Rancho Cucamonga, California Weather Forecast Discussion

587
FXUS66 KSGX 031027
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
327 AM PDT Fri Oct 3 2025
.SYNOPSIS...
Cooler and breezy today with southwest to west winds for the
mountains and deserts for this afternoon and evening gusting to 35
to 45 mph with gusts to 65 mph in the northern Coachella Valley
below the San Gorgonio Pass. A few degrees of warming for the
weekend, slightly cooler on Monday, then slow warming through
Wednesday and Thursday with high temperatures remaining a few
degrees below average for the middle of next week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (Today through Sunday)...
A low pressure system will move inland into California today and
into Nevada on Saturday. There will be stronger onshore flow for
southern California for today with the marine layer deepening into
tonight. For this afternoon and evening, southwest winds for the
deserts onto the desert slopes of the mountains will gust to 35 to
45 mph with gusts to 65 mph in the northern Coachella Valley below
the San Gorgonio Pass. The marine layer will continue to deepen
into tonight. However, the strength of the marine inversion is
still fairly weak and coverage of low clouds over the coast and
valleys early this morning is quite patchy with greater coverage
over the coastal waters.
Lower level flow will turn briefly northerly on Saturday morning,
then turn back onshore in the afternoon. High temperatures for
inland areas will be much cooler today, as much as 5 to 10 degrees
cooler for the mountains and high desert. High temperatures for
today will range from around 70 near the coast to the mid 70s to
lower 80s for the Inland Empire with the lower deserts in the
lower 90s. Slowly warmer for the weekend with warming of a few
degrees.
&&
.LONG TERM (Monday through Thursday)...
Low pressure from the north may bring slightly cooling on Monday
followed by gradual warming into Wednesday and Thursday with high
temperatures remaining a few degrees below average for the middle
of next week. High temperatures for Wednesday and Thursday will
range from the lower 70s near the coast to the lower to mid 80s
for the Inland Empire with the lower to mid 90s for the lower
deserts. Toward the end of next week, low pressure in the vicinity
of the California coast may draw tropical moisture northward into
the southwest states with more clouds for southwestern California
and a slight chance of showers.
&&
.AVIATION...
031000Z....Coasts/Valleys...Scattered low clouds based 1500-2000 ft
MSL currently over coasts and valleys up to 20 miles inland.
Coverage increasing over the next few hours. 60-70% chance cigs push
into KONT after 12Z. Clouds scatter for inland areas 15-18Z (latest
for areas vcnty KONT), then for coastal areas 17-19Z, though
isolated patches of low clouds could linger along the coast through
20Z. Breezy west to northwest winds expected Friday afternoon, with
gusts to around 20 kts through around 02Z Saturday. Low clouds will
reform in patches after 4/00Z with bases mostly above 2000 ft MSL.
Clouds initially form in San Diego County foothills/valleys, then
spreading north overnight, but remain patchy everywhere.
Mountains/Deserts...Mostly clear and VFR conditions through Friday
night. Stronger winds out of the west pick up and become more
widespread after 18Z Fri through the late afternoon, especially for
deserts and desert foothills, with gusts generally 25-35 kts except
for typically windy spots gusting to around 45 kts. Winds slowly
diminish after 06Z Saturday.
&&
.MARINE...
Northwest winds Friday afternoon and evening over the outer waters
will lead to hazardous conditions for small craft. Expecting
sustained winds 20 to 25 kts and choppy seas 5 to 8 feet. Winds will
be strongest in the vicinity of San Clemente Island. Winds weaken
late Friday evening. No hazardous marine conditions are expected
Saturday through Monday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 11 AM this morning to 11 PM PDT this evening
     for Apple and Lucerne Valleys.
Wind Advisory from 4 PM this afternoon to 5 AM PDT Saturday for
     San Diego County Deserts.
Wind Advisory from 6 AM this morning to 5 AM PDT Saturday for
     San Gorgonio Pass near Banning.
PZ...Small Craft Advisory from 11 AM this morning to 11 PM PDT this
     evening for Waters from San Mateo Point to the Mexican
     Border Extending 10 to 60 nm out including San Clemente
     Island.
&&
$$
PUBLIC...17
AVIATION/MARINE...KW

NWS SGX Office Area Forecast Discussion