Villa Park California Weather Forecast Discussion

278
FXUS66 KSGX 100945
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
245 AM PDT Fri Oct 10 2025
.SYNOPSIS...
A low pressure system off the West Coast will continue to draw
moisture from Tropical Storm Priscilla northward into the area
through Saturday morning, with chances for showers and
thunderstorms at times. Cooler with drying and a return of the
marine layer early next week. For Tuesday and Wednesday of next
week, a low pressure system moving southward along the West Coast
will bring a chance of showers along with stronger westerly winds.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
This morning, a band of light showers extends from the coastal
waters near San Clemente island to the high deserts northeast of
Big Bear. The band as a whole is slowly drifting northward even as
the elements move to the northeast in the mean flow around the
base of a trough extending from a low pressure system centered
off the Oregon coast. So far, rainfall amounts have been light,
ranging from a trace to about two tenths inch in the last 12
hours. While the bulk of the moisture from what is still Tropical
Storm Priscilla remains to our east and south, there is no
shortage of moisture over SoCal, with about 1.4 inches of
precipitable moisture. What we seem to lack is a deep, unstable
layer and a mechanism for forcing deep convection. Moisture from
Priscilla will continue to be drawn into SoCal through late
tonight or early Saturday morning, continuing the chances for
showers and tstms. Chances for tstms with locally heavier rainfall
increase over the mtns and deserts late today as Priscilla`s
upper level circulation is drawn into the mean southwesterly flow
becoming an open wave by this afternoon and all but vanishing in
the circulation around the low to the northwest by Sat morning.
Overall, precipitation is not expected to be heavy but locally
heavy rainfall in tstms can`t be ruled out due to the amount of
available moisture.
Fair and cool weather is expected from late Sat through Monday
under cyclonic flow aloft. Onshore flow will strengthen late Sat
into Sun morning as the low moves inland to the north. Winds will
peak Sat evening with localized gusts of up to 50 mph in the
favored mtn passes and adjacent desert areas. The marine layer low
clouds and fog could make a return as soon as Sat morning but more
likely for Sunday and Monday mornings.
For next Tue and Wed...Model solutions begin to diverge on Monday
as a reinforcing shortwave trough moves southward out of western
Canada into the mean trough over the western US. Beyond Monday,
forecast details are uncertain due to significant spread in the
model solutions with respect to the timing and placement of the
low pressure system as it forms a closed upper low near WA/OR on
Monday then moves southward along the coast, reaching SoCal on
Wed. Depending on which solution verifies best, we could be cold,
windy and wet for Tue-Wed or we could be cold, windy and not so
wet. There is a small chance for a dusting of snow on Tue in the
San Bernardino Mtns above 7,500 ft but it`s not something I would
plan on at this point.
The low/trough moves inland toward the end of next week and fair
weather will likely return but the timing remains uncertain.
&&
.AVIATION...
100930Z....BKN clouds based 8000-12000 feet MSL with ISO -SHRA
region-wide today and tonight, and ISO-SCT SHRA/TSRA inland
18-04Z. Any TSRA could lower cloud bases to 5000 feet MSL briefly,
and could bring gusty winds and reduced vis in +RA. Decreasing
clouds and
-SHRA overnight into Saturday, but patchy coastal low clouds based
 around 1000-2000 feet MSL to develop after 08Z into Saturday.
&&
.MARINE...
Northwest wind gusts occasionally exceeding 20 knots around San
Clemente Island during the afternoons and evenings today and
Saturday. No hazardous marine conditions are expected today through
Tuesday.
&&
.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...PG
AVIATION/MARINE...MM

NWS SGX Office Area Forecast Discussion