National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KSGX 171002
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
302 AM PDT Wed Apr 17 2024

.SYNOPSIS...
A weak low pressure system will move inland across southern
California Thursday night and Friday. The deserts will be warmer
today with cooling spread inland for Thursday and Friday with
stronger and gusty southwest to west winds for the mountains and
deserts for each afternoon and night through Friday night. Low
clouds and fog near the coast this morning will spread inland into
portions of the valleys for late tonight into Thursday morning and
across much of the valleys by Friday morning. Warmer for the
weekend with high pressure aloft, then a cooling trend for Monday
and Tuesday.

&&

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

.SHORT TERM (Today through Friday)...
Low clouds have developed along portions of the San Diego County
coast early this morning and are expected to increase in coverage
and spread northward along the coast into this morning as a weak
coastal eddy develops. High temperatures for the deserts are
expected to warm another 5 degrees today with high temperatures
for much of the coast and valleys within a few degrees of those
on Tuesday.

As a weak low pressure system moves inland through southern
California on Thursday night and Friday, cooling will spread
inland and the marine layer will deepen. Coastal low clouds will
spread into portions of the valleys for late tonight into Thursday
morning, then across most of the valleys for late Thursday night
into Friday morning.

There will be stronger onshore flow with stronger and gusty
southwest to west winds for the mountains and deserts each
afternoon and night through Friday night with the stronger gusts
to 40 to 50 mph.

&&

.LONG TERM (Saturday through Tuesday)...
High pressure aloft over southern California for the weekend will
bring warming for Saturday and Sunday with the marine layer
becoming shallower. Coastal low clouds will extend inland into
portions of the valleys for Friday night, then be patchier and
confined mostly to coastal areas for Saturday night into Sunday
morning.

High temperatures on Saturday will be a few to around 5 degrees
warmer than Friday with the greatest warming for the mountains and
inland valleys. Sunday high temperatures will be a few to around 5
degrees warmer than Saturday with the greatest warming in the
valleys. With the warming, high temperatures for Sunday will be as
much as 10 to 15 degrees above average for the mountains and high
desert. NBM has a 79 percent chance for Palm Springs to have a
high temperature of 100 or higher on Sunday.

For Monday and Tuesday, a low pressure system over the eastern
Pacific will move eastward toward California with model
differences in timing and intensity. While cooling is expected
for Monday and Tuesday, how much on each day is less certain. For
Tuesday, NBM has high temperatures still around 5 degrees above
average for the deserts while the coast and valleys are a few to
around 5 degrees below average. Deepening of the marine layer is
expected with coastal low clouds spreading farther inland into the
valleys by Tuesday morning.

&&

.AVIATION...
170930Z...Coast...Patchy low cloud coverage will occur through 16Z
today. Bases would be 700-900 feet MSL with vis 3-6SM or 1-3SM on
higher coastal terrain. Low clouds will redevelop after 03Z tonight
with more expansive and uniform coverage overnight into Thursday.
Bases should be 800-1200 feet MSL with tops to 1600 feet.

Otherwise...mostly clear skies with unrestricted vis today, with
some increase in high clouds tonight.

&&

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

&&

.BEACHES...
A long-period swell (3 feet/17 seconds/200 deg) from the southern
hemisphere will build surf up to 6 feet today through Thursday,
especially on south-facing beaches. This will generate a high rip
current risk.

&&

.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...MM