000
FXUS66 KSGX 231020
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
320 AM PDT Tue Apr 23 2024

.SYNOPSIS...
A cooling trend will continue through Thursday with periods of
stronger and gusty southwest to west winds continuing for the
mountains and deserts into Friday evening. A deep marine layer
will continue into Friday with some light precipitation from
drizzle or light rain possible from the coast to the coastal
slopes of the mountains, mostly during nights and mornings. Then
warmer and drier with weaker winds for Saturday through Monday
with Sunday high temperatures around average and Monday high
temperatures around 5 degrees above average.

&&

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

.SHORT TERM (Today through Thursday)...
A low pressure system to the west of the area will move inland
through southern California on late Wednesday and Wednesday night
with stronger onshore flow continuing into Friday night as a
second low pressure system from the northwest moves through
southern California some time around Friday.

The marine layer has deepened to around 4000 feet with an
extensive low cloud field over the coastal waters extending inland
across all of the valleys and onto the lower coastal slopes of the
mountains. There were areas of drizzle late Monday evening as the
depth of the saturated cloud layer increased to around 2500 feet
versus around 800 feet late Monday afternoon. The greatest
concentration of light measurable amounts has been over the
western valleys in San Diego County and for inland Orange County
onto the coastal slopes of the Santa Ana Mountains. This deep
marine layer will continue into Friday with chances for measurable
precipitation from drizzle or light rain, mainly during the
nights and mornings.

Periods of gusty southwest to west winds will continue for the
mountains and deserts into Friday evening with the stronger winds
along and below the desert slopes of the mountains in Riverside
and San Diego Counties. ECMWF ensemble output shows the winds
gradually increasing each day into Friday with the strongest winds
on Friday afternoon. With the gradual strengthening, the winds
could be strong enough for a Wind Advisory as early as Wednesday
afternoon and evening.

High temperatures for inland areas will cool each day through
Thursday with Thursday high temperatures around 5 degrees below
average near the coast to 10 to 15 degrees below average for the
mountains and valleys.

&&

.LONG TERM (Friday through Monday)...
After Friday, there will be warming and drying for Saturday
through Monday with weaker winds. High temperatures will warm each
day to around average on Sunday and around 5 degrees above average
on Monday.

&&

.AVIATION...
230930Z...Coast/Valleys/Foothills...Low clouds with bases 1500-2500
feet MSL, locally down to 1000 feet in -DZ, and tops to 4000 feet.
VIS 0-5SM inland, where clouds and terrain intersect obscuring
foothills. Expect inland clearing 17-19Z with only partial clearing
in the coastal areas. CIGs around 2000-3000 feet could impact
coastal airports through afternoon. Low clouds to push inland and
fill the coastal basin to foothills again after 01Z into early
Wednesday. Similar bases and inland vis reductions.

Mountains/Deserts...Mostly clear skies (above 4000 feet MSL on
coastal slopes) with unrestricted VIS today and tonight.

&&

.MARINE...
No hazardous marine conditions are expected through Thursday.
Stronger northwest winds and choppy seas arrive late Thursday and
continue into early Saturday, likely generating hazardous conditions
at times, especially in the outer waters.

&&

.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