Spring Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

118
FXUS66 KSGX 200047
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
547 PM PDT Thu Mar 19 2026

.SYNOPSIS...
Widespread moderate with areas of major HeatRisk will continue
through Friday. HeatRisk will decrease for the weekend, with minor
cooling. Even with the cooling, temperatures will remain above
average into next week. Patchy marine layer low clouds and fog will
be present at times, most likely to impact the coastal waters and
immediate coast.

&&

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

Multiple daily and monthly high and low temperature records were
broken yesterday with more expected to be broken today and Friday.
The latest record report is headlined on our weather.gov/sandiego
homepage. A climate section can be found below listing locations
that are currently forecast to tie or break their monthly records.
Widespread moderate to locally major HeatRisk is expected through
Friday for most locations and Saturday in the low desert. Reduce
outdoor activities if possible between 10 AM and 5 PM, seek shade,
and stay hydrated.

The high pressure aloft will peak in strength over the
California/Arizona border today with temperatures 20 to 30 degrees
above average for this time of year. Overnight lows will also be
elevated, which will limit overnight relief from the heat for most
inland locations. Through Friday widespread temperatures in the 90s
to low 100s expected for the inland valleys, with highs in the mid-
80s to low 90s for coastal areas away from the immediate coast and
the lower elevations of the mountains. In the low deserts, highs
will likely exceed 105 degrees in most locations through Saturday.
Chances for exceeding 110 degrees on Friday are 60 percent for
Indio, 20 percent for Palm Springs, and 10 percent for Borrego
Springs. In the High Desert, temperatures will be in the mid-90s.

Weakening high pressure aloft and strengthening onshore flow will
bring 4 to 8 degrees of cooling Saturday. That will be most
noticeable for locations west of the mountains, but even the deserts
will cool 3 to 5 degrees. A weak low pressure system aloft will move
east through Southern California into the Great Basin sometime
Sunday or Monday. that will bring an uptick in westerly winds
Saturday, which have the potential to turn weakly offshore by Sunday
afternoon into Monday morning. Ridging aloft looks to rebuild Monday
and strengthen into the middle of the week. This ridge isn`t expected
to be as strong as the one over Southern California this week, but
it will be enough to maintain above average temperatures through
next Thursday. Widespread minor with areas of moderate HeatRisk will
be present in the valleys and low desert for much of next week.

With the ridge axis shifted further east today, weak onshore flow
has returned to coastal areas. The weak onshore flow was enough to
allow patchy dense fog along the immediate coast this morning. Areas
of patchy dense fog over the water and at the coast is possible each
morning through Saturday. With the aforementioned passing weak low
pressure onshore flow will briefly increase, making chances of dense
fog less likely for Sunday morning. Low cloud and fog coverage on
Sunday morning may reach into the western valleys. Weak offshore
flow early next week may keep low clouds and fog patchy and more
confined to the immediate coast again.


&&

.AVIATION...
200030Z...Patchy low clouds based less than 500 ft MSL are expected
to surge over the waters of southern SD County 02-04z this evening
and slowly develop off of the rest of the coastline in patchy
fashion after 04z. Likely timing VCFG for KSAN around 03z and KCRQ
around 05z, bringing slight chance for intermittent impacts. FG
starts moving into coastal areas 06-08z, bringing higher chance for
patchy cigs below 500 ft MSL and vis < 1 SM. 60% for VIS below 1SM
at times at KSAN and 40% for KCRQ. Greater uncertainty for KSNA with
a slight (30%) chance for VIS/cig reductions mainly after 13z Fri.
Clearing 15Z-17Z. Everywhere else, VFR conditions expected through
the TAF period.

&&

.MARINE...Patchy fog is expected to surge from the south this
evening, lowering visibility to less than 1 NM locally. Visibility
improvements expected mid-morning Friday. Otherwise, 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...Heat Advisory until 8 PM PDT Friday for Orange County Coastal
     Areas-Orange County Inland Areas-Riverside County Mountains-
     San Bernardino County Mountains-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Coastal Areas-San Diego County Mountains-San Diego County
     Valleys-Santa Ana Mountains and Foothills.

     Extreme Heat Warning until 8 PM PDT Saturday for Coachella
     Valley-San Diego County Deserts-San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE...Westerink