Moreno Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

480
FXUS66 KSGX 151024
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
224 AM PST Mon Dec 15 2025

.SYNOPSIS...
Patchy dense fog is expected on the coastal mesas and western
valleys this morning. High pressure and weak offshore flow will
continue to bring fair weather and above normal temperatures
through Friday, with cooler weather this weekend. Coastal low clouds
and fog will continue each night and morning, but less so Tuesday
through Thursday with more coverage Friday through the weekend.

&&

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

With a slightly deeper marine layer this morning, the dense fog is
not as widespread as it has been previously. Still, pockets of
dense fog can be expected on higher coastal mesas and western
valleys this morning, so be aware and plan accordingly, especially
if you travel on the 91 or 241 in OC into Riverside County or the
15 in San Diego County. Otherwise, look for another sunny and warm
day, especially away from the coast. Offshore flow will increase a
little today, producing localized northeast winds through Tuesday
morning in the usual foothill areas through and below mountain
passes. Isolated top gusts could reach 30-40 mph. This offshore
flow will push back on the marine layer, reducing coverage of
coastal clouds and fog for tonight and Tuesday morning. Our large
scale weather pattern features a strong, active zonal flow, which
has brought and will bring heavy rain to WA, OR. The next
shortwave through that region will help turn flow here in SoCal
briefly onshore Tuesday night and Wednesday, bringing back more
coastal fog and also briefly boosting winds in the mountains and
deserts, particularly the high desert late Wednesday. The flow
trends offshore again Wednesday night and Thursday before turning
weakly onshore again Friday. This time the onshore flow appears to
remain for the weekend and beyond, with coastal clouds probably
reaching into some valleys nights and mornings. Temperatures will
fluctuate, especially west of the mountains, as the surface flow
oscillates from onshore to offshore and back again. Right now
Tuesday and Thursday look like the warmest days in the coming
week, with high temps inland reaching 15-20 degrees above average
for this time of year, and 5-10 degrees above average at the
coast. Even the cooler days this week will continue well above
average regionwide. That zonal jet stream to our north will slowly
but steadily sag southward next week, tapping into some
subtropical moisture along the way. Confidence is understandably
low in any forecast that far out, but if the majority of current
ensemble solutions are right, SoCal would get some rain by the
time Santa Claus arrives.

&&

.AVIATION...
150930Z...Coast/Valleys...Low clouds based 300-800 feet MSL have
pushed into inland Orange County and into the valleys of SD County.
BR/FG reducing VIS to 0-2SM for these inland areas, elevated coastal
terrain and the Chino Valley. Patchy BR reducing VIS 1-4SM at the
immediate coast, with periods of VIS below 1SM after 10z. With
offshore flow locally this morning, clouds begin to scatter and VIS
to improve 15-17z in some areas with full clearing to the coast not
until 18-20z. Low clouds with bases 200-600 ft MSL and FG slowly
develop and begin pushing up to 10 miles inland from the beaches 00-
02z Tue, in very patchy fashion. Areas of BR to lower VIS 2-5SM and
patchy FG to reduce VIS to 1/4SM locally.


Mountains/Deserts...Clear skies and VFR conditions expected through
Tuesday morning with FEW high clouds late Monday.

&&

.MARINE...
Low clouds will bring areas of low visibility around 2-5 nautical
miles through early Monday afternoon. Seas rise briefly to 5 to 7
feet in the outer waters Wednesday afternoon through late Thursday.
Otherwise, no hazardous marine conditions are expected through
Friday.

&&

.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...MM
AVIATION/MARINE...Westerink