A few supercell thunderstorms developed ahead of a warm front advancing into the forecast area, where they produced gusty winds, heavy rain, and hail up to 3 inches in diameter. Storms initially developed as more discrete supercells early in the evening, with the storm that went through Burlington being one of the more intense storms. Rainfall amounts reached 2 inches or more in some areas, as the anomalously moist environment favored excessive rainfall that lead to flash flooding. The La Moine River near Colmar also raised to Minor Flood stage due to the heavy rain.

Hail in DES MOINES, IOWA
From 09-JUL-21 18:20:00 to 09-JUL-21 18:35:00 (CST-6)
Location: BURLINGTON ARPT
Magnitude: 1.50 
Reported by: Trained Spotter

Ping pong ball sized hail.

Hail in HENRY, IOWA
From 09-JUL-21 17:30:00 to 09-JUL-21 17:45:00 (CST-6)
Location: MT UNION
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Ping pong ball sized hail.

Hail in DES MOINES, IOWA
From 09-JUL-21 18:25:00 to 09-JUL-21 18:40:00 (CST-6)
Location: BURLINGTON ARPT
Magnitude: 2.50 
Reported by: Public

Tennis ball sized hail.

Hail in DES MOINES, IOWA
From 09-JUL-21 18:19:00 to 09-JUL-21 18:19:00 (CST-6)
Location: WEST BURLINGTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, IOWA
From 09-JUL-21 16:56:00 to 09-JUL-21 16:56:00 (CST-6)
Location: WASHINGTON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Received a public report of three quarter inch hail.

Hail in HENRY, IOWA
From 09-JUL-21 17:51:00 to 09-JUL-21 17:51:00 (CST-6)
Location: NEW LONDON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported dime to quarter size hail.

Hail in DES MOINES, IOWA
From 09-JUL-21 18:20:00 to 09-JUL-21 18:20:00 (CST-6)
Location: SPRING GROVE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LEE, IOWA
From 09-JUL-21 19:54:00 to 09-JUL-21 19:54:00 (CST-6)
Location: DONNELLSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in DES MOINES, IOWA
From 09-JUL-21 18:30:00 to 09-JUL-21 18:30:00 (CST-6)
Location: BURLINGTON ARPT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in LEE, IOWA
From 09-JUL-21 20:18:00 to 09-JUL-21 20:18:00 (CST-6)
Location: KEOKUK
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reports a tree down near 16th street. There are also several 6 to 10 inch tree limbs down.

Hail in DES MOINES, IOWA
From 09-JUL-21 18:20:00 to 09-JUL-21 18:35:00 (CST-6)
Location: WEST BURLINGTON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Golf ball sized hail.

Hail in HENRY, IOWA
From 09-JUL-21 17:49:00 to 09-JUL-21 17:51:00 (CST-6)
Location: NEW LONDON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported nickel size hail fell for 2 minutes.

Hail in HENRY, IOWA
From 09-JUL-21 17:10:00 to 09-JUL-21 17:25:00 (CST-6)
Location: SWEDESBURG
Magnitude: 1.75 
Reported by: Trained Spotter

Golf ball hail on 218 near Swedesburg. Heavy rain with near zero visibility.