A strong push of very warm air moved into the state on the afternoon of the 6th with high temperatures reaching well into the 90s over the west half of the state.  Dewpoint readings rose to the low 60s.  The atmosphere became unstable, but was capped through much of the day.  By the evening, a cold front began to push into the northwest part of the state.  Thunderstorms developed ahead of the front and became severe quite quickly.  There was around 3000 J/kg of elevated CAPE available, though the shear was weak with 20 to 30 kts of effective shear.  The moisture was relatively limited.  Though there was 1.25 inches of precipitable water in the sounding, the low levels were quite dry.  Downdraft CAPE was high, with 1200 to 1700 J/kg available and the freezing level was quite high for early May, around 13,000 feet.  The available CAPE in the -10 to -30 C layer of the atmosphere was between 300 and 600 J/kg.  Thunderstorms developed ahead of the cold front during the evening and produced hail and high winds.  Golf ball to two inch diameter hail fell in Calhoun and Sac Counties.  Winds gusts to nearly 65 MPH were observed on the back side of the storms in Carroll County in Carroll.  As the thunderstorms weakened and collapsed, they produced high winds.  An estimated wind gust of 70 MPH tore out a 26 x 48 inch tunnel and a twisted it and a play set was blown over north of Lytton in Calhoun County.  The thunderstorms continued to collapse and head northeast.  Winds gusted to 77 MPH at the Algona Airport.

Thunderstorm Wind in CALHOUN, IOWA
From 07-MAY-14 21:18:00 to 07-MAY-14 21:18:00 (CST-6)
Location: JOLLEY
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in KOSSUTH, IOWA
From 07-MAY-14 23:15:00 to 07-MAY-14 23:15:00 (CST-6)
Location: ALGONA MUNI ARPT
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in CARROLL, IOWA
From 07-MAY-14 21:31:00 to 07-MAY-14 21:31:00 (CST-6)
Location: CARROLL
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Thunderstorm Wind in POCAHONTAS, IOWA
From 07-MAY-14 21:25:00 to 07-MAY-14 21:25:00 (CST-6)
Location: FONDA
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A county sheriff reported straight line winds blew the roof off of a shed.

Thunderstorm Wind in KOSSUTH, IOWA
From 07-MAY-14 23:20:00 to 07-MAY-14 23:20:00 (CST-6)
Location: WHITTEMORE
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in KOSSUTH, IOWA
From 07-MAY-14 23:25:00 to 07-MAY-14 23:25:00 (CST-6)
Location: ALGONA MUNI ARPT
Magnitude: 67.00 MG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in KOSSUTH, IOWA
From 07-MAY-14 23:35:00 to 07-MAY-14 23:35:00 (CST-6)
Location: ALGONA MUNI ARPT
Magnitude: 57.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: AWOS

Hail in WEBSTER, IOWA
From 08-MAY-14 01:20:00 to 08-MAY-14 01:20:00 (CST-6)
Location: (FOD)FT DODGE MUNI A
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in WEBSTER, IOWA
From 08-MAY-14 01:20:00 to 08-MAY-14 01:20:00 (CST-6)
Location: (FOD)FT DODGE MUNI A
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tree branches were blown down.

Thunderstorm Wind in WRIGHT, IOWA
From 08-MAY-14 01:20:00 to 08-MAY-14 01:20:00 (CST-6)
Location: CLARION ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Hail in SAC, IOWA
From 07-MAY-14 20:59:00 to 07-MAY-14 20:59:00 (CST-6)
Location: LYTTON
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CALHOUN, IOWA
From 07-MAY-14 21:10:00 to 07-MAY-14 21:10:00 (CST-6)
Location: LAVINIA
Magnitude: 2.00 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in WRIGHT, IOWA
From 08-MAY-14 01:42:00 to 08-MAY-14 01:42:00 (CST-6)
Location: EAGLE GROVE
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large tree limb 2 feet in diameter snapped off and fell on two cars.

Thunderstorm Wind in CALHOUN, IOWA
From 07-MAY-14 22:58:00 to 07-MAY-14 22:58:00 (CST-6)
Location: LYTTON
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Public

A 26 x 48 tunnel was ripped from the ground and twisted.  A playset was blown over.  Winds were estimated to be 70 MPH.