Tustin, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

474
FXUS66 KSGX 041028
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
328 AM PDT Mon May 4 2026

.SYNOPSIS...
A low pressure system off the central California coast will move
slowly inland through central and southern California through
Tuesday spreading cooling inland with high temperatures on
Tuesday 10 to 15 degrees below average for inland areas and 15 to
20 degrees below average for the mountains. Southwest to west
winds for the mountains and deserts will gust to 35 to 45 mph with
isolated gusts to 60 mph. There is a also chance of showers
through Tuesday. The greater chances for showers are for late this
evening through Tuesday morning and across San Diego County from
the coast to the mountains. It will be dry with a substantial
warming trend for Wednesday through Monday of next week. High
temperatures on Sunday will be 10 to 15 degrees above average for
inland areas to as much as 15 to 20 degrees above average for the
inland valleys and lower coastal slopes of the mountains. There
could be extreme heat in the lower deserts as early as Saturday
and continuing through at least Monday of next week.

&&

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

.SHORT TERM (Today through Wednesday)...
A low pressure system off the central California coast will move
slowly inland through central and southern California through
Tuesday spreading cooling inland with high temperatures on
Tuesday 10 to 15 degrees below average for inland areas and 15 to
20 degrees below average for the mountains. Southwest to west
winds for the mountains and deserts will gust to 35 to 45 mph with
isolated gusts to 60 mph.

There is a slight chance of showers through today from the coast
to the mountains. The greater chances for showers are for late
this evening through Tuesday morning and across San Diego County
from the coast to the mountains. Through Tuesday, rainfall across
Orange, southwestern San Bernardino, and western Riverside
Counties, rainfall could range from less than one-tenth inch near
the coast to one-tenth to locally one-quarter inch in the
mountains. For San Diego County, rainfall could range from one-
tenth inch near the coast to one-tenth to locally one-third inch
in the mountains.

Wednesday will be dry with a substantial warming trend through
early next week. High temperatures on Wednesday will warm as much
as 12 to 18 degree for the mountains and high desert, but with
high temperatures still a few degrees below average for most
areas. High temperatures on Wednesday will range from the mid to
upper 60s near the coast to the 70s for the Inland Empire with the
lower deserts in the upper 80s to around 90.

&&

.LONG TERM (Thursday through Sunday)...
Substantial warming will continue on Thursday with the warming
slowing for Friday through Monday. With the warming, high
temperatures for Monday of next week will be as much as 15 to 20
degrees above average for some inland areas. High temperatures for
next Monday will range from the 70s near the coast to the 90s to
around 100 for the Inland Empire with 105 to 110 for the lower
deserts. The Heat Risk based on the NBM forecast would be
sufficient for an Extreme Heat Warning for the lower deserts
beginning on Saturday and continuing through at least Monday of
next week. The Heat Risk for the inland valleys could be
sufficient for a Heat Advisory beginning on Monday.

&&

.AVIATION...
040930Z....Coast/Valleys...Clouds based mostly between 3500-5500
feet MSL will continue today, with occasional cigs to 2500 feet in
DZ or -SHRA, most likely in San Diego County. Some higher terrain
obscured. Scatter out, not uniform or complete after 18Z, better at
the coast and less likely inland especially against foothills. After
00Z, clouds fill the basin again with bases around 2500-3500 feet
MSL. -SHRA and local bases down to 1800 feet MSL after 04Z into
Tuesday.

Mountains/Deserts...Strong winds will continue to weaken this
morning, only to increase again after 21Z. Westerly gusts 25-35
kts with isolated 45 kts, producing moderate to strong
up/downdrafts and local LLWS in lee of mountains. Patchy reduced
vis in BLDU in deserts. Coast-facing mountain slopes locally
obscured between 4000- 6000 feet MSL in BR with clouds
intersecting terrain through 18Z, then increasing again after 02Z
into Tuesday.

&&

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

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 8 AM this morning to 9 PM PDT this evening
     for Apple and Lucerne Valleys-San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

PUBLIC...17
AVIATION/MARINE...MM