30 to 60 nm
     out including San Clemente Island.

&&

$$

PUBLIC...PG/Adams
AVIATION/MARINE...Schenk


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