Riverside, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

827
FXUS66 KSGX 300423
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
923 PM PDT Tue Apr 29 2025

.SYNOPSIS...
Fair and spring-like weather will prevail this week, with coastal
low clouds and fog during the nights and mornings, along with
breezy afternoons and evenings in parts of the mountains and
deserts. This weekend, a low pressure trough will bring much
cooler, cloudier, and windier weather with some showers. A
gradual warming and drying trend follows next week.

&&

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

Satellite imagery tonight shows marine layer low clouds along much
of the southern California coastline and starting to creep inland.
These will make their way into parts of the inland valleys
overnight, including parts of the Inland Empire. The marine layer
will start to break up and retreat towards the coast again
starting around 8 AM Wednesday morning, and will have mostly
cleared by about 11 AM. A swath of mid to upper level clouds
currently visibly passing through central California will move
into the region from the morning through the late afternoon,
however, preventing completely clear skies. Otherwise, expect
overnight and Wednesday morning temperatures to be a bit warmer
than this morning, with similar afternoon high temperatures to
today. Otherwise, no significant change to the forecast was
needed, and more details about the upcoming week can be found in
the previous discussion below.

PREVIOUS DISCUSSION...Issued 117 PM PDT Tue Apr 29 2025...

We have fair and warmer weather today, accented by some pretty
cumulus clouds over the mountains. We can thank a fleeting ridge
of high pressure aloft for the pleasant spring-like temperatures.
Within the broader longwave ridge pattern is a weak low pressure
trough that develops Wednesday and Thursday right over SoCal. It
will serve to bring cooler weather by a couple degrees, and also
help rebuild the marine layer seemingly into a coastal low cloud
forecast we can count on. And one that spreads coastal low clouds
well inland each night and morning.

There is also some instability over the high desert and San
Bernardino Mountains indicating a remote chance of thunderstorms
Thursday and/or Friday, which we`ll keep an eye on, but as of
today the chance is pretty microscopic. Breezy onshore winds will
increase through mountain passes and into deserts each afternoon
and evening. Isolated pockets, such as through and east of the San
Gorgonio Pass, should get gusts at or above 40 mph. Another
fleeting ridge on Friday brings slightly warmer weather.

Then a big trough develops and deepens as it drops down the coast
arriving in SoCal Saturday. Probably the biggest impact will be
strong winds in all areas, but particularly in the mountains,
deserts and coastal waters. It will also bring cold air,
destabilizing the atmosphere, and not a lot of moisture, but
enough for showers. Thunderstorms are also not out of the question
late Sunday. Snow will fall in the mountains as the snow level
drops quickly on Sunday morning (currently showing down to around
5,000 feet). There won`t be a lot of precipitation, but some.
While confidence is high in the much cooler weather, the winds,
and the showers, confidence is lower in the precipitation amounts.
Confidence is growing in the timing of the winds and
precipitation: Saturday evening through Sunday looks like the
stormiest time. We have less confidence on when the storm departs
on Monday...ish. Tis the season for closed low pressure systems
that separate from the jet stream and give forecasters fits, but
this upcoming system doesn`t look as capricious as usual. It does
move slowly, so next Monday or Tuesday a tepid warming and drying
trend appears to get underway.

&&

.AVIATION...
300400Z....Coasts/Valleys...BKN-OVC clouds with bases 1000-1500 ft
MSL impacting KSAN and KCRQ then KSNA after 06Z. Bases will lower to
around 700 ft MSL between 08Z and 12Z with impacts at all coastal
TAF sites. Bases rise to 1000-1200 ft MSL after 14Z. Low clouds and
fog could extend up to 20 miles inland with about a 60 percent
chance of CIGs and reduced VIS at KONT briefly around 15Z. Vis
restrictions are expected where low clouds intersect higher coastal
terrain. At least partial clearing expected at the coast between 17Z
today and 02Z Thu.

Mountains/Deserts...Mostly clear skies tonight through Wed.

&&

.MARINE...
No hazardous marine conditions are expected through Friday. Gusty
west to northwest winds will develop over the coastal waters this
weekend, with strongest winds Saturday night and Sunday. Peak gusts
of 25 to 30 kt expected. Gale force winds are possible, with a 25
percent chance of winds reaching at least 34 kt in the outer coastal
waters near San Clemente Island Saturday night into Sunday morning.

&&

.BEACHES...
Elevated surf of 3 to 6 feet with sets to 7 feet will occur through
Wednesday. Highest surf occurred on south facing beaches today and
will gradually lower on Wednesday. Strong rip currents are
expected.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Wednesday evening for Orange
     County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...CSP
AVIATION/MARINE...PG