086
FXUS66 KSGX 050536
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
936 PM PST Tue Feb 4 2025

.SYNOPSIS...
A low pressure system to the north will bring cooler and cloudier
weather through Friday. Mostly light precipitation will occur at
times from tonight through Friday night. Drier for the weekend
into early next week, with daytime temperatures near or a little
cooler than seasonal averages.

&&

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

Mostly light precipitation is moving into areas east of Point
Conception this evening, extending as far eastward as Los Angeles
County, though most measurable precipitation is still back in
Ventura County. Based on latest hi-res guidance, showers will
begin to spread into Orange County and western San Bernardino and
Riverside Counties by early Wednesday morning. Only isolated
showers are expected across San Diego County with this first wave
of precipitation. Through Wednesday night, rainfall totals will
range from around one-quarter inch near the LA County border to
only a couple hundredths at most in southern San Diego County. The
favored south slopes of San Bernardino County could get as much
as 0.75-1.00 inch. Overall forcing with this first wave is very
weak, so orographic precipitation will far outdo anything at the
lower elevations.

Another subtle and weak short wave and residual low-level
moisture will maintain a 50-60% chance of precipitation into
Thursday for the mountains westward, though additional
accumulations will generally be less than one-tench inch with only
isolated to scattered coverage of showers. The main trough axis
moves through on Friday, providing better lift for more widespread
and slightly heavier showers Thursday night into Friday morning,
especially for areas further south. Showers will taper off by
Friday night.

Snow levels will remain mostly at or above 7,500 ft into Friday -
briefly lowering to 6500 to 7000 feet for late Wednesday night into
Thursday then again lowering to 5500 to 6000 feet for late Friday
night. Only small accumulations of snow are expected at those
elevations.

Daytime temperatures will remain mostly near or a little below
seasonal averages into early next week, with some day-to-day
variations.

For the weekend into early next week, it will likely be drier
with warmer days and cooler nights with Sunday high temperatures
within a few degrees of average for most areas, in the 60s and
lower 70s for the coast and valleys and in the lower to mid 70s
for the lower deserts. Broad troughing will dominate the pattern
over the western US, though there is the potential for at least a
brief period of offshore flow on Sunday morning as surface high
pressure builds over the Great Basin.

&&

.AVIATION...
050430z...Coast/Valleys...A few cloud decks are present this
evening, with one developing along the mountain foothills, based
around 3000 ft MSL, and another moving in from the northwest ahead a
of a weak weather system, with bases 4000-6000 ft MSL. Low clouds
will continue to become more widespread across the region, generally
remaining above 3000 ft MSL this evening and tonight, but
intermittent CIGS 2500-3000 ft MSL are possible overnight. Spotty -
SHRA will gradually move southeast through the region late this
evening through Wednesday morning, into Orange County and the
northern IE by 09Z and then into northern San Diego County by about
15Z. Scattered MVFR cigs are possible in showers. More isolated -
SHRA will continue to be possible Wednesday, becoming more
widespread again in the late evening. CIGs will trend lower late Wed
evening, with bases 2000-3000 ft MSL.

Mountains/Deserts...Low clouds and fog will continue to become more
widespread this evening along the coastal mountain slopes, leading
to low VIS conditions and terrain obscurement. Chances for -SHRA
increase late tonight for the coastal slopes, continuing through
Wednesday. Dry, VFR conditions continue in the deserts. Locally
breezy south to southwest winds along the mountain slopes into the
desert, with local gusts 25-40 kts, will continue through Wednesday
morning, leading to MOD UDDFS.

&&

.MARINE...
Northwest winds will strengthen Friday afternoon, with gusts around
20 knots possible in the outer coastal waters, before diminishing
early Saturday morning. Otherwise, no hazardous marine conditions
are expected through Saturday. An increasing swell out of the WNW
will lead to seas of 5 to 7 feet early Saturday, especially for the
outer coastal waters and near San Clemente Island.

&&

.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...SS
AVIATION/MARINE...CSP