205
FXUS66 KSGX 232146
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
146 PM PST Sat Nov 23 2024

.SYNOPSIS...
Below average temperatures are expected west of the mountains today,
with chances of showers this afternoon and overnight. Rain chances
will move from northwest to southeast, starting in Orange County and
southwestern San Bernardino County this afternoon and ending in San
Diego county by Sunday morning. The rest of Sunday is expected to
remain dry, with additional chances of precipitation Monday through
Wednesday. Periods of gusty westerly winds for the mountains and
deserts are expected tonight into Sunday and again Tuesday into
Wednesday. Dry conditions are expected for the Thanksgiving
holiday.

&&

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

A few light showers had made it to the LA/Orange County line as of
1:30 PM. Showers are expected to become more widespread and spread
southeast into San Diego county overnight. As far as forecast
rainfall totals go, most low elevation areas will see a tenth of an
inch or less, with Orange County and the Inland Empire the most
likely place to see totals closer to a tenth of an inch. Orographic
effects are expected to bring higher rainfall totals to the coastal
slopes of the mountains, particularly the San Bernardino Mountains.
Forecast totals range from 0.10-0.35 inches, locally up to 0.75 inch
in the San Bernardino county mountains. For the San Diego and
Riverside mountains, rainfall totals will be 0.10-0.25 inches.

Gusty west winds will continue over the mountains and into the
deserts. Winds will peak in strength late tonight into early Sunday.
Peak gusts of 30 to 45 mph expected. Winds will weaken by Sunday
afternoon. Snow levels will remain near or above 7000 ft through
Sunday. Only minor snow accumulations are expected.

Another moisture surge is expected for early to mid next week.
Periods of rain are possible as early as Monday for Orange County,
portions of the Inland Empire, San Bernardino mountains, and High
Desert. Wetter conditions are expected to spread south into San
Diego County sometime Tuesday into Wednesday. Most ensemble members
for both the ECMWF and GEFS are showing light to moderate
precipitation for areas north of San Diego County, with the trend
towards lighter amounts for San Diego County. In addition to periods
of rain, gusty westerly winds are again expected for the mountains
and deserts. Snow levels are expected to remain 7000 ft and above.
Temperatures are expected to remain near to slightly below average
for areas west of the mountains through the middle of the week.

Dry conditions are expected for Thursday and much of Friday. By
Saturday, there becomes some disagreement in model solutions. About
55 percent of ensemble solutions show ridging over California and
drier conditions, with 45 percent showing weak troughing and wetter
conditions for Saturday. The forecast for late Friday into next
Saturday follows the NBM with slight (15 to 20 percent) chances of
precipitation in and west of the mountains. The alternative to the
current forecast is warmer and dry conditions.

&&

.AVIATION...
232100Z...Coast/Valleys...Satellite shows low clouds have cleared
out along the coast but mid to high clouds continue to push down
ahead of an atmospheric river, which will overspread much of the
region by this afternoon/evening. Sct-BKN bases will vary between
7,000-10,000ft MSL and 15,000-20,000ft MSL, increasing to BKN-OVC
tonight. Low clouds return by 22Z Sat-02Z Sun in all coastal/valley
areas with bases 1200-2000 ft MSL and tops 4000-7000 ft MSL and with
areas of terrain obscurations in clouds/-SHRA. Local VIS 3-5 miles
will occur in -SHRA mainly 00Z-12Z Sun. Most areas will clear 18-20Z
Sunday, but mid to high clouds will prevail through Sunday evening.

Mountains...Periods of gusty winds near mountain peaks and mountain
passes this evening and tonight with gusts up to 30 mph. Areas of
terrain obscurations will occur 22Z Sat-08Z Sun in the San
Bernardino County/Riverside County mountains and 01Z-12Z Sun in the
San Diego County mountains due to clouds/FG/-SHRA, especially on the
coastal slopes, with cloud tops mostly to around 10,000ft MSL. Mid
level cloud cover with SCT-OVC will prevail for most of Sunday.

Deserts...Unrestricted VIS will prevail through this afternoon with
FEW-SCT high clouds with bases near 25,000ft MSL. Increasing cloud
cover tonight ahead of an atmospheric river will bring FEW-SCT mid
to high clouds with bases 10,000-12,000ft MSL, becoming SCT-BKN by
Sunday morning with similar bases. Brief periods of gusty winds up
to 20 mph possible 00z-14z.

&&

.MARINE...
No hazardous marine weather is 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...CO
AVIATION/MARINE...Zuber