San Diego Forecast Discussion
883
FXUS66 KSGX 140441
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
930 PM PDT Fri Sep 13 2024
.SYNOPSIS...
High temperatures will remain about 5 to 10 degrees below average
through the weekend, with night and morning coastal low clouds
extending inland to the valleys and foothills. A stronger low
pressure system moving inland through central California will
deepen the marine layer late Sunday night and Monday, with a
slight chance of light precipitation from the coast to the
mountains. This will bring additional cooling, with high
temperatures as much as 15 to 20 degrees below average in inland
areas Monday. High temperatures will increase a few degrees
Tuesday, but remain well below average through next week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Update...
Stratus covered most coastal areas and was spreading rapidly into
the valleys at mid-evening. Elsewhere, skies were clear except where
smoke was occurring near the 3 large wildfires in SoCal. The stratus
should cover all areas west of the mountains by late tonight.
Otherwise, daily high temperatures will continue to lower a bit in
most areas each day through Sunday, then drop more substantially
Monday as that deep closed low moves into central California where
the trough was already in existence. The marine layer moisture will
have had several days to get established by Monday, so at least some
precipitation should occur, especially on the lower orographic
southwest facing mountain slopes. How high up the mountain that the
precip goes will depend on the marine layer depth, which looks like
it will be in the 5000-6000 foot range at least in San Bernardino
County (less in San Diego County). Most precipitation amounts should
be 1/10 inch or less, except possibly a little more on best
orographic slopes.
From previous discussion...
Onshore flow will continue through the weekend, with a marine
layer around 3500 feet deep and low clouds extending inland
to the lower coastal slopes during the nights and mornings. High
temperatures will remain around 5 degrees below average to locally
10 degrees below average for the western valleys and inland
Orange County. High temperatures near the coast will be in the
lower 70s with high temperatures for the inland valleys mostly in
the 80s.
A stronger low pressure system moving inland through central
California will strengthen the onshore flow, deepen the marine
layer and bring colder air into SoCal Sunday night into Monday.
Coastal low clouds will extend onto the coastal slopes of the
mountains with a light chance for light precipitation late Sunday
night into Monday morning from the coast to the mountains.
High temperatures on Monday will be several degrees cooler for
inland areas, with high temperatures for the mountains, valleys,
and high desert around 15 to 20 degrees below average. High
temperatures on Monday for the inland valleys will be mostly in
the 70s, mostly in the 50s and lower 60s for the mountains, and in
the 80s for the lower deserts.
There will be stronger southwest to west winds for the mountains
and deserts late Sunday into Monday with gusts 30 to 40 mph.
Stronger winds are expected in the northern Coachella Valley below
the San Gorgonio Pass with gusts locally 60 to 70 mph.
High temperatures will be a few degrees warmer on Tuesday, but
remain well below average through Thursday. Another low pressure
system from the northwest will move through California some time
around late Wednesday into Thursday, with another slight chance
of light precipitation from the coast to the mountains.
This could be followed by significant warming for the weekend of
the 21st and 22nd, with high temperatures increasing to near or
slightly above average. The greatest model spread in the amount of
warming for that Friday through Sunday is for the valleys.
&&
.AVIATION...
140430Z...Coasts/Valleys...Stratus will continue to spread inland
overnight and cover most coastal/valley areas by 09Z Sat. BKN/OVC
bases will be 1800-2400 ft MSL with tops to 3200 ft MSL, with higher
terrain obscured at times. Most VIS below the cloud bases will be 6+
miles, with only local VIS 3-5 miles in BR, or in the Inland Empire
due to local FU. Most valleys will clear 15Z-17Z Sat, and most
coastal areas will clear 17Z-20Z Sat, with local stratus lingering
near the beach through Sat afternoon. Stratus will rapidly spread
inland again Sat evening.
Mountains/Deserts...Local VIS restrictions will continue through Sat
evening due to FU over the San Bernardino County Mountains near the
Line Fire and Bridge Fire and the Santa Ana Mountains near the
Airport Fire. Otherwise, mostly clear skies with unrestricted VIS
will prevail through Sat evening.
&&
.MARINE...
Stronger winds will occur in the outer coastal waters Monday and
Monday night with gusts 20-25 knots likely from the W/NW. Otherwise,
no hazardous marine conditions are expected through Wednesday.
&&
.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...Maxwell (Update)/PG (Previous Discussion)
AVIATION/MARINE...Maxwell
NWS SGX Office Area Forecast Discussion
