Strong upper level ridge built up over the region from July 25th through 29th. This ushered in much warmer air and higher dewpoints. So heat index values 100+ were reported from July 25th through 29th. The hottest days were July 27th, 28th and 29th, so an excessive heat warning was issued for portions of northeast/east central Missouri and west central/southwest Illinois. At least 50 people were seen in hospital emergency room departments during this three day period in St. Louis County/City for heat-related illnesses.

Excessive Heat in LEWIS, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the mid to upper 90s each day. Heat index values as high as 110 both days.

Excessive Heat in JEFFERSON, MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Excessive heat across the county with highs in the mid to upper 90s degrees each day. Heat index values as high as 110 each day.

Excessive Heat in STE. GENEVIEVE, MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Excessive heat across the county with highs in the mid to upper 90s degrees each day. Heat index values as high as 110 each day.

Excessive Heat in KNOX, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the mid to upper 90s each day. Heat index values as high as 110 both days.

Excessive Heat in LINCOLN, MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the mid to upper 90s degrees each day. Heat index values as high as 110 each day.

Excessive Heat in SHELBY, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the upper 90s to 102 degrees each day. Heat index values as high as 110 both days.

Excessive Heat in MARION, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the upper 90s to 102 degrees each day. Heat index values as high as 110 both days.

Excessive Heat in RALLS, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the upper 90s to 102 degrees each day. Heat index values as high as 110 both days.

Excessive Heat in PIKE, MISSOURI
From 27-JUL-23 09:00:00 to 28-JUL-23 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Excessive heat across the county with highs in the upper 90s to 102 degrees each day. Heat index values as high as 110 both days.

Excessive Heat in ST. LOUIS, MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Excessive heat across the county with highs in the upper 90s to 101 degrees each day. Heat index values as high as 110 each day. At least 25 people were seen in hospital emergency room departments during this three day period in St. Louis County for heat-related illnesses.

Excessive Heat in ST. LOUIS (C), MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Excessive heat across the county with highs in the upper 90s to 101 degrees each day. Heat index values as high as 110 each day. At least 25 people were seen in hospital emergency room departments during this three day period in St. Louis City for heat-related illnesses.

Excessive Heat in ST. CHARLES, MISSOURI
From 27-JUL-23 09:00:00 to 29-JUL-23 16:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Excessive heat across the county with highs in the mid to upper 90s degrees each day. Heat index values as high as 110 each day.