Excessive Heat in California, September 1 to 9, 2022

Name: Excessive Heat in California, September 1 to 9, 2022
Start: 2022-09-01T00:00
End: 2022-09-09T23:59
Location: California

September 1 to 9, 2022 · NWS SGX · 13 events in 13 counties and zones

Early September heat starting in August.

Where it happened

Every event with a place to put it; 13 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 13

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS SGX wrote it up.

Early September heat starting in August.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Diego, CA wrote its last area forecast discussion before the first event at Aug 31, 8:19 PM PST, 3 hours 41 minutes earlier.

Area forecast discussion, Aug 31, 8:19 PM PST, 3 hours 41 minutes before

Area Forecast Discussion
National Weather Service San Diego CA
919 PM PDT Wed Aug 31 2022

.SYNOPSIS...
A heat wave will continue into early next week. The return of
some monsoonal moisture is expected to bring a slight chance of
thunderstorms mainly to the mountains Friday into next week. Skies
will be mostly clear, with a few high clouds and periods of
patchy low clouds near the coast.

&&

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

.Evening Update...

It was quite a hot day out there today, with many locations
breaking or tying their daily temperature records. Anaheim (at 106
degrees) not only broke their high temperature record for the
day, but also broke their all-time high temperature record for the
month of August. The previous all-time August record was 105
degrees set back on August 18, 2020.

Temperatures on Thursday will more or less be the same as today
west of the mountains. Increasing moisture in the lower deserts
may shave a few degrees off their high temperature on Thursday
compared to today, but it will surely still feel just as hot as
today due to the increased humidity.

Slight cooling is expected west of the mountains on Friday due to
the development of a coastal eddy, but temperatures will still
remain quite warm. Temperatures will bump right back up on
Saturday as that coastal eddy weakens. Sunday and Monday still
look to be the hottest days during this heat wave.

The forecast remains on track, with Excessive Heat Warnings in
place for all areas. No changes were made to the forecast this
evening. See the previous discussion below for more details on the
heat wave and thunderstorm potential.

.Previous Discussion issued at 1:34PM...

The heat wave is still on track to continue into next week. Coastal
temperatures are expected to be a few degrees cooler Thursday and
Friday with the development of a coastal eddy. With the eddy, low
cloud coverage is expected to increase Friday morning. A low level
moisture influx into the lower deserts will act to moderate
temperatures there Thursday and Friday. That being said, highs there
will be mostly above 108 degrees. Even with the slightly cooler
temperatures, highs will still be 5 to 10 degrees above average
across the forecast area.

Saturday through early next week the high pressure over the Great
Basin remains in place and is expected to strengthen for Saturday
and Sunday. High temperatures Saturday through Monday will be 15 to
20 degrees warmer than average for the coast and western valleys, 10
to 15 degrees above average for the Inland Empire and eastern
valleys in San Diego, 7 to 10 degrees above average in the
mountains, and 5 to 10 degrees above average in the deserts.
Excessive heat may continue into Tuesday, with gradual cooling
expected for the end of next week. In addition to the daytime heat,
nights will be quite warm as well with low temperatures for the
coast and valleys mostly in the 70s to around 80 with the warmer
lows near the coastal foothills. In the lower deserts, low
temperatures will mostly be in the mid 80s to lower 90s.

At the coast, the potential development of a coastal eddy late in
the weekend is adding some uncertainty to the high temperature
forecast. NBM guidance for coastal areas is showing an 8 degree
temperature spread between the cooler and warmer high temperature
solutions. That uncertainty in high temperatures continues into
Tuesday for coastal areas.

Mid level moisture and easterly flow could bring more afternoon
clouds to the mountains beginning on Thursday with small chances for
an isolated shower or thunderstorm in the higher mountains during
the afternoon and early evening. Slight chances of thunderstorms in
the mountains each afternoon and early evening, possibly drifting
into the adjacent inland valleys will continue into next week.

&&

.AVIATION...
010400Z...FEW with bases near 1000 FT MSL will be possible late
tonight near the immediate coast, though cigs are not expected to
develop. On Friday, SCT Cu possible in the mountains, with bases
around 10,000 FT MSL. Otherwise...mostly clear through Thursday.

&&

.MARINE...
No hazardous marine weather is expected through Monday.

&&&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 8 PM PDT Monday for Apple and
     Lucerne Valleys-Coachella Valley-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 Deserts-San Diego County
     Mountains-San Diego County Valleys-San Gorgonio Pass Near
     Banning-Santa Ana Mountains and Foothills.

PZ...None.

&&

PUBLIC...Connolly(update)/CO(previous discussion)
AVIATION/MARINE...Brotherton

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

13 excessive heat. Local standard time, as filed.

Excessive Heat, San Diego County Coastal Areas

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Diego County Coastal Areas forecast zone
Reported by: ASOS
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

The ASOS at San Diego International Airport observed daily highs reaching at least the middle to upper 80s through much of early September, with several days reaching the lower to middle 90s. The highest daily maximum temperature of 95 degrees occurred on the afternoon of Saturday September 3rd, with a high of 94 occurring on Thursday, September 8th. Highs on Saturday, September 10th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Orange County Coastal

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Orange County Coastal forecast zone
Reported by: ASOS
Coordinates: 33.677, -117.776 (the zone’s center; the record gives no point)

The ASOS at John Wayne International Airport observed daily highs reaching at least the lower to middle 90s through much of early September, with several days ranging from 97 to 106 degrees. The highest daily maximum temperature of 106 degrees occurred on the afternoon of Sunday September 4th, with a high of 102 occurring on Thursday, September 8th. Highs on Saturday, September 10th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Diego County Valleys

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Diego County Valleys forecast zone
Reported by: ASOS
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

The ASOS at Ramona Airport observed daily highs ranging from 100 to 107 degrees through much of early September. The highest daily maximum temperature of 107 degrees occurred on the afternoon of Wednesday September 7th, with a high of 104 degrees occurring on all of the September 1st, 4th, and 6th. Highs on Saturday, September 10th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Bernardino and Riverside County Valleys - the Inland Empire

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Bernardino and Riverside County Valleys - the Inland Empire forecast zone
Reported by: ASOS
Coordinates: 34.293, -116.086 (the zone’s center; the record gives no point)

The ASOS at Riverside Airport observed daily highs ranging from 100 to 110 degrees through much of early September. The highest daily maximum temperature of 110 degrees occurred on the afternoon of Sunday, September 4th, with highs of 107-109 also occurring on several days during this time. Highs on Saturday, September 10th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Orange County Inland

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Orange County Inland forecast zone
Reported by: ASOS
Coordinates: 33.677, -117.776 (the zone’s center; the record gives no point)

The ASOS at Fullerton Airport observed daily highs ranging from the middle to upper 90s through much of early September, with several days also exceeding 100 degrees for a daily high. The highest daily maximum temperature of 111 degrees occurred on the afternoon of Sunday, September 4th, with a high of 103 occurring on the 3rd and 8th of September. Highs on Saturday, September 10th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Diego County Mountains

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Diego County Mountains forecast zone
Reported by: Mesonet
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

The JULC1 observation site in Julian observed daily highs ranging from the upper 80s to the middle and upper 90s through much of early September. The highest daily maximum temperature of 98 degrees occurred on the afternoon of Tuesday, September 6th, with a high of 95 occurring on the 1st of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Riverside County Mountains

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Riverside County Mountains forecast zone
Reported by: Mesonet
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

The NZAC1 observation site in Anza observed daily highs ranging from the lower 90s to upwards of 101 degrees through much of early September. The highest daily maximum temperature of 101 degrees occurred on the afternoon of Thursday, September 1st, with a high of 99 degrees occurring on the 6th of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Bernardino County Mountains

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Bernardino County Mountains forecast zone
Reported by: AWOS
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

The Big Bear City Airport observed daily highs ranging from the lower to middle 80s through much of early September. The highest daily maximum temperature of 86 degrees occurred on the afternoon of Tuesday, September 6th, with a high of 84 degrees occurring on the 2nd of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Santa Ana Mountains and Foothills

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Santa Ana Mountains and Foothills forecast zone
Reported by: RAWS
Coordinates: 33.483, -116.847 (the zone’s center; the record gives no point)

The El Cariso RAWS site observed daily highs ranging from the middle 90s to upwards of 107 degrees through much of early September. The highest daily maximum temperature of 107 degrees occurred on the afternoon of Tuesday, September 6th, with a high of 106 degrees occurring on the 1st and 5th of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Gorgonio Pass Near Banning

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Gorgonio Pass Near Banning forecast zone
Reported by: RAWS
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

The Beaumont AWOS site observed daily highs ranging from the upper 90s to upwards of 105 degrees through much of early September. The highest daily maximum temperature of 105 degrees occurred on both the afternoons of Thursday, September 1st and Tuesday September 6th, with a high of 102 degrees occurring on both the 4th and 5th of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Apple and Lucerne Valleys

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Apple and Lucerne Valleys forecast zone
Reported by: Mesonet
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

The SDAPL observation site in Apple Valley observed daily highs ranging from the upper 90s to upwards of 109 degrees through much of early September. The highest daily maximum temperature of 109 degrees occurred on the afternoons of Thursday, September 1st, Friday September 2nd, and Tuesday September 6th, with a high of 105 degrees occurring on both the 3rd of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, Coachella Valley

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: Coachella Valley forecast zone
Reported by: ASOS
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

The Palm Springs International Airport observed daily highs ranging from 106 degrees to upwards of 114 degrees through much of early September. The highest daily maximum temperature of 114 degrees occurred on the afternoon of Tuesday September 6th, with a high of 113 degrees occurring on both the 5th of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

Excessive Heat, San Diego County Deserts

When: September 1, 12:00 AM PST to September 9, 11:59 PM PST
Where: San Diego County Deserts forecast zone
Reported by: Mesonet
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

The SDOCL observation site in Ocotillo Wells observed daily highs ranging from 103 degrees to upwards of 116 degrees through much of early September. The highest daily maximum temperature of 116 degrees occurred on the afternoon of Tuesday September 6th, with a high of 115 degrees occurring on both the 5th of September. Highs on Friday, September 9th were significantly cooler due to clouds and rain associated with the approach of Hurricane Kay, which ended the heat wave.

What these are

Excessive Heat: Heat at or above the local excessive heat warning criteria, or heat that caused deaths.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2022 Every state in 2022 This day in weather history Warnings in California, September 2022

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 1051002, 1051003, 1051004, 1051005, 1051006, 1051007, 1051008, 1051009, 1051010, 1051011, 1051012, 1051013, 1051014.