A weak boundary was located across Iowa during the afternoon and evening of the 16th, embedded in a northwest flow regime.  The airmass became quite unstable over western into north central Iowa with CAPE in the 3000 to 5000 J/kg range and lifted indices in the -7 to -10 C range.  Shear was relatively weak, 20-25 kts.  There was significant downdraft CAPE available in the 1000 to 1300 J/kg range, with available CAPE in the -10 to -30 C layer of the atmosphere of 700 to 1000 J/kg.  Moisture was transported into the state with precipitable water values reaching 1.25 to 1.5 inches by mid afternoon.  The airmass was quite warm, with the freezing level around 14,500 feet.  Scattered thunderstorms developed by mid to late afternoon from southeast Minnesota, across northwest Iowa, into eastern Nebraska.  Scattered severe weather occurred during the very late afternoon and evening hours.  Hail was reported with some of the storms, up to 1.5 inches in diameter.  High winds from some of the storms produced scattered tree damage as well.  There were two small tornadoes reported.  One was in Franklin County, the other on Hancock County.  Both of these were only on the ground briefly and caused little damage.  In Cerro Gordo and Hancock Counties, heavy rainfall was observed with 2.5 to 3.5 inches falling from the storms.  No flooding occurred however.  Thunderstorms moved into the Waterloo area.  They were dissipating as they moved in, resulting in high winds, non-thunderstorm, west of town.  Trees were downed by the wind, as well as power lines downed.  Power was out and a large motel sign was damaged by the wind.

Tornado in FRANKLIN, IOWA
From 16-JUL-10 20:22:00 to 16-JUL-10 20:23:00 (CST-6)
Location: CHAPIN
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 1.00K
Reported by: Trained Spotter

Trained spotter reports a tornado between Meservey and Latimer heading southeast.

Funnel Cloud in FRANKLIN, IOWA
From 16-JUL-10 20:27:00 to 16-JUL-10 20:27:00 (CST-6)
Location: ALEXANDER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Funnel cloud was reported about half way to the ground.

Hail in WINNEBAGO, IOWA
From 16-JUL-10 18:18:00 to 16-JUL-10 18:18:00 (CST-6)
Location: LELAND
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Public

A few stones to the size of ping pong balls.  Most were smaller.

Tornado in HANCOCK, IOWA
From 16-JUL-10 19:45:00 to 16-JUL-10 19:46:00 (CST-6)
Location: KLEMME
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 1.00K
Reported by: Public

Public report of a tornado on the ground for 1 to 2 minutes.

Heavy Rain in HANCOCK, IOWA
From 16-JUL-10 18:30:00 to 16-JUL-10 20:06:00 (CST-6)
Location: MILLER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated 3.5 inches of rain had fallen.

High Wind in BLACK HAWK, IOWA
From 16-JUL-10 21:46:00 to 16-JUL-10 21:46:00 (CST-6)
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported trees 2 feet in diameter blown down.

Funnel Cloud in CERRO GORDO, IOWA
From 16-JUL-10 19:57:00 to 16-JUL-10 19:57:00 (CST-6)
Location: MASON CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Funnel cloud report from the south side of Mason City.

Funnel Cloud in HANCOCK, IOWA
From 16-JUL-10 19:47:00 to 16-JUL-10 19:47:00 (CST-6)
Location: KANAWHA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Location estimated of funnel clouds lowering and returning.  The cloud was between Corwith and Kanawa.

Funnel Cloud in HANCOCK, IOWA
From 16-JUL-10 19:01:00 to 16-JUL-10 19:01:00 (CST-6)
Location: CORWITH
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a funnel cloud half way to the ground.

Hail in CERRO GORDO, IOWA
From 16-JUL-10 18:56:00 to 16-JUL-10 18:56:00 (CST-6)
Location: VENTURA
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Fire Department/Rescue

Thunderstorm Wind in WRIGHT, IOWA
From 16-JUL-10 21:00:00 to 16-JUL-10 21:00:00 (CST-6)
Location: ROWAN
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Two to four inch diameter branches down as well as power lines down.

Hail in FRANKLIN, IOWA
From 16-JUL-10 20:30:00 to 16-JUL-10 20:30:00 (CST-6)
Location: CHAPIN
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Trained Spotter

Trained spotter reported half dollar size hail at the intersection of C13 and S34.

Hail in WINNEBAGO, IOWA
From 16-JUL-10 16:50:00 to 16-JUL-10 16:50:00 (CST-6)
Location: BUFFALO CENTER ARPT
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Heavy Rain in CERRO GORDO, IOWA
From 16-JUL-10 19:00:00 to 16-JUL-10 20:26:00 (CST-6)
Location: VENTURA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Report of 2.5 inches of rainfall.

Thunderstorm Wind in WRIGHT, IOWA
From 16-JUL-10 20:45:00 to 16-JUL-10 20:45:00 (CST-6)
Location: SOLBERG
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 16 inch diameter trees down north of Galt.

Hail in HUMBOLDT, IOWA
From 16-JUL-10 22:02:00 to 16-JUL-10 22:02:00 (CST-6)
Location: THOR
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 15.00K
Reported by: Trained Spotter

A trained spotter reported quarter size hail 5.5 miles west of Eagle Grove.

High Wind in BLACK HAWK, IOWA
From 16-JUL-10 21:50:00 to 16-JUL-10 22:50:00 (CST-6)
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in HARDIN, IOWA
From 16-JUL-10 21:45:00 to 16-JUL-10 21:45:00 (CST-6)
Location: BUCKEYE
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 2 to 4 inch diameter branches downed.

Funnel Cloud in WRIGHT, IOWA
From 16-JUL-10 19:39:00 to 16-JUL-10 19:39:00 (CST-6)
Location: FLORENCE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wall cloud and funnel cloud lowering and raising.  Spotter was looking northwest.