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000
FXUS66 KSGX 191620
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
920 AM PDT Fri Apr 19 2024

.SYNOPSIS...
Cooler today with coastal low clouds extending inland across most
of the valleys this morning and with gusty southwest to west
winds for the mountains and deserts for this afternoon into
tonight with the stronger gusts to 45 to 55 mph. Warming for
Saturday and Sunday with Sunday high temperatures a few degrees
above average near the coast to 10 to 15 degrees above average for
inland areas. Greater cooling will spread inland for Monday
through Thursday with Thursday high temperatures as much as 10 to
15 degrees below average for the mountains and inland valleys.
Coastal low clouds will become more extensive next week and may
extend onto the lower coastal mountain slopes for the middle of
next week.

&&

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

.Morning Update...
A weak costal eddy formed overnight in the presenece of a weak
trough overhead, leading to extensive low cloud coverage for areas
west of the mountains and clearer skies across higher elevations
into the deserts. Slow clearing is occurring across portions of
the Inland Empire this morning. Most valleys should clear this
morning, but confidence is low to moderate in significant clearing
toward the coast later this afternoon. A similar low cloud
pattern will occur tonight. The windiest day across the mountains
and deserts this week will be today, where a Wind Advisory is in
effect for areas of the San Gorgonio Pass, including along
Interstate 10, so make sure to travel with care this afternoon and
tonight.

Slightly warmer this weekend with warmer weather and less wind. A
closed low will form off the Pacific, leading to cooler and
breezier weather next week.

.Previous Discussion (439 AM Friday)...

.SHORT TERM (Today through Sunday)...
A weak low pressure system centered just west of Point Conception
will move quickly inland across the area today. The marine layer
has deepened to around 3000 feet with low clouds over the coastal
waters extending inland across most of the valleys. There are also
a few high clouds.

There will be stronger onshore flow with gusty southwest to west
winds for the mountains and deserts for this afternoon into
tonight with the stronger gusts to 45 to 55 mph. The strongest
gusts will be in the northern Coachella Valley below the San
Gorgonio Pass with gusts to 65 mph.

High temperatures today will be a few to around 5 degrees cooler
than Thursday for most areas with high temperatures for the coast
and valleys mostly a few to around 5 degrees below average with
the deserts still around 5 degrees above average.

For the weekend, high pressure aloft will bring a warming trend
with the marine layer becoming shallower by Saturday night and
Sunday. Saturday will be a few degrees warmer than Friday at lower
elevations to around 5 degrees warmer for the mountains, then a
few degrees warmer on Sunday for the lower deserts to 5 to 10
degrees warmer for the inland valleys.

With the warming, high temperatures on Sunday will be a few
degrees above average near the coast to 10 to 15 degrees above
average for the deserts, mountains, and inland valleys. High
temperatures on Sunday for the lower deserts will be mostly in the
90s. NBM has a 64 percent chance on Sunday and again on Monday
for Palm Springs to have a high temperature of 100 or higher.

&&

.LONG TERM (Monday through Thursday)...
A low pressure system over the eastern Pacific will eventually
move inland through southern California and northern Baja some
time around the middle of next week. Cooling will begin to spread
inland on Monday with the cooling continuing through Thursday.
With the cooling, high temperatures on Thursday will be around 10
to 15 degrees below average for the mountains and inland valleys.

There do remain model differences on the speed and timing of the
inland movement of the low pressure system around the middle of
next week. This will affect how quickly and when the marine layer
will deepen sufficiently for night and morning coastal low clouds
extend well inland and onto the lower coastal slopes of the
mountains.

&&

.AVIATION...
191520Z...Coast/Valleys...Widespread marine low clouds with bases
near 2000 feet and tops 2800 feet producing MVFR ceilings of 1000 to
2300 feet above ground level. Since the layer is thin there
should be partial burn off in most areas 19 to 22 UTC but a weak
disturbance tracks through Socal near 00 UTC/20 which will affect
the marine layer. The marine layer will fill back inland from 01 to
04 UTC with similar widespread coverage but becoming slightly lower
by 500 feet in the wake and sinking air of the weather disturbance.

Otherwise...SCT cumulus at around 12000 feet over mountains between
19-02Z and SCT clouds at/above 20000 feet MSL with unrestricted VIS
today and tonight. Surface wind increase to 20 knots sustained from
00 to 03 UTC today for the Coachella Valley.

&&

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

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 3 AM PDT Saturday for San Gorgonio Pass Near
     Banning.

PZ...None.

&&

$$

MORNING UPDATE/PREVIOUS PUBLIC...APR/17
AVIATION/MARINE...Tardy