La Habra Heights, California Weather Forecast Discussion

516
FXUS66 KSGX 051535
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
835 AM PDT Fri Sep 5 2025
.SYNOPSIS...
Generally seasonal temperatures will prevail through the weekend
with decreasing chances for afternoon thunderstorms for the
mountains and deserts on Saturday with dry weather for Sunday.
A low pressure system will move slowly inland into the western
states next week bringing drying and a gradual cooling trend.
With the cooling, high temperatures on Wednesday and Thursday will
be a few degrees below average near the coast to as much as 10 to
15 degrees below average for the mountains, high desert, and
inland valleys.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.Morning Update...
GOES imagery this morning shows low clouds around ten miles inland
from the coast, where some valleys are beginning to clear. Outflow
from a complex of thunderstorms in Arizona has also contributed to
some clouds out in the lower deserts as well. No major forecast
changes for this afternoon as thunderstorms will begin to arise
across the mountains. Thunderstorms will reform again once more on
Saturday. High temperatures will be similar through the
weekend before quieter and cooler weather moves into the region
by next week.
.Previous Discussion (356 AM Friday)...
.SHORT TERM (Today through Sunday)...
Late Thursday evening, outflow from thunderstorms spread westward
into the deserts and mountains in San Diego County and
northwestward across the Coachella with the strongest gust to 46
mph at Thermal at 10:32 PM. This outflow pushed dewpoints in the
lower deserts mostly into the lower 70s.
Coverage and intensity of thunderstorms for this afternoon for the
mountains and deserts is expected to be similar to Thursday
afternoon with the greatest coverage and rainfall amounts over the
mountains of San Diego and Riverside Counties with the highest HREF
90th percentile hourly rainfall of around 0.9 inch for this
afternoon and around 0.5 inch for Saturday afternoon with lesser
coverage and amounts. Dry weather is expected for Sunday.
Coverage of night and morning coastal low clouds will gradually
increase through the weekend with low clouds over the coastal
waters spread locally inland into coastal areas late each night.
High temperatures for today may be a few degrees cooler than
Thursday followed by a degree or so of warming on Saturday and
another degree or so of warming on Sunday. High temperatures on
Sunday are expected to be near average at the coast to a few
degrees below average for inland areas, ranging from the 70s near
the coast to the 90s for the Inland Empire with 100 to 104 for
the lower deserts.
&&
.LONG TERM (Monday through Thursday)...
A low pressure system will move slowly inland into the western
states next week bringing drying a gradual cooling trend. With the
cooling, high temperatures on Wednesday and Thursday will be a few
degrees below average near the coast to as much as 10 to 15
degrees below average for the mountains, high desert, and inland
valleys. High temperatures on Wednesday and Thursday will range
from the lower to mid 70s near the coast to the upper 70s to mid
80s for the Inland Empire with the lower to mid 90s for the lower
deserts. Night and morning coastal low clouds and fog will spread
into the far western valleys late each night at times.
&&
.AVIATION...
051530Z...Coast...Low clouds based 500-1200 ft MSL have filled into
most coastal areas and some western valleys this morning, with only
slight erosion occurring from east to west at this hour. There are
also several locations with reduced vis down to 2SM in BR. This is
expected to clear with improving visibilities to the beaches by 15-
17Z, and clear over waters shortly, thereafter. Clouds return to
waters and coastal land areas later this evening after 06z Saturday
with similar bases, but less inland extent.
Valleys/Mountains/Deserts...Isolated SHRA/TSRA expected over San
Diego County and southern Riverside County mountains again this
afternoon from 19-01Z, with slighter chances (15-20%) for more
northerly mtns and deserts/desert foothills. CB bases of about 10000
feet MSL with TSRA tops to 35k feet. Gusty, erratic winds, blowing
dust with low visibility, lightning, and lower bases 6000-9000 feet
MSL will occur with any TSRA.
&&
.MARINE...
No hazardous marine conditions are expected through Monday.
&&
.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...APR
AVIATION/MARINE...Stewey

NWS SGX Office Area Forecast Discussion