A strong upper level low pressure system lifted northeast out of the southeast U.S. during the day on the 8th.  Surface low pressure was located over northwest Kansas in the morning and tracked northeast into southern Minnesota by the evening.  Moisture was drawn north ahead of the low with precipitable water values rising to around 1.3 inches.  Surface dewpoints rose into the low to mid 60s.  The atmosphere was unstable with the lifted index falling to -6 C and CAPE values around 2000 J/kg.  Downdraft CAPE was in the 800 to 1200 J/kg range.  The flow was around 40 kts at 850 mb from the south-southwest.  The atmosphere was moderately sheared with 30 to 40 kts of effective shear.  The LCL was relatively high around 1250 meters.  CAPE in the -10 to -30 C layer of the atmosphere was around 400 J/kg with the freezing level only 12,000 feet.  Thunderstorms developed over west central into northwest Iowa along a cold front that pushed into the state.  The storms produced winds of up to 70 MPH in Kossuth County near Algona.  Another storm produced quarter size hail in Carroll County west of Willey.  A severe thunderstorm developed over south central Iowa southwest of the Des Moines metro area.  This storm produced large hail with a swath of hail extending form Madison County through the Des Moines area before it weakened.  There were numerous reports of golf ball size hail.  Baseball size hail fell on the northwest side of the Metro east of Urbandale.  The storm also produced gusty winds in the 55 to 60 mph range reported at a few locations.

Hail in MADISON, IOWA
From 08-MAY-14 17:40:00 to 08-MAY-14 17:40:00 (CST-6)
Location: PATTERSON
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A wind gust to 57 MPH was also measured.

Hail in WARREN, IOWA
From 08-MAY-14 17:56:00 to 08-MAY-14 17:56:00 (CST-6)
Location: NORWALK
Magnitude: 1.50 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds gusts to 60 MPH as well.

Hail in POLK, IOWA
From 08-MAY-14 18:11:00 to 08-MAY-14 18:11:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.50 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Beaverdale area report.

Hail in POLK, IOWA
From 08-MAY-14 18:05:00 to 08-MAY-14 18:05:00 (CST-6)
Location: LOVINGTON
Magnitude: 2.75 
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Public

Reported near the intersection of Merle Hay Road and Meredith Drive.

Hail in POLK, IOWA
From 08-MAY-14 18:00:00 to 08-MAY-14 18:00:00 (CST-6)
Location: WEST DES MOINES
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Located at the southeast corner of 63rd and Grand.

Hail in POLK, IOWA
From 08-MAY-14 18:05:00 to 08-MAY-14 18:05:00 (CST-6)
Location: CLOVER HILLS
Magnitude: 2.00 
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Public

Hail in POLK, IOWA
From 08-MAY-14 18:02:00 to 08-MAY-14 18:02:00 (CST-6)
Location: WEST DES MOINES
Magnitude: 2.00 
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Public

Hail in POLK, IOWA
From 08-MAY-14 18:08:00 to 08-MAY-14 18:08:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in POLK, IOWA
From 08-MAY-14 18:15:00 to 08-MAY-14 18:15:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.50 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-MAY-14 18:15:00 to 08-MAY-14 18:15:00 (CST-6)
Location: SWANWOOD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in POLK, IOWA
From 08-MAY-14 18:04:00 to 08-MAY-14 18:04:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 2.00 
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in POLK, IOWA
From 08-MAY-14 18:03:00 to 08-MAY-14 18:03:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-MAY-14 18:10:00 to 08-MAY-14 18:10:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-MAY-14 18:05:00 to 08-MAY-14 18:05:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, IOWA
From 08-MAY-14 18:20:00 to 08-MAY-14 18:20:00 (CST-6)
Location: ANKENY
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Eighteen inch diameter tree split.

Thunderstorm Wind in KOSSUTH, IOWA
From 08-MAY-14 12:40:00 to 08-MAY-14 12:40:00 (CST-6)
Location: ALGONA
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Wind speed was estimated by the Emergency Manager.

Hail in CARROLL, IOWA
From 08-MAY-14 15:47:00 to 08-MAY-14 15:47:00 (CST-6)
Location: WILLEY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MADISON, IOWA
From 08-MAY-14 17:35:00 to 08-MAY-14 17:35:00 (CST-6)
Location: EAST PERU
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in POLK, IOWA
From 08-MAY-14 18:07:00 to 08-MAY-14 18:07:00 (CST-6)
Location: URBANDALE
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in POLK, IOWA
From 08-MAY-14 18:05:00 to 08-MAY-14 18:05:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in POLK, IOWA
From 08-MAY-14 18:09:00 to 08-MAY-14 18:09:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.50 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in WARREN, IOWA
From 08-MAY-14 17:56:00 to 08-MAY-14 17:56:00 (CST-6)
Location: NORWALK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimated 60 MPH wind gust.

Hail in POLK, IOWA
From 08-MAY-14 18:08:00 to 08-MAY-14 18:08:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Employee

Reported at Holy Trinity School in Urbandale.

Hail in POLK, IOWA
From 08-MAY-14 18:11:00 to 08-MAY-14 18:11:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.00 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Reported at the I-80 and Merle Hay Road exchange.

Hail in POLK, IOWA
From 08-MAY-14 18:11:00 to 08-MAY-14 18:11:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 1.50 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-MAY-14 18:14:00 to 08-MAY-14 18:14:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.25 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Public

Hail in POLK, IOWA
From 08-MAY-14 18:10:00 to 08-MAY-14 18:10:00 (CST-6)
Location: LOVINGTON
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter