Westminster, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

882
FXUS66 KSGX 140400
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
839 PM PDT Sun Apr 13 2025

.SYNOPSIS...
Minor cooling Monday followed by more significant cooling for the
second half of the week, with daytime temperatures down to 10-20
degrees below normal on Friday. Low clouds and fog will continue
across the coastal areas and western valleys each night and
morning through the middle of the week, with marine layer drizzle
possible Tuesday morning. There is a 10 to 15 percent chance of
light precipitation over the mountains Monday night, and then a 15
to 30 percent chance for the mountains westward at times Thursday
night through Saturday.

&&

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

This evening...Surface pressure gradients have trended much weaker
onshore which, along with a weaker inversion, could explain why
today cleared better at the coast than yesterday. Low clouds are
forming along the coast but the coverage and inland extent is
significantly less than at this time yesterday. The afternoon
sounding shows the marine layer deeper than yesterday afternoon
and high-resolution models, however still show marine layer low
clouds extending into the inland valleys by sunrise Monday.

From previous forecast...
Temperatures hold fairly steady for tomorrow with weak ridging
building in and highs generally near normal to slightly above
normal west of the mountains, and 5-10 degrees above normal for
areas east of the mountains. AM low clouds and fog are once again
expected on Monday with similar inland extent and visibility
restrictions as seen this morning. After Monday, a cooler trend
sets in as a series of lows move across the region along with
increasing moisture in the lower and mid levels. For early week, a
low off the coast of San Diego will become an open trough,
sweeping across Baja and up through Southern California, bringing
the first chance for some precipitation early Tuesday morning. At
this time, chances remain low for meaningful precipitation outside
of the mountains where about a 10-20% of some light rain and/or
snow showers will be possible at the highest elevations given snow
levels above 8000ft. Elsewhere, a deepening marine layer may lead
to some morning drizzle, especially for the coastal and valley
areas. As the trough moves up and out on Tuesday the cooler
weather arrives, with highs 5-10 degrees below normal west of the
mountains and slightly above normal for the deserts.

On Wednesday, a low off the coast will begin to push across Central
California, transitioning to a positively tilted trough on
Thursday. This trough will bring significantly cooler
temperatures, 15-20 degrees below normal for some spots, as well
as push some moisture into the area. At the same time, a deep low
pushes down from the north, arriving in southern Nevada by early
Friday morning. Models are in much better agreement today on this
next low, with better agreement on precipitation chances for late
week. Lows both Thursday and Friday in the low to mid 60s along
the coast and in the valleys, 40s and 50s in the mountains, and
60s to low 80s in the deserts. Snow levels will fall to around
6000-6500ft for both days, paving the way for some light snow
accumulations in the mountains. While models are in better
alignment with the upper level pattern for late week, QPF amounts
have generally trended down with the latest model runs, indicating
a higher-confidence in a lower-impact event at this point. Quite
a few things still need to be ironed out with the upcoming system
and how far south it manages to go, but currently the highest
chances (25-35%) for accumulations will be in the mountains. As
the low moves out of the area, a slow warming trend sets in with
weak ridging building and highs look to return to near or slightly
below normal by early next week.

&&

.AVIATION...
140400Z...Coasts/Valleys...Low clouds based 1200-1700 ft MSL are
starting to slowly fill in but remain fairly patchy at this hour
after some efficient clearing that occurred this afternoon. Still,
expecting clouds to continue fill in across the coastal basin over
the next few hours, bringing CIGs to all coastal TAF sites
(KSAN/KCRQ/KSNA) by 05-06z. With tops near 2500-3000ft MSL, clouds
will continue to spread inland overnight, eventually reaching the
Inland Empire and KONT/KSBD by 10/11z. VIS reductions limited to the
higher elevations and localized inland valleys. Low clouds scatter
out in the inland valleys first after 15-16z, with the coasts
clearing out by 18-19z Monday.

Elsewhere...Mostly clear skies with VFR conditions. Local west wind
gusts 25-35 kt over the mountains into the passes and deserts this
evening, waning by 08-09z.

&&

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

&&

.BEACHES...
Surf 3-5 feet is expected through Sunday with sets to 6 feet along
west facing beaches, bringing a high risk for rip currents.

&&

.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/BEACHES...Munyan