Winchester, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

780
FXUS66 KSGX 220406
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
906 PM PDT Sat Jun 21 2025

.SYNOPSIS...
Gusty westerly winds over the mountains and into the deserts this
evening will weaken somewhat overnight. The marine layer will
remain fairly deep tonight, reaching into the valleys but coverage
could be much less than last night. Below average temperatures
will continue early into next week, with gradual warming for the
middle to end of the week. The marine layer will become shallower
for the middle to the end of the upcoming week.

&&

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

This evening...The afternoon sounding shows the marine layer
marginally than last evening but with a much weaker inversion due
to significant cooling at the top of the inversion. Low cloud
coverage is significantly less than at this time yesterday and
high-resolution models show notably less cloud coverage tonight
than last night. One of the models also shows a period of
northerly winds early Sunday morning which could prevent low
clouds from affecting much of the IE. Periods of gusty westerly
winds will continue over the mountains and into the deserts
through tonight, with some weakening. At this hour, the wind-
prone locations are reporting wind gusts of 35 to 61 mph.

From previous discussion...
For early in the upcoming week, a long wave troughing pattern will
remain over the Western United States. That will keep high
temperatures 5 to 10 degrees below average through Tuesday. Even
remaining below average, temperatures between today and Sunday are
expected to increase 3 to 7 degrees. A brief period of offshore
winds can be expected Sunday morning on the coastal mountain slopes,
with minimal impact expected. Marine layer low clouds and fog are
expected each night and morning and will reach into the valleys.

For Wednesday through the end of the upcoming week, the upper level
troughing shifts north, allowing for weak ridging to build in. That
will bring a gradual warming. Current forecast for the end of the
week follows the NBM solution, with highs within a few degrees of
normal. The increased ridging will result in a shallower marine
layer, with persistent low cloud coverage along the coast and
less coverage expected in the valleys.

&&

.AVIATION...
220300Z....Coast/Valleys... Low clouds based 2500-3000 ft MSL should
spread into San Diego County over the next few hours. Past that
point, confidence in coverage and location of CIGs is low. FEW-SCT
clouds will likely spread into the Inland Empire and Orange County
after 06z, but a disrupted marine layer will struggle to produce BKN
CIGs. Additionally, a coastal eddy should work with weak offshore
flow to pull low clouds back toward the coast beginning around 09-
12z. Thus, any CIGs that develop tonight will quickly scatter to the
coast by 14-16z Sunday. Expect full clearing Sunday afternoon. Low
clouds struggle to form again Sunday evening, but should eventually
fill into San Diego/Orange Counties after 06z Monday.

.Mountains/Deserts...Clear skies and unrestricted VIS through
Sunday evening. Strong westerly winds occurring now, with gusts 30-
50 knots this evening for mountain passes and locally into deserts.
Moderate up/downdrafts in lee of mountains/mountain passes as well
as isolated BLDU in the desert with VIS 3-5SM at times. Winds
diminish 06-09z in the High Desert and 09-12z in the Coachella
Valley. A brief period of strong northerly winds will occur along
the northern slopes of the Coachella Valley around 09-15z.

&&

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

&&

.BEACHES...
Elevated surf 3-5 feet with sets to 6 feet will continue through
Sunday morning for west facing beaches.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 11 PM PDT this evening for Apple and Lucerne
     Valleys-San Diego County Deserts-San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE/BEACHES...KW