Helendale, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

066
FXUS66 KSGX 090408
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
908 PM PDT Tue Jul 8 2025

.SYNOPSIS...
Warming conditions through the middle of the week, with the hottest
days expected to be Wednesday and Thursday for inland locations.
Temperatures will return to near average west of the mountains
for the weekend into early next week, with above average
temperatures remaining in the deserts. The marine layer will
become shallower for the middle of the week, mainly impacting
coastal areas, before deepening again over the weekend.

&&

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

This evening...The marine layer is much shallower than yesterday
and at this hour, only patches of low clouds and fog are forming
along the coast of southern San Diego County. Variable mid and
high clouds will likely continue overnight and could help to bring
only patchy low clouds and fog in the coastal areas overnight.

From previous discussion...
An upper level low centered off the coast of northern California
will weaken and move inland tonight into Wednesday morning while
high pressure aloft centered over Arizona and New Mexico expands
across southern California. This will bring additional warming for
Wednesday, with little change for Thursday. The marine layer will
become shallower and patchy Wednesday and Thursday, keeping low
clouds and fog that develop more confined to coastal areas.

With the upper level high expanding west across Southern California
Wednesday and Thursday, above average temperatures are expected for
inland locations. Highs on Wednesday and Thursday are expected to be
5 to 10 degrees above average for inland locations. High
temperatures Wednesday and Thursday will range from the 70s near the
coast; the upper 90s to 104 for the Inland Empire; and 114 to 118
for the lower deserts. In the mountains below 5000 ft, highs are
expected to be in the mid-80 to upper 90s. Widespread moderate
HeatRisk is expected for the valleys and mountains, with widespread
major HeatRisk in the low deserts. Make sure you`re staying
hydrated, seeking shade, and avoiding strenuous activity during the
hottest parts of the day if possible.

High pressure aloft will remain over Southern California Friday into
early next week, but will weaken slightly. The weakening of the high
aloft will result in highs on Friday 3 to 5 degrees cooler than
Thursday across the area, with not much change into the weekend. NBM
high temperatures for the coast and valleys are forecast to be up to
5 degrees below average with the deserts around 5 degrees above
average. The marine layer will deepen Sunday through Tuesday with
night and morning coastal low clouds extending inland to the western
valleys.

&&

.AVIATION...
090315Z....Coast...SCT high clouds above 15000 feet MSL. Patchy low
clouds with intermittent coverage to develop after 06Z with bases
700-1000 feet MSL, most likely vcnty KSAN (55% chance). Scatter out
of any cigs by 16Z. Slightly more extensive low clouds with similar
bases to develop after 06Z Thu.

Valleys/Mountains/Deserts...VFR conditions with SCT-BKN high clouds
above 15000 feet MSL, thinning Wednesday.

&&

.MARINE...
Northwest wind gusts around 20 kts near San Clemente Island this
evening as well as Wednesday afternoon and evening. Otherwise, no
hazardous marine weather is expected through Sunday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 10 AM Wednesday to 8 PM PDT Thursday for
     Riverside County Mountains-San Bernardino and Riverside
     County Valleys-The Inland Empire-San Diego County Mountains-
     San Diego County Valleys.

     Extreme Heat Warning from 10 AM Wednesday to 8 PM PDT Thursday
     for Coachella Valley-San Diego County Deserts-San Gorgonio
     Pass near Banning.

PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE...CSP