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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS66 KSGX 131037
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
330 AM PDT Sat Apr 13 2024

.SYNOPSIS...
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A trough of low pressure will bring cool, breezy weather this
weekend with scattered light showers at times. Snow showers will
fall in the mountains above 6,000 feet. The trough will move east
Sunday night, and dry weather is forecast next week.
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&&

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

The marine layer deepened to 4,000 feet last night with low clouds
filling the Cajon and San Gorgonio Passes this morning. Despite the
deeper marine layer, there weren`t any reports of drizzle west of
the mountains through 3 AM. Steady deepening to 5,000 feet ahead of
a trough digging down the California coast will bring increasing
chances of light showers this afternoon in the San Bernardino
Mountains and foothills where orographically enhanced lifting of
this moist layer will increase the rain chances. Also, a narrow IVT
ribbon of 250-300 kg/m/s traverses this area late this afternoon.
Showers will spread south and east into Riverside and San Diego
Counties through evening, then taper off and end overnight.

A second shortwave rounding the base of the long wave trough will
bring another chance of showers in the Sunday afternoon and Sunday
night. This will be a colder system with less available moisture, so
the showers will not be as widespread as with the first shortwave on
Saturday.

Rainfall totals will range from 0.05-0.30" in the coastal and valley
zones, with the higher end of the range in Orange and San Bernardino
Counties, and the lower amounts in San Diego County. In the
mountains from 0.25-1.00" is forecast, highest in San Bernardino
County and lowest in the San Diego County mountains. A few hundreds
of an inch is all that will fall in the High Deserts. The Lower
Deserts will remain dry.

Snow levels around 5500-6500 feet on Saturday will fall to 4500-5500
feet Sunday, with snow total of 3-7" possible above 7000 feet in San
Bernardino County Mountains where a Winter Weather Advisory is in
effect through Sunday evening.

It will be windy at times this weekend. The strongest winds will
likely be Saturday afternoon and evening in the mountains and
deserts with gusts of 40-60 mph are forecast. Breezy southwest winds
will also impact the coastal and valley zones with gusts to 25 mph.
A second round of gusty winds will develop Sunday afternoon and
evening as the second shortwave passes over Southern California.

The low quickly moves to the east on Monday, and ensemble guidance
supports warming over Southern California through the middle of next
week.
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&&

.AVIATION...
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130900Z...Coast/Valleys...Widespread BKN/OVC clouds will prevail
through Sun morning with bases 2500-4000 ft MSL and tops to 6000-
10000 ft MSL. Local VIS 3-5 mi will occur in SHRA mainly 22Z Sat-05Z
Sun.

Mountains/Deserts...Areas of terrain obscurations will occur at
times mainly on the coastal slopes in clouds/SHRA/SHSN through Sun
morning and beyond. Surface gusts 25-45 kt from the S/W will
continue from the mountain crests through the desert slopes and into
the deserts through 12Z Sun, with increasing winds again after 18Z
Sun, along with LLWS and MOD UDDFS.
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&&

.MARINE...
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South winds will develop this morning and will be associated with
gusts between 20 and 25 knots at times, including near Zuniga
Jetty/San Diego Bay Entrance, until the front arrives from the west
late this afternoon/early this evening when a few gusts 20 to 25
knots will also occur. A Small Craft Advisory has been issued for
these gusts 8 AM-8 PM for the inner/outer coastal waters (0-60 NM
from the coast). Otherwise, a couple periods of rain showers will
occur late today/this evening and Sunday late afternoon/evening.
Local gusts over 20 knots could also occur Sunday and Monday from
the west. Winds will be lighter beginning Tuesday.
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&&

.SGX WATCHES/WARNINGS/ADVISORIES...
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CA...Wind Advisory from noon today to 11 PM PDT this evening for
     Apple and Lucerne Valleys-San Bernardino County Mountains.

     Winter Weather Advisory from noon today to 8 PM PDT Sunday for
     San Bernardino County Mountains.

     Wind Advisory from 3 PM this afternoon to 11 PM PDT this evening
     for Riverside County Mountains-San Diego County Deserts-San
     Diego County Mountains-San Gorgonio Pass Near Banning.

PZ...Small Craft Advisory from 8 AM this morning to 8 PM PDT this
     evening for Coastal Waters from San Mateo Point to the
     Mexican Border and out to 30 nm-Waters from San Mateo Point
     to the Mexican Border Extending 30 to 60 nm out including
     San Clemente Island.
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&&

$$

PUBLIC...Moede
AVIATION/MARINE...Maxwell