Valle Vista, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

949
FXUS66 KSGX 021557
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
857 AM PDT Fri May 2 2025

.SYNOPSIS...
A low pressure system will move into Southern California this
weekend. It will keep our marine layer deep and the clouds
pervasive and bring cooler weather, especially Sunday. It will
also bring strong winds Saturday afternoon through Sunday along
with scattered showers including snow in the higher mountains.
A smaller chance of showers continues through Tuesday. Dry and
warmer weather expected Wednesday and Thursday.

&&

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

The coastal basin is filled almost to the brim with clouds this
morning. Clouds extend to 3,500-4,000 feet up the coastal slopes,
where true fog is found. The inversion is stronger today and the
cloud is thicker, so clearing will be late and partial or not at
all near the coast. A trough off the NorCal coast will amplify and
drop southward, eventually cutting off from the jet stream and
dropping into SoCal by Saturday evening. Initially, this will
enhance our marine layer even further for Saturday, featuring a
pretty robust eddy. Strong onshore winds come next Saturday
afternoon. Gusts of 35-50 mph will be common across the mountains
and deserts, with isolated gusts through mountain passes into
deserts reaching or topping 65 mph. Finally, the showers arrive
Saturday evening, but not for everyone, and continue through at
least Sunday. The trough axis moves east of our area, but rotating
lobes of vorticity and moisture contine to drop south through
SoCal through Tuesday. That will keep small chances of showers in
the forecast, but with a more emphasis inland. There is a slight
chance of thunderstorms Sunday afternoon in the high desert and
mountains. Precipitation amounts are not impressive: near zero
near the coast, ramping up to about one-third inch in the
mountains, but locally higher where any thunderstorm occurs. Model
trends have stepped back on the cold air and instability of this
system. Snow levels are now bottoming out at around 6,000 feet and
widespread thunderstorm chances have been trimmed back. Snowfall
still looks like 1 to 3 inches, but only accumulating above 6,500
feet. Winds drop off some Sunday afternoon and evening. High
temperatures on Sunday will flirt with low max temp records with
upper 50s to lower 60s in the coastal basin, 40s and 50s in the
mountains, 60s in the high desert and 70s in the low desert. Yeah,
that`s cold for May, 15-20 degrees below normal for some inland
areas. Isolated to scattered showers will continue on Monday and
Tuesday, but the best chances will be in the mountains. Finally,
the pulses of energy from the north will stop and the trough
continues to weaken and move east. That will bring dry and warmer
weather Wednesday and especially Thursday. The longwave ridge
amplifies quite well over our region Wednesday and beyond, but
there is some weak shortwave troughing that dampens it. The
warming trend should be enough to bring temperatures above normal
Thursday and Friday. 70s at the coast and 80s inland might feel
good for a change. Meanwhile, the marine layer should rebuild
quickly to reestablish our seasonal nocturnal cloud pattern near
the coast.

&&

.AVIATION...
021545Z....Coasts/Valleys...A deep marine layer has filled the
coastal basin with bases 2000-2500 feet and tops around 3500 feet.
Clearing will be slow to occur with inland areas scattering from 16-
18z and later for coastal areas. There is a 25% chance that parts of
the San Diego County coast remain BKN through the afternoon.
Regardless, low clouds will surge inland over San Diego County as
early as 0z this evening and eventually spread to the rest of the
coastal basin. Bases and tops should remain around 2000-2500 feet
and 3000-3500 feet, respectively. Areas of DZ possible along the
coast Saturday morning. Slow clearing once again for inland areas on
Saturday and coastal areas will likely remain broken through the day
as a low pressure system approaches.

Mountains/Deserts...ISO TSRA possible from Idyllwild to Big Bear 20Z
Fri-03Z Sat. Otherwise, SKC through tonight until SCT/BKN high
clouds move over Southern California on Saturday. Increasing winds
for the deserts and desert slopes Saturday with widespread 20-30kts
and 40kts through mountain passes by 0z Sunday.

&&

.MARINE...
Gusty west to northwest winds will develop over the coastal waters
Saturday, strongest late Saturday afternoon into early Sunday
morning. Sustained winds 15-20 kts for inner coastal waters and 20-
30 kts for outer coastal waters. There is an 40% chance of wind
gusts exceeding 34 kt near San Clemente Island in the outer coastal
waters and a less than 5% chance over the inner coastal waters early
Sunday morning. A Gale Watch remains in effect from Saturday
afternoon through Sunday morning. Combined seas of 8-11 feet in the
outer coastal waters and 6-8 feet in inner coastal waters with
steep, wind-driven waves are expected. Wave heights peak Sunday
morning and gradually lower Sunday afternoon into Monday.

&&

.BEACHES...
8-11 foot swell with a 6-9 second period  from the west will bring
elevated surf conditions on Sunday.  Elevated surf of 3-6 ft is most
likely with sets to 7 ft in southern San Diego County. Elevated surf
may continue into Monday morning. Surf and a high risk of rip
currents will create hazardous swimming conditions at all beaches
Sunday. Swell and surf will lower later on Monday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Gale Watch from Saturday afternoon through Sunday morning for
     Waters from San Mateo Point to the Mexican Border Extending
     10 to 60 nm out including San Clemente Island.

&&

$$

PUBLIC...MM
AVIATION/MARINE/BEACHES...KW