282
FXUS66 KSGX 022347
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
447 PM PDT Fri Oct 2 2026

.SYNOPSIS...
High pressure will intensify into the weekend and linger into next
week. This will bring a long-duration heat wave for areas west of
the mountains. Increased Santa Ana winds will also occur today
through the weekend as well. The peak of the heat will be this
weekend, but confidence is still low on how long the heat lasts into
the end of next week.

&&

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


...UPDATED AVIATION DISCUSSION...

The thin marine layer gave it one last try this morning, with foggy
conditions within 5 miles of the coastline. High pressure aloft will
subtly strengthen into the weekend, causing the marine layer to thin
even further with mainly clear skies going forward each night.
Clockwise flow around the high pressure system to our northwest has
allowed Santa Ana winds to move into the area. We have already
gusted over 50 mph in some spots this morning across the San Diego
County Mountains. Locally gusty conditions will continue this
afternoon and overnight, before strengthening further late Saturday
morning and afternoon. Model guidance shows a fairly good chance (60-
65%) chance of far inland valley locations like Ramona gust to 35
MPH. Since this wind will be mainly easterly, the strongest winds
will once again be across the San Diego Co mts and inland valleys,
as well as the Inland Empire. Winds become weaker by Sunday in these
areas with gusts closer to 20-25 MPH. Gusty winds and lower relative
humidity each day will lead to elevated to near-critical fire
weather conditions, so make sure to do your part that leads to one
less spark!

The main story will be the heat wave that is expected for areas west
of the mountains. Much warmer weather is already occurring today
with highs 10-15 degrees warmer than yesterday. The area of high
pressure over the Desert Southwest will not move very much, with
slight fluctuations in intensity. This, combined with increased
Santa Ana winds on Saturday, will most make this day to be the
hottest day of the event. Those within about 10 miles or more of the
coast have a 60-90% chance of seeing triple digit heat on Saturday,
similar chances on Sunday. Always a tricky forecast with an offshore
winds pattern, where locations that do see an elevated east or
northeast winds will be hotter than those who do not. The same will
go for overnight temperatures as light offshore winds and a warm air
mass will keep lower temperatures well into the 70s for areas west
of the mountains. Other locations across the mountains and deserts
will still see highs 5 to 10 degrees above normal.

The area of high pressure may weaken slightly by the first half of
next week, but changes in temperatures will be rather minimal.
Multiple days of the heat will lead to high heat risk west of the
mountains, so make sure to be in areas of A/C and check on those
without effective cooling. Models hint at the high becoming weaker
by the end of next week, but just how weak it becomes is still
uncertain. The forecast still has an outlook of temperatures above
normal, but please keep up with the latest forecast for additional
details.

&&

.AVIATION...
022345Z...Coast/western valleys: Mostly clear skies expected through
the period. East winds with gusts up to 25 kts near Camp Pendleton
and southern Orange County after 14z Sat, then weak onshore W/NW
sea breeze prevails after 21z.

Inland Valleys/Foothills/Mountains: East winds over west-facing
foothills, inland valleys and in parts of the Inland Empire, gusting
to 30 kts, to diminish this evening, staying locally elevated
overnight over the western slopes in the mountains. Stronger east
winds expand back throughout inland areas after 15Z Saturday into
the afternoon. MOD UDDFS with wind gusts 30-45 kts.

Otherwise...Clear skies through the TAF period.

&&

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

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning until 8 PM PDT Thursday for Orange County
     Coastal Areas-Orange County Inland Areas-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Coastal Areas-San Diego County Valleys-Santa Ana Mountains
     and Foothills.

     Wind Advisory from 6 AM to 6 PM PDT Saturday for Orange County
     Inland Areas-Riverside County Mountains-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Mountains-San Diego County Valleys-San Gorgonio Pass near
     Banning-Santa Ana Mountains and Foothills.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...Westerink