Fawnskin, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

733
FXUS66 KSGX 171019
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
319 AM PDT Thu Jul 17 2025

.SYNOPSIS...
Monsoonal moisture will increase today, decrease slightly on
Friday, with a greater decrease over the weekend. This will bring
a chance of showers and thunderstorms through Friday, mostlikely
over the mountains and during the afternoons. Drying is expected
during the weekend through the middle of next week. High
temperatures for the deserts will be a few degrees cooler for
today and Friday, a few degrees warmer for the weekend, with most
areas a few degrees cooler for early next week.

&&

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

.SHORT TERM (Today through Saturday)...
The precipitable water value on the NKX sounding late Wednesday
afternoon was 1.29 inch. ECMWF ensemble output shows precipitable
water values peaking late this afternoon, decreasing slowly on
Friday, with a greater decrease for Saturday and Sunday.

While the marine layer depth is not much different from 24 hours
ago, marine layer cloud cover is much reduced over land areas of
southwestern California and the coastal waters of San Diego
County. Some patchy coverage of low clouds may return near the
coast around sunrise, but not extend inland much past the coast.

Satellite imagery shows more extensive mid and high cloudiness
across southwestern Arizona moving slowly westward into the lower
deserts of southern California. This cloud cover is associated
with a Mesoscale Convective Vortex that has been moving slowly
westward across southern Arizona. There have been showers and
isolated thunderstorms overnight with this MCV with the more
widespread showers on the northern side of the MCV.

For today, increasing mid and high cloud cover may limit daytime
heating with afternoon convection more elevated and less tied to
terrain with lesser chances for thunderstorms and isolated heavier
rainfall.

For Friday, there may be greater clearing of the mid and high
clouds, but with sufficient remaining moisture for thunderstorm
development over the San Bernardino Mountains and Riverside County
mountains during the afternoon with isolated brief heavier
rainfall.

High temperatures for today and Friday will be a few degrees
cooler for the deserts with today the likely cooler day. Drying
with warming for the deserts will begin on Saturday with only a 10
to 15 percent chance for afternoon showers or thunderstorms for
the mountains on Saturday afternoon as the monsoonal moisture
decreases.

&&

.LONG TERM (Sunday through Wednesday)...
Drying will continue for Sunday into the middle of next week.
The deserts will warm a few more degrees on Sunday with most areas
a few degrees cooler for early next week. Night and morning
coastal low clouds will spread into portions of the western
valleys late each night.

&&

.AVIATION...
170930Z....Coast/Valleys...Patchy low clouds along the immediate
coast based 1200-1800 ft MSL are expected to become slightly more
widespread towards 11Z, but confidence in impacts at coastal sites
is low. There is a 65% chance for BKN-OVC cigs at KSAN and KCRQ by
13Z this morning, with lower chances at KSNA. Any clouds will
scatter 16-17Z this morning. Still patchy clouds, but likely more
widespread than tonight, with similar bases will push ashore after
18/04Z. Otherwise, 15-20% chance for thunderstorms and rain showers
to move westwards off the mountains into the eastern valleys, best
chances 18-01Z today and increasing clouds 10000-15000 feet.

Mountains/Deserts...Increasing clouds 10000-15000 feet today. ISO-
SCT SHRA/TSRA over the mtns after 18Z today, with slight chance TSRA
for the deserts. Highest chances through late this afternoon, but an
isolated storm is possible overnight. Associated wind gusts, UDDFS,
and VIS restrictions possible with any storm that develops.

&&

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

&&

.BEACHES...
A moderate period south-southwesterly swell (2-3 feet at 15-16
seconds) will continue to generate elevated surf and a high risk of
rip currents through today. Surf of 3-5 feet expected with sets to 6
feet possible, primarily on southerly facing beaches. Swell and surf
will begin to lower on Friday.

&&

.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...17
AVIATION/MARINE/BEACHES...CSP