An expanding upper-level ridge across the southern and central U.S. pushed heat into the region, as moisture pooled just ahead of an advancing frontal zone.  The combination of heat and higher dewpoints resulted in afternoon and early evening heat indices from 100 to 115 degrees.

Excessive Heat in HANSON, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 16:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 110 degrees was reached at South Dakota Road Weather Information System site SD502 near Alexandria.

Excessive Heat in HUTCHINSON, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 16:30:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 110 degrees was reached at the South Dakota State University Mesonet site PSTS2 at Parkston and 106 degrees at South Dakota Road Weather Information System site SD570 near Tripp.

Excessive Heat in YANKTON, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 18:30:00 (CST-6)
Reported by: AWOS

A maximum heat index of 110 degrees was reached at Automated Weather Observing System site KYKN at Yankton.

Excessive Heat in TURNER, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 18:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 107 degrees was reached at South Dakota Road Weather Information System site SD615 4 miles east of Irene.

Excessive Heat in KINGSBURY, SOUTH DAKOTA
From 19-AUG-23 11:00:00 to 19-AUG-23 16:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 111 degrees was reached at South Dakota Road Weather Information System site SD504 near Arlington.

Heat in BEADLE, SOUTH DAKOTA
From 19-AUG-23 11:00:00 to 19-AUG-23 14:00:00 (CST-6)
Reported by: ASOS

A maximum heat index of 102 degrees was reached at the Automated Surface Observing System site KHON at Huron and South Dakota Road Weather Information System site SD515 near Cavour.

Excessive Heat in UNION, SOUTH DAKOTA
From 19-AUG-23 12:30:00 to 19-AUG-23 19:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 111 degrees was reached at South Dakota Road Weather Information System site SD550 in North Sioux City.

Excessive Heat in LINCOLN, SOUTH DAKOTA
From 19-AUG-23 13:30:00 to 19-AUG-23 18:30:00 (CST-6)
Reported by: AWOS

A maximum heat index of 111 degrees was reached at Automated Weather Observing System site KY14 in Tea and 110 degrees at K7G9 near Canton.

Excessive Heat in MINNEHAHA, SOUTH DAKOTA
From 19-AUG-23 12:30:00 to 19-AUG-23 17:30:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 111 degrees was reached at the South Dakota State University Mesonet site BTCS2 near Baltic and 109 degrees at CTNS2 near Colton and SFWS2 10 miles west-southwest of Sioux Falls.

Heat in AURORA, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 15:00:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 100 degrees was reached at South Dakota State University Mesonet site WTES2 near White Lake and South Dakota Road Weather Information System site SD553 near Plankinton.

Heat in GREGORY, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 15:00:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 100 degrees was reached at personal weather station 7896D near Bonesteel.

Heat in CHARLES MIX, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 15:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 103 degrees was reached at South Dakota Road Weather Information System site SD622 8 miles east of Wagner, 102 degrees at a personal weather station EW6057 in Platte, and 100 degrees at the RAWS site RLAS2 3 miles west of Geddes.

Excessive Heat in CLAY, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 16:30:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 108 degrees was reached at the South Dakota State University Mesonet site BFMS2 7 miles west-southwest of Beresford.

Excessive Heat in LAKE, SOUTH DAKOTA
From 19-AUG-23 12:30:00 to 19-AUG-23 17:00:00 (CST-6)
Reported by: AWOS

A maximum heat index of 111 degrees was reached at Automated Weather Observing System site KMDS at Madison.

Excessive Heat in MCCOOK, SOUTH DAKOTA
From 19-AUG-23 14:30:00 to 19-AUG-23 17:30:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 108 degrees was reached at South Dakota Road Weather Information System site SD620 3 miles north of Dolton and 105 degrees 3 miles southeast of Montrose.

Excessive Heat in BROOKINGS, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 16:30:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 107 degrees was reached at the South Dakota State University Mesonet site BKMS2 near Brookings and personal weather station GW0796 at Elkton, as well as 106 degrees at Volga.

Excessive Heat in BON HOMME, SOUTH DAKOTA
From 19-AUG-23 14:00:00 to 19-AUG-23 18:00:00 (CST-6)
Reported by: Department of Highways

A maximum heat index of 106 degrees was reached at South Dakota Road Weather Information System site SD571 5 miles east-southeast of Tyndall.

Excessive Heat in DAVISON, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 15:00:00 (CST-6)
Reported by: ASOS

A maximum heat index of 107 degrees was reached at Automated Surface Observing System site KMHE at Mitchell.

Excessive Heat in SANBORN, SOUTH DAKOTA
From 19-AUG-23 12:00:00 to 19-AUG-23 15:00:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 106 degrees was reached at the South Dakota State University Mesonet site LCMS2 near Letcher and 103 degrees at South Dakota Road Weather Information System site SD527 3 miles east-southeast of Forestburg.

Excessive Heat in MINER, SOUTH DAKOTA
From 19-AUG-23 13:00:00 to 19-AUG-23 16:00:00 (CST-6)
Reported by: Mesonet

A maximum heat index of 105 degrees was reached at South Dakota Road Weather Information System site SD597 near Howard.

Excessive Heat in MOODY, SOUTH DAKOTA
From 19-AUG-23 12:30:00 to 19-AUG-23 17:00:00 (CST-6)
Reported by: AWOS

A maximum heat index of 107 degrees was reached at Automated Weather Observing System site K4P3 near Flandreau and South Dakota State University Mesonet site FLNS2.