963
FXUS66 KSGX 171818
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1118 AM PDT Tue Mar 17 2026

.SYNOPSIS...
Hot conditions with record breaking temperatures this week. Weak
offshore flow is expected today, with east to northeast wind gusts
25 to 45 mph along and below the coastal slopes of the mountains.
Some cooling is expected through the weekend into early next week.
Even with the cooling high temperatures will remain above average.
Marine layer low clouds and fog will be largely absent from the
coast this week, potentially returning by late this weekend.

&&

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

Weak offshore flow is being observed across the area as of 11 AM.
The strongest northeast to east winds are being observed on the
coastal mountain slopes and below passes with peak gusts 30 to 45
mph. These offshore winds combined with building high pressure aloft
will make for a toasty day, especially for the coast and western
valleys. Temperatures in both coastal and inland Orange County are
running 15 to 25 degrees warmer than this time yesterday. Further
south in San Diego County, temperatures are running 7 to 15 degrees
warmer than yesterday. A few daily high and low temperature records
were broken yesterday with more expected to be broken today.
Widespread moderate to locally major HeatRisk is expected each day
this week. Reduce outdoor activities if possible between 10 AM and 5
PM, seek shade, and stay hydrated.

Places along the immediate coast will see some relief from the heat
Wednesday onward, as weak onshore flow returns. That won`t be the
case for inland locations, with an addition 3 to 5 degrees of
warming on Wednesday and even further warming for Thursday and
Friday. The high pressure aloft will peak in strength on Thursday or
Friday with high temperatures 20 to 30 degrees above average for
this time of year. Daily and monthly temperature records are
expected to be broken or tied for locations like Ramona, Big Bear
Lake, Idyllwild, Palm Springs, and Borrego Springs. More information
on monthly temperature records can be found in the climate section
below. Overnight lows will also be elevated, which will limit
overnight relief from the heat for most locations.

Weakening high pressure aloft and strengthening onshore flow will
bring 5 to 7 degrees of cooling to place west of the mountains
Saturday, with cooling spreading to the mountains and deserts Sunday
and Monday. Weak ridging aloft will maintain highs 10 to 20 degrees
above average across the area through at least next Tuesday. Much of
this week will see an absence of marine layer low clouds and fog,
with the potential for clouds and fog to return to coastal areas
late in the weekend or early next week.

&&

.AVIATION...
171800Z...VFR conditions expected through the TAF period. Gusty
winds around 25-30 kts out of the northeast are beginning to
decrease and will continue to do so through 21Z. Isolated low clouds
along the coast beginning near KSAN after 05Z and stretching north
near KCRQ after 06Z. Not expecting any impacts to cigs or vis at
coastal airports.

&&

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

&&

.BEACHES...
A long period (17-19 second) south-southwesterly swell (190-200
degrees) to 3-5 feet will continue today, bringing occasional surf
sets up to 6 feet on south-facing beaches, before decreasing
Wednesday evening. Locally hazardous swimming conditions are
expected. A Beach Hazards Statement contains more details.

&&

.CLIMATE...

Here are a list of locations currently forecast to break/tie
monthly high temperature records Wednesday through Friday:

Wednesday:

                      HIGH  RECORD YEAR     AVG    +/-

    RAMONA             94    89 IN 1997      68    26  Monthly Record: 94
    IDYLLWILD          85    75 IN 2004      60    25  Monthly Record: 82
    PALOMAR MOUNTAIN   83    74 IN 2004      57    25  Monthly Record: 82
    LAKE CUYAMACA      85    76 IN 2007      56    30  Monthly Record: 82
    CAMPO              94    89 IN 2004      68    26  Monthly Record: 92
    PALM SPRINGS      106    95 IN 1990      79    28  Monthly Record: 104
    INDIO             105    99 IN 2007      81    26  Monthly Record: 104
    THERMAL           106    97 IN 1997      82    27  Monthly Record: 103
    BORREGO           103    97 IN 1972      80    24  Monthly Record: 101


Thursday:

             FORECAST HIGH  RECORD YEAR     AVG    +/-
    RAMONA             97    92 IN 1997      68    28   Monthly Record: 94
    BIG BEAR LAKE      80    70 IN 1997      52    28   Monthly Record: 80
    IDYLLWILD          87    77 IN 1997      60    27   Monthly Record: 82
    PALOMAR MOUNTAIN   85    76 IN 2007      57    28   Monthly Record: 82
    LAKE CUYAMACA      87    79 IN 1956      56    30   Monthly Record: 82
    CAMPO              95    87 IN 1997      69    26   Monthly Record: 92
    PALM SPRINGS      107    97 IN 1997      80    29   Monthly Record: 104
    INDIO             106    98 IN 1997      81    28   Monthly Record: 104
    THERMAL           108   101 IN 1997      82    29   Monthly Record: 103
    BORREGO           105    95 IN 2017      80    24   Monthly Record: 101

Friday:

             FORECAST HIGH  RECORD YEAR     AVG    +/-

    RAMONA             95    92 IN 1997      68    28   Monthly Record: 94
    BIG BEAR LAKE      81    72 IN 2004      52    29   Monthly Record: 80
    IDYLLWILD          87    79 IN 2004      60    27   Monthly Record: 82
    PALOMAR MOUNTAIN   85    76 IN 1972      57    29   Monthly Record: 82
    LAKE CUYAMACA      87    75 IN 2004      56    32   Monthly Record: 82
    CAMPO              96    92 IN 1997      69    27   Monthly Record: 92
    PALM SPRINGS      108    98 IN 2004      80    31   Monthly Record: 104
    INDIO             108   100 IN 2004      81    31   Monthly Record: 104
    THERMAL           108   101 IN 2004      82    32   Monthly Record: 103
    BORREGO           106    97 IN 1997      80    26   Monthly Record: 101

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

Wednesday:

              FORECAST LOW   RECORD  YEAR

    RIVERSIDE          67     57 IN 1995  Monthly Record: 66
    LAKE ELSINORE      63     55 IN 2015  Monthly Record: 61
    ESCONDIDO          63     59 IN 2015  Monthly Record: 63
    ALPINE             69     58 IN 1978  Monthly Record: 63
    LAKE CUYAMACA      62     51 IN 2015  Monthly Record: 55
    PALM SPRINGS       73     68 IN 2004  Monthly Record: 70

Thursday:

             FORECAST LOW   RECORD  YEAR

    RIVERSIDE          67     57 IN 1995 Monthly Record: 66
    LAKE ELSINORE      62     56 IN 1986 Monthly Record: 61
    ALPINE             69     55 IN 1990 Monthly Record: 63
    IDYLLWILD          64     43 IN 2017 Monthly Record: 50
    LAKE CUYAMACA      64     53 IN 2017 Monthly Record: 55
    CAMPO              58     51 IN 1951 Monthly Record: 58
    PALM SPRINGS       74     64 IN 2017 Monthly Record: 70
    BORREGO            70     64 IN 2013 Monthly Record: 70

Friday:


             FORECAST LOW   RECORD  YEAR

    RIVERSIDE          67     58 IN 1995 Monthly Record: 66
    LAKE ELSINORE      64     57 IN 1940 Monthly Record: 61
    ALPINE             70     58 IN 2001 Monthly Record: 63
    IDYLLWILD          66     45 IN 2017 Monthly Record: 50
    LAKE CUYAMACA      64     51 IN 2017 Monthly Record: 55
    PALM SPRINGS       75     69 IN 1932 Monthly Record: 70
    THERMAL            69     68 IN 1989 Monthly Record: 69
    BORREGO            71     65 IN 2017 Monthly Record: 70

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Wednesday evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.

     Heat Advisory until 8 PM PDT Friday for Orange County Coastal
     Areas-Orange County Inland Areas-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Coastal Areas-San Diego County Valleys-Santa Ana Mountains
     and Foothills.

     Heat Advisory from 10 AM Wednesday to 8 PM PDT Friday for
     Riverside County Mountains-San Bernardino County Mountains-
     San Diego County Mountains.

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

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE/BEACHES...Villafane

NWS San Diego (SGX) Office



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