A nearly stationary boundary combined with heating resulting in an area of thunderstorms with several storms becoming severe. Large hail and a couple of damaging winds reports were received.

Hail in WASHINGTON, IOWA
From 13-MAY-18 13:35:00 to 13-MAY-18 13:35:00 (CST-6)
Location: BRIGHTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported dime to nickel sized hail.

Hail in WASHINGTON, IOWA
From 13-MAY-18 13:37:00 to 13-MAY-18 13:37:00 (CST-6)
Location: WASHINGTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Received an amateur radio report of nickel sized hail six miles southwest of Washington on Highway 1.

Hail in DUBUQUE, IOWA
From 14-MAY-18 00:41:00 to 14-MAY-18 00:41:00 (CST-6)
Location: EPWORTH
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county  emergency manager reported penny sized hail.

Hail in JOHNSON, IOWA
From 14-MAY-18 04:58:00 to 14-MAY-18 04:58:00 (CST-6)
Location: TIFFIN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report was received of penny sized hail.

Hail in JOHNSON, IOWA
From 14-MAY-18 05:00:00 to 14-MAY-18 05:00:00 (CST-6)
Location: CORALVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Received a report from local media of penny sized hail.

Hail in LINN, IOWA
From 14-MAY-18 06:02:00 to 14-MAY-18 06:02:00 (CST-6)
Location: MT VERNON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported hail up to the size of quarters.

Hail in LINN, IOWA
From 14-MAY-18 06:05:00 to 14-MAY-18 06:05:00 (CST-6)
Location: MT VERNON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Received a public report of golf ball sized hail.  The time was estimated based on radar and another nearby hail report.

Hail in LINN, IOWA
From 14-MAY-18 06:08:00 to 14-MAY-18 06:08:00 (CST-6)
Location: MT VERNON
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported hail up to the size of half dollars.

Hail in JONES, IOWA
From 14-MAY-18 06:21:00 to 14-MAY-18 06:21:00 (CST-6)
Location: MORLEY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported hail up to the size of quarters. The time was estimated by radar.

Hail in SCOTT, IOWA
From 14-MAY-18 14:28:00 to 14-MAY-18 14:28:00 (CST-6)
Location: LE CLAIRE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported hail up to the size of nickels.  The hail started as pea sized and increased to the size of nickels before it quit.

Hail in HENRY, IOWA
From 14-MAY-18 19:45:00 to 14-MAY-18 19:50:00 (CST-6)
Location: SWEDESBURG
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report was received of hail up to the size of nickels that last for 5 minutes.

Thunderstorm Wind in WASHINGTON, IOWA
From 13-MAY-18 13:33:00 to 13-MAY-18 13:33:00 (CST-6)
Location: WASHINGTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A delayed report was received from the public of a small tree down.

Thunderstorm Wind in HENRY, IOWA
From 14-MAY-18 20:15:00 to 14-MAY-18 20:15:00 (CST-6)
Location: MT UNION
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported wind gusts 4 WSW of Mount Union of 50 up to 60 mph. Hail up to the size of pennies was also reported.