Alpine, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

333
FXUS66 KSGX 130418
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
918 PM PDT Thu Jun 12 2025

.SYNOPSIS...
Subtle warming will occur across inland areas through the weekend
as an area of high pressure strengthens over the desert southwest.
The marine layer will remain quite consistent, with night and
morning low clouds near the coast into the western valleys. Weak
troughing and ridging across the Southwest next week will lead to
minor fluctuations in high temperatures and the marine layer.

&&

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

This evening...The marine layer is a little deeper than yesterday
evening, at about 2000 ft. There was some cooling above the
inversion, making it a little weaker than yesterday. Low clouds
have already spread about 10-15 miles inland and will likely
spread farther inland than last night as sfc pressure gradients
trend a little stronger onshore. This afternoon, high
temperatures approached 110 degrees at some locations in the lower
deserts, and reached the low 90s in some valley locations...mainly
in the IE.

From previous discussion...
An area of high pressure over Baja California will strengthen and
push northward across the Southwest by the weekend. 850 mb
temperatures will increase to around 30C by Sunday. As a result
of this, warmer temperatures can be expected away from the coast
with highs 5 to 10 degrees above normal. High temperature
probabilities have gone slightly downward over the past couple of
days, but we will still be seeing hot weather across inland
valleys and desert areas, with moderate to locally high heat
risk. There is high confidence in seeing temperatures above 110
degrees in the lower deserts and moderate confidence in seeing
highs reach 100 degrees for places in the Inland Empire and
populous areas of the high desert.

A weak trough will cross California early next week, which will
aid in lowering temperatures closer to normal. Night and morning
low clouds will still continue at the coast and western valleys.
Another area of high pressure may gain strength by the middle of
next week, which would lead to another subtle warm up.

&&

.AVIATION...
120330Z....Coast/Valleys...Low clouds based around 0900-1600 feet
MSL will continue to move inland throughout the evening, and
eventually into the valleys early tomorrow morning, but not as
extensively as the previous morning. Bases will continue to fall to
around 500-1000 ft MSL with vis reduced 0-5SM over higher coastal
terrain between these levels. Clouds clearing 15-17Z Fri for inland
areas and 18-20Z for coastal regions. Clouds will again linger along
the beaches, but with better chances for brief clearing at KCRQ
(70%) and moderate chances at KSAN (40%). Clouds will begin to
regather and fill back in from west to east tomorrow evening with
very similar timing and cloud bases as they were this evening,
mainly after 00Z Sat.

Mountains/deserts...Mostly clear skies and unrestricted vis expected
through tomorrow night.

&&

.MARINE...
No hazardous marine conditions are expected today through Tuesday.

&&

.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...Stewey