Norco, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

010
FXUS66 KSGX 161121
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
421 AM PDT Wed Apr 16 2025

.SYNOPSIS...
A deeper marine layer along with cooling will continue into
Friday with areas of gusty southwest to west winds for the
mountains and deserts for this afternoon through Thursday night
with the stronger gusts to 40 to 50 mph with isolated gusts to 55
to 65 mph. A pair of low pressure systems, one from the west and
then one from the north will bring chances for showers for late
tonight into Thursday morning and again for Thursday night into
Friday evening. Then dry and warmer for the weekend into early
next week.

&&

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

.SHORT TERM (Today through Friday)...
The marine layer has deepened to 4500 to 5000 feet with coastal low
clouds extending onto the coastal mountain slopes. While cloud
bases are fairly high, there could still be some patchy drizzle
this morning with the 06Z GFS MOS trending a little higher with
chances for measurable precipitation for the coast into the
valleys, but still below 20 percent.

The cooling trend will continue for today and Thursday with not
much change on Friday. High temperatures on Thursday with be as
much as 15 to 20 degrees below average for the mountains and
inland valleys, mostly in the upper 50s to mid 60s for the coast
and valleys and only in the 70s and lower 80s for the lower
deserts.

A low pressure system from the west will be weakening as it moves
through southern California bringing a chance for showers for
late tonight into Thursday morning. A second low pressure system
from the north will bring a chance of showers for Thursday night
and Friday into Friday evening with a slight inland shift to the
track of that system.

Through Friday evening, rainfall and liquid-equivalent above the
snow level could range from less than one-tenth inch near the
coast to one-quarter to one-half inch in the mountains with
locally greater amounts. The snow level will fall to around 6500
feet on Friday with an inch or two of snowfall possible above 7000
feet.

There will be periods of stronger and gusty southwest to west
winds for the mountains and deserts for this afternoon through
Thursday night with the stronger gusts to 40 to 50 mph with
isolated gusts to 55 to 65 mph.

&&

.LONG TERM (Saturday through Tuesday)...
Dry weather is expected with warming for Saturday and Sunday,
continuing into early next week for inland areas while the coast
and valleys may cool slightly for early next week. With the
warming, high temperatures on Sunday will range from the mid to
upper 60s near the coast to the mid 70s to lower 80s for the
Inland Empire with the lower deserts around 90. Overall, high
temperatures will mostly be within around 5 degrees of average for
Saturday through Tuesday.

&&

.AVIATION...
160930Z....Coasts/Valleys/Foothills...Low clouds fill the coastal
basin into the coastal mountain slopes. Bases vary between 2500-3500
feet MSL, with tops to 4500 feet, and vis reductions in hills where
clouds intersect terrain. Patchy -DZ and intermittent cigs down to
2000 feet can be expected through 17Z. Scatter out will be random
and intermittent this afternoon, but with cloud bases mostly above
3000 feet MSL. Low clouds with similar bases/vis to fill the coastal
basin after 02Z tonight into Thursday, again with occasional lower
cigs and vis in -DZ.

Higher Mountains/Deserts...BKN high clouds this morning becoming
SCT for most of the day and tonight. Westerly winds to gradually
increase after 20Z, with strongest gusts 45-55 knots through
pockets of mountain passes and into deserts. Strong up/downdrafts
and isolated LLWS in lee of mountains such as vcnty KPSP.

&&

.MARINE...
No hazardous marine conditions are expected through Sunday.

&&

.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...17
AVIATION/MARINE...MM