Strong warm air advection took place over Iowa during the overnight hours of the 14th into the morning of the 15th.  A low level jet of about 30 kts set up during the late night hours.  Being it was during the night, much of the convection was elevated, however the lifted index fell to the zero to -3 C. range with about 1000 J/kg of CAPE.  Downdraft CAPE war around 1100 J/kg as the airmass was not saturated.  CAPE in the -10 to -30 C. layer was only 200 J/kg, so in spite of the low freezing level, 10,000 to 10,500 feet, hail was not a major player.  The high winds were the primary mode of severe weather.  The LCL height was quite high, around 2000 meters.  In spite of that, a tornado touched down briefly in Humboldt County, causing minor damage.  Funnel clouds were reported in Wright County, however no touchdowns occurred.  Two clusters of storms developed and moved east across northern Iowa.  The two actually followed nearly the same track, giving two rounds of thunderstorms to nearly the same areas.  Numerous reports of high winds were received, many in the 60 to 65 MPH range.  One report from Steamboat Rock, in Hardin County, by an RWIS site.

Thunderstorm Wind in GRUNDY, IOWA
From 15-JUN-08 02:10:00 to 15-JUN-08 02:10:00 (CST-6)
Location: GRUNDY CENTER
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Awnings blown off of a business in Grundy Center.

Thunderstorm Wind in HAMILTON, IOWA
From 15-JUN-08 01:30:00 to 15-JUN-08 01:30:00 (CST-6)
Location: WILLIAMS
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Grain bin on the road and power lines down.  Possible tornado damage.

Thunderstorm Wind in HARDIN, IOWA
From 15-JUN-08 01:40:00 to 15-JUN-08 01:40:00 (CST-6)
Location: IOWA FALLS
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Trees damaged with one 18 inch diameter tree falling on a van.

Thunderstorm Wind in WRIGHT, IOWA
From 15-JUN-08 01:00:00 to 15-JUN-08 01:00:00 (CST-6)
Location: GOLDFIELD
Magnitude: 57.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees were blown down with many uprooted.

Thunderstorm Wind in WEBSTER, IOWA
From 15-JUN-08 01:02:00 to 15-JUN-08 01:02:00 (CST-6)
Location: VINCENT
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large trees blown down on main street.

Thunderstorm Wind in HARDIN, IOWA
From 15-JUN-08 01:57:00 to 15-JUN-08 01:57:00 (CST-6)
Location: STEAMBOAT ROCK
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Wind gust measured by the Steamboat Rock RWIS site.

Tornado in HUMBOLDT, IOWA
From 15-JUN-08 00:49:00 to 15-JUN-08 00:51:00 (CST-6)
Location: THOR
Tornado F-scale: EF0
Property damage: 10.00K
Crop damage: 1.00K
Reported by: Trained Spotter

Spotter observed power lines or transformers blowing out.

Hail in PALO ALTO, IOWA
From 14-JUN-08 23:48:00 to 14-JUN-08 23:48:00 (CST-6)
Location: RUTHVEN
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in HUMBOLDT, IOWA
From 15-JUN-08 01:18:00 to 15-JUN-08 01:18:00 (CST-6)
Location: LIVERMORE
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Nickel to quarter size hail was reported.

Thunderstorm Wind in GRUNDY, IOWA
From 15-JUN-08 02:22:00 to 15-JUN-08 02:22:00 (CST-6)
Location: CONRAD
Magnitude: 53.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel size hail reported as well.

Thunderstorm Wind in TAMA, IOWA
From 15-JUN-08 02:30:00 to 15-JUN-08 02:30:00 (CST-6)
Location: GLADBROOK
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large trees down.

Thunderstorm Wind in WRIGHT, IOWA
From 15-JUN-08 01:15:00 to 15-JUN-08 01:15:00 (CST-6)
Location: CLARION
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in HARDIN, IOWA
From 15-JUN-08 01:40:00 to 15-JUN-08 01:40:00 (CST-6)
Location: IOWA FALLS
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Six to eight tree limbs fell on a vehicle.

Thunderstorm Wind in WRIGHT, IOWA
From 15-JUN-08 01:05:00 to 15-JUN-08 01:05:00 (CST-6)
Location: EAGLE GROVE
Magnitude: 57.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees were downed with several uprooted.  Numerous reports of a funnel cloud in the area.

Thunderstorm Wind in HARDIN, IOWA
From 15-JUN-08 01:38:00 to 15-JUN-08 01:38:00 (CST-6)
Location: IOWA FALLS
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Widespread small tree limb damage and one 8 inch diameter limb snapped.  Tree was snapped at Linden and Indiana Ave.

Thunderstorm Wind in BLACK HAWK, IOWA
From 15-JUN-08 02:45:00 to 15-JUN-08 02:45:00 (CST-6)
Location: WASHBURN
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong winds have spread to Washburn as well.

Thunderstorm Wind in HARDIN, IOWA
From 15-JUN-08 01:35:00 to 15-JUN-08 01:35:00 (CST-6)
Location: ALDEN
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Grain bin in the middle of the road on Highway D25.

Thunderstorm Wind in BLACK HAWK, IOWA
From 15-JUN-08 02:40:00 to 15-JUN-08 02:40:00 (CST-6)
Location: WATERLOO
Magnitude: 57.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large trees were down in the southern end of Waterloo.  Power lines taken down as well.  Another tree was downed in Evansdale.

Hail in GRUNDY, IOWA
From 15-JUN-08 02:22:00 to 15-JUN-08 02:22:00 (CST-6)
Location: CONRAD
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Trained Spotter