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879
FXUS66 KSGX 011625
AFDSGX

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

.SYNOPSIS...
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Slightly cooler high temperatures today compared to yesterday. The
deep marine layer today, will get shallower for Thursday and
Friday with warming conditions. A passing low pressure system
will bring increased cloud coverage, cooler conditions, periods of
gusty westerly winds, and a slight chance of precipitation to the
area over the weekend. Drier and warmer conditions expected early
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 deep marine layer overnight brought low clouds and fog
to the coastal mountain slopes, locally filling in mountain
passes. Areas of drizzle and even light rain were reported. Rain
accumulations were mostly confined to the mountain foothills,
although a few valley locations picked up a hundredth of an inch.
At 9 AM, low clouds were beginning the process of scattering out.
Most areas will see some sunshine today. A coastal eddy is
expected remain present through at least Saturday, which will
help maintain areas of night and morning low clouds and fog. Even
with the eddy the marine layer is expected to get shallower
tonight and Friday night. Low clouds and fog are forecast to reach
into the valleys, but are not expected to completely fill in the
coastal basin.

High temperatures today are expected to be a few degrees cooler than
yesterday for most areas. A few degrees of warming is expected for
Thursday with another warm day expected on Friday. On Saturday, an
incoming low pressure system is expected to push the weak ridge over
us to the east. This will bring a few degrees of cooling for
Saturday, with even more cooling on Sunday as the low digs into
the Great Basin. Highs on Sunday are expected to be 5 to 10
degrees cooler than Saturday west of the mountains and 10 to 15
degrees cooler than Saturday in the mountains and deserts. Monday
and Tuesday are expected to be warmer, but highs will still be
below average on Tuesday.

The passing low will increase the onshore pressure gradient over the
weekend which will enhance westerly winds over the mountains,
through passes, and into the deserts. Winds are expected to peak
late Saturday into Sunday afternoon. Winds will slowly decrease
Sunday night into Monday.

The passing low will dig far enough south to bring chances of
precipitation to Southern California mainly Saturday night into
Sunday morning. 24-hour chances for measurable rainfall are
around 20 percent for the mountains and around 10 percent near the
coast. Rainfall is expected to be mostly light and confined to
areas in and west of the mountains. Chances for one-quarter inch
or more of rainfall in the mountains are around 10 percent with a
10-30 percent chance of the coast and valleys accumulating a tenth
of an inch or more. Dry conditions are expected to return by
Monday.
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&&

.AVIATION... 
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011600Z...Coasts/Valleys/Coastal Slopes...Low clouds
with bases 1800-3000 feet MSL will continue to dissipate by 18-19Z.
Low clouds redeveloping at the coast and spreading inland after 03Z,
with bases 1500-2500 feet MSL, spreading into portions of inland
valleys by Thursday morning. Scatter out Thursday by 15-17Z.

Otherwise, mostly clear skies with unrestricted vis through Thursday
morning.
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&&

.MARINE...
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No hazardous marine conditions are expected through Friday. Gusty
northwest winds late Saturday and Sunday could generate hazardous
boating conditions.
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&&

.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...CO
AVIATION/MARINE...MM