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000
FXUS66 KSGX 012036
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
136 PM PDT Thu Jun 1 2023

.SYNOPSIS...
A gradual warming trend is in store through the weekend with
high temperatures slightly above average for the deserts, but
remaining below average over/west of the mountains. A deep marine
layer will decrease in depth over the weekend, but with night and
morning coastal low clouds still extending well inland and
covering much of the valleys. A low pressure system from the west
early next week will bring cooling, a deeper marine layer, and a
slight chance of showers and thunderstorms.

&&

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

At 1 PM, mostly cloudy skies continued for all land areas, with
some thinning of the clouds over the waters. Overall, not
expecting much more clearing today for land areas. With the deep
marine layer in place, some drizzle could occur tonight into
Friday morning over/west of the mountains. Not expecting much
accumulation, but if anything accumulates, it would most likely
occur on the coastal mountain slopes.

A weak low will move across northern Baja today and tonight,
maintaining our marine layer and cooler conditions today. The low
will quickly pass east on Friday, with heights building in from
the south Friday through the weekend, bringing us a warming trend
for the weekend. Inland areas will see the greatest warming,
though areas over/west of the mountains will continue to remain
around 5 degrees below average. Desert areas will get to at least
average to a couple of degrees above average, with highs in the
Mojave getting into the low 90s and the Coachella Valley and San
Diego desert getting into the low 100s Saturday and Sunday.

With high pressure building in this weekend, the marine layer will
become shallower, so there`s a decent chance for some of these
low clouds to clear out each afternoon in the valleys. For our
coastal dwellers, the best chance for clouds partially clearing
out will be Saturday afternoon, mostly along the Orange County
coast. Confidence is lower for clearing along the San Diego County
coast this weekend.

As we get into early next week, the pattern certainly turns
interesting for June, with the subtropical jet remaining to our
south and a closed low pressure system pushing near Southern
California from the west. This low looks to go nowhere fast,
remaining over southern or southeastern California for much of
next week. This will increase onshore flow, deepen the marine
layer, and bring cooler conditions for all areas. This could also
bring us shower and thunderstorm activity around the Monday/Tuesday
time frame. There are more ensemble members showing measurable
precipitation for early to mid next week, though the spread in the
ensembles still remain significant. The ECMWF Extreme Forecast
Index shows some ensemble members well outside of climatology for
early June for CAPE Monday and Tuesday in northern areas. So,
there`s a chance for shower and thunderstorm activity sometime
early next week, but exactly where and when remains uncertain. For
now, slight chances for showers and thunderstorms remain in the
forecast for areas north of San Diego County.

&&

.AVIATION...
012000Z...Coasts/Valleys/Coastal Mountain Slopes...BKN-OVC low
clouds with bases 2000-3000 feet MSL and tops to 6000 feet will
continue through tonight. Local cigs down to 1500 feet with patchy
vis 3-5SM. Coastal mountain slopes remaining obscured. Partial
clearing is still possible this afternoon but likely only at the
inland edges of the cloud layer. Clouds filling in again after 23Z
with bases around 1500-2500 feet MSL and tops to around 4000 feet.
Any clearing on Friday will be limited and likely not until after
18Z.

Desert Mountain Slopes/Deserts...Mostly clear with unrestricted vis
through tonight. Areas of west winds with gusts 30-40 kt 00-09Z
Friday with moderate up/downdrafts and LLWS over and east of the
mountains.

&&

.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...None.
PZ...None.

&&

$$

PUBLIC...Connolly
AVIATION/MARINE...PG