Spring Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

121
FXUS66 KSGX 200417
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
917 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...

Evening update...
Numerous daily and monthly high temperature records were broken or
tied again today, including Idyllwild which broke their monthly
high temperature for the third day in a row with a high of 90
degrees. Indio and Thermal tied the national high temperature
record for March with a high of 108 degrees.

Patchy low clouds and fog have developed just off the coast of far
southern San Diego County again this evening but have yet to make
it over land, though satellite imagery is showing it nearing
Point Loma. Occasional dense fog is possible at the beaches from
about Solana Beach southward tonight into early Friday morning.
The large upper level high currently centered over the lower
Colorado River Valley will shift eastward and weaken slightly on
Friday, allowing for very minor (1 to 2 degrees) cooling west of
the mountains with little change in the deserts.

Previous discussion...
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.

&&

.CLIMATE...
Here are a list of locations currently forecast to break/tie
monthly high temperature records on Friday:

Friday:

             FORECAST HIGH  RECORD YEAR     AVG    +/-

    RIVERSIDE         100    98 IN 1997      73    27   Monthly Record: 102
    RAMONA             95    92 IN 1997      68    27   Monthly Record: 95
    ALPINE             93    86 IN 2001      68    25   Monthly Record: 96
    BIG BEAR LAKE      70    70 IN 1997      52    27   Monthly Record: 80
    IDYLLWILD          85    77 IN 1997      60    25   Monthly Record: 90
    PALOMAR MOUNTAIN   85    76 IN 1972      57    28   Monthly Record: 83
    LAKE CUYAMACA      87    79 IN 1956      56    31   Monthly Record: 84
    CAMPO              95    87 IN 1997      69    26   Monthly Record: 96
    PALM SPRINGS      107    97 IN 1997      80    27   Monthly Record: 107
    INDIO             108    98 IN 1997      81    27   Monthly Record: 108
    THERMAL           108   101 IN 1997      82    26   Monthly Record: 108
    BORREGO           106    95 IN 2017      80    26   Monthly Record: 105

Here are a list of locations currently forecast to break/tie
monthly highest low temperature records on Friday:

Friday:


             FORECAST LOW   RECORD  YEAR

    ANAHEIM            63     59 IN 2015 Monthly Record: 69
    VISTA              62     59 IN 2015 Monthly Record: 67
    RIVERSIDE          66     58 IN 2015 Monthly Record: 66
    LAKE ELSINORE      61     57 IN 1986 Monthly Record: 61
    ESCONDIDO          61     59 IN 2015 Monthly Record: 63
    RAMONA             56     50 IN 2023 Monthly Record: 63
    ALPINE             71     55 IN 1990 Monthly Record: 63
    BIG BEAR LAKE      42     38 IN 2017 Monthly Record: 48
    IDYLLWILD          63     43 IN 2017 Monthly Record: 53
    PALOMAR MOUNTAIN   64     56 IN 1997 Monthly Record: 64
    LAKE CUYAMACA      65     53 IN 2017 Monthly Record: 55
    CAMPO              57     51 IN 1951 Monthly Record: 58
    PALM SPRINGS       75     64 IN 2017 Monthly Record: 78
    INDIO              72     69 IN 2010 Monthly Record: 76
    THERMAL            69     64 IN 2013 Monthly Record: 69
    BORREGO            69     64 IN 2013 Monthly Record: 73

&&

.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/CLIMATE...SS
AVIATION/MARINE...Westerink