618
FXUS66 KSGX 011001
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
301 AM PDT Wed May 1 2024

.SYNOPSIS...
The marine layer has deepened with widespread coastal low clouds
extending inland across all of the valleys. The marine layer will
become shallower for Thursday and Friday with night and morning
coastal low clouds only extending inland across portions of the
valleys. High temperatures for the coast and valleys will be a few
to around 5 degrees cooler than Tuesday, then will be warmer and
similar to those on Tuesday for Thursday and Friday. A low
pressure system moving inland through southern California late
Saturday and Sunday will bring cooling on Saturday and more
significant cooling on Sunday with high temperatures for the
mountains around 15 degrees below average on Sunday. There will be
periods of stronger and gusty southwest to west winds for the
mountains and deserts for late Saturday through Sunday. There is
also a slight chance of mostly light precipitation from the coast
to the mountains for late Saturday night into Sunday. Then drier
and warmer for Monday and Tuesday, but with Tuesday high
temperatures still below average.

&&

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

.SHORT TERM (Today through Friday)...
There is a well-defined coastal eddy early this morning. The
marine layer has deepened to around 3000 to 3500 feet with
widespread coastal low clouds extending inland across all of the
valleys and onto the lowest coastal mountain slopes. Cloud bases
have also risen too, to around 2000 feet near the coast.

There could be some patchy drizzle early this morning, but there
have been only a few locations so far that have received 0.01
inch of precipitation in the valleys. High temperatures today will
be a few degrees cooler than Tuesday with the greatest cooling in
the valleys.

The marine layer will become shallower for Thursday and Friday
with coastal low clouds extending inland only into portions of the
valleys. High temperatures on Thursday and Friday will be a few
degrees warmer than today and similar to those on Tuesday, mostly
a few to around 5 degrees above average.

&&

.LONG TERM (Saturday through Tuesday)...
There has been a narrowing in the model spread in both the timing
and amplitude of the low pressure system moving inland through
southern California for late Saturday and Sunday. The strongest
onshore flow is expected for late Saturday through Sunday
afternoon with gusty southwest to west winds in the mountains and
deserts gradually decreasing for Sunday night into Monday.

High temperatures will be a few to around 5 degrees cooler on
Saturday, mostly within a few degrees of average. There will be
much greater cooling on Sunday with the mountains as much as 15
degrees cooler than Saturday with high temperatures on Sunday
ranging from around 5 degrees below average near the coast to
around 15 degrees below average for the mountains.

Chances for precipitation are greatest for late Saturday night
into Sunday with 24-hour chances for measurable rainfall around 20
percent for the mountains and around 10 percent near the coast
with chances for one-quarter inch or more of rainfall for the
mountains around 10 percent.

Monday and Tuesday are expected to be drier and warmer, but with
high temperatures still below average on Tuesday.

&&

AVIATION...
010935Z...Coasts/Valleys/Coastal Slopes...Low clouds with bases 1800-
2500 FT MSL are occurring this morning. Vis restrictions where low
clouds and terrain intersect. Scatter out 15-17z Wed across inland
areas and 17-19z Wed at the coast. Low clouds redeveloping at the
coast and spreading inland after 01z Thu, with bases 1500-2000 FT
MSL.

Otherwise, clear skies with unrestricted vis through tonight.

&&

.MARINE...
No hazardous marine conditions are expected through Friday. Gusty
northwest winds will develop Saturday into Sunday.

&&

.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...EA