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000
FXUS66 KSGX 121101
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
400 AM PDT Fri Apr 12 2024

.SYNOPSIS...
Today will be a little cooler than yesterday, and be followed be
even greater cooling over the weekend as a trough moves across the
region. This trough will bring gusty winds and light showers at
time. Dry weather if forecast next week.

&&

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

The marine layer was between 1,000 and 1,300 feet deep this morning,
extending to near Chino and Corona in the western Inland Empire, and
to Fallbrook, El Cajon and Ramona in the San Diego County valleys.
The clouds layer was 500-800 ft thick. Clearing today will be
similar to yesterday with the clouds retreating from the valleys
through the morning but lingering near the coast into the afternoon.
The mountains and deserts will be sunny today.

Water vapor imagery showed the center of a compact upper level
circulation 600 miles west of Oregon this morning. This cold core
low will dig south today, and by Saturday morning it will be just
west of SFO. The first of two shortwaves with this trough will track
over Ventura, LA Counties and San Bernardino Counties Saturday
afternoon and evening, bringing a swath of mostly light precipiation
to SoCal during that time. It will first move into the San
Bernardino County Mountains and Orange County, then spread southeast
through the afternoon and evening. Precipitation will be generally
light but with a distinctive north-to-south rainfall gradient. The
highest amounts will be in San Bernardino and Orange County with
lighter amounts in southern San Diego County.

There will be a break in the precipitation Saturday night into
Sunday morning before the second shortwave with a more southerly
trajectory brings a more direct hit to SoCal Sunday afternoon
through Sunday night. Like the first shortwave, this one also
doesn`t have a lot of moisture to work with and the precipitation
amounts will be light. Total rainfall through Sunday night will
range from a few hundredths of an inch to a quarter of an inch in
the coastal and valley areas, from a tenth to a half inch in the
mountains (highest in the San Bernardino Mountains), and less than
0.10" in the high desert.

Snow levels between 5500-6500 feet on Saturday will fall to 4500-
5500 feet Sunday with 2-4" in the San Bernardino Mountains above
6,500 feet.

It will be another cool weekend with gusty winds at times. Sunday
will be the coldest day with highs in the low 60s west of the
mountains, the 30s and 40s in the mountains, and the 50s in the high
deserts. The lower deserts will see highs in the low to mid 70s with
blustery winds and areas of blowing dust and sand at times.

The low moves eastward on Monday with cool, dry northwest flow
through Wednesday keeping temperatures a little below average
through midweek.

&&

.AVIATION...
121000Z...Coast/Valleys...Low clouds will prevail along the coast
and in some valleys this morning with bases 400-1600 ft MSL and tops
to 2000 ft MSL with areas of VIS 2-4 miles in BR, locally below 1
mile in FG/BR, and areas of terrain obscurations. Bases will rise to
mostly 1300-1700 ft MSL after 14Z. Most valleys will clear 15-17Z
but coastal areas will only have partial afternoon clearing. Low
clouds will be widespread tonight and Sat morning with bases 2000-
3000 ft MSL with SCT -SHRA developing Sat morning.

Mountains/Deserts...Mostly clear skies and unrestricted VIS will
prevail through this evening with terrain obscurations developing on
the lower coastal mountain slopes after 10Z Sat. Areas of west winds
with surface gusts 25-35 kt will develop after 21Z and continue
through Sat morning.

&&

.MARINE...
No hazardous marine conditions are expected through Saturday, though
showers will occur Saturday, continuing Sunday. West winds could
locally exceed 20 knots Sunday and Sunday night.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...Moede
AVIATION/MARINE...Maxwell