000
FXUS66 KSGX 261120
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
420 AM PDT Tue Sep 26 2023
.SYNOPSIS...
High pressure to the south will bring warming into Wednesday with
high temperatures a few degrees above average for the lower
deserts and still a few degrees below average for the coast and
valleys. Onshore flow will begin to strengthen on Thursday with a
large low pressure system strengthening over the western states
through the weekend. The weekend will be much cooler, as much as
15 to 20 degrees below average for the mountains and inland
valleys. The marine layer will deepen onto the coastal slopes of the
mountains for the weekend with drizzle or light showers possible
during the nights and mornings for the coast to the coastal slopes
of the mountains and a slight chance for afternoon and evening
showers, mostly near the mountains. There will be stronger and
gusty southwest to west winds for the mountains and deserts for
Friday through Sunday with the strongest winds on Saturday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (Today through Thursday)...
High pressure to the south will bringing warming today and slight
warming on Wednesday with high temperatures in the lower deserts
warming to a few degrees above average and remaining a few
degrees below average for the coast and valleys. A low pressure
system moving inland through the Pacific Northwest on Wednesday
will strengthen the onshore flow across southern California on
Wednesday night and Thursday. This will bring cooling on Thursday
with high temperatures a few to around 5 degrees cooler than
Wednesday.
Night and morning coastal low clouds will remain fairly patchy
into Wednesday morning with the greatest coverage near central and
southern portions of the San Diego County coast. A coastal eddy
for Wednesday night into Thursday will bring greater coverage of
low clouds for coastal areas with the low clouds spreading
northward into Orange County.
&&
.LONG TERM (Friday through Monday)...
A low pressure system will strengthen over the western states
bringing cooling for southern California through the weekend. High
temperatures for Sunday will be around 15 to 20 degrees below
average for the mountains and inland valleys and only reaching the
lower 80s in the lower deserts.
The marine layer will deepen onto the coastal slopes of the
mountains for the weekend with drizzle or light showers possible
during the nights and mornings for the coast to the coastal slopes
of the mountains and a slight chance for afternoon and evening
showers, mostly near the mountains.
Stronger onshore flow will bring stronger and gusty southwest to
west winds for the mountains and deserts for Friday through Sunday
with the strongest winds on Saturday. ECMWF ensemble output has
the strongest winds late Saturday afternoon and has trended
stronger with the winds.
On Monday, the low pressure system will begin to weaken with a
warming trend for Monday into the middle of next week.
&&
.AVIATION...
260930Z...Coast/western valleys...Areas of low clouds will continue
to form with bases around 1200 feet MSL and tops to 1600 feet, more
likely in San Diego County. Local vis on inland extent of clouds
reduced to 3-5SM. Scatter out by 17Z. Low clouds with similar bases
to redevelop after 02Z and gradually increase in coastal areas
overnight into Wednesday. Otherwise mostly clear today and tonight.
Inland Valleys/Mountains/Deserts...Mostly clear skies today and
tonight.
&&
.MARINE...
No hazardous marine conditions are expected through Saturday.
&&
.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...17
AVIATION/MARINE...MM
NWS SGX Office Area Forecast Discussion