A weak cold front settled southeast into Iowa during the evening hours.  The airmass ahead of the front was marginally unstable with lifted indices of -4 to -5 and CAPE values in the 2000 to 3000 J/kg range.  Thunderstorms erupted over north central into northeast Iowa initially.  Inflow to the thunderstorms was in the 15 to 30 kt range.  Farther west, inflow was under 10 KTS, which limited thunderstorm development.  Intense thunderstorms formed over Franklin, Butler, and Hardin Counties.   One of the storms produced tornadoes over Franklin and Hardin Counties.  One tornado touched down in rural Franklin County and crossed the border into Hardin County.  A second tornado touched to the west and south of Ackley in Hardin County.  This tornado also touched down in rural areas and caused little damage.  High winds swept through Ackley as the storms moved through.  There were several reports of hail of nickle to ping ball size.  The storms trained over Butler and Hardin Counties.  Rainfall of 2 to 4 inches in a two to three hour period resulted in flash flooding over southwest Butler, northeast Grundy,  and northeast Hardin Counties.  Later in the evening thunderstorms formed along the outflow of the convection in northeast Iowa.  Thunderstorms fired briefly along the boundary and became severe, producing three quarter to one inch diameter hail.

Hail in JASPER, IOWA
From 16-AUG-04 23:02:00 to 16-AUG-04 23:02:00 (CST)
Location: BAXTER
Magnitude: 0.75 
Crop damage: 2K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in HARDIN, IOWA
From 16-AUG-04 20:00:00 to 16-AUG-04 20:00:00 (CST)
Location: ACKLEY
Magnitude: 52 EG
Property damage: 3K
Reported by: EMERGENCY MANAGER

Tornado in HARDIN, IOWA
From 16-AUG-04 18:12:00 to 16-AUG-04 18:12:00 (CST)
Location: ACKLEY
Tornado F-scale: F0
Crop damage: 1K
Reported by: LAW ENFORCEMENT

Tornado moved from Franklin County into northern Hardin County.  It was in open fields.

Tornado in HARDIN, IOWA
From 16-AUG-04 18:16:00 to 16-AUG-04 18:20:00 (CST)
Location: ACKLEY
Tornado F-scale: F1
Property damage: 2K
Crop damage: 2K
Reported by: LAW ENFORCEMENT

Tornado touched down in farm fields and remained in open country.  It caused little damage.

Hail in FRANKLIN, IOWA
From 16-AUG-04 20:28:00 to 16-AUG-04 20:28:00 (CST)
Location: POPEJOY
Magnitude: 0.75 
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in MARSHALL, IOWA
From 16-AUG-04 22:49:00 to 16-AUG-04 22:49:00 (CST)
Location: RHODES
Magnitude: 0.75 
Crop damage: 2K
Reported by: TRAINED SPOTTER

Hail in HARDIN, IOWA
From 16-AUG-04 18:24:00 to 16-AUG-04 18:24:00 (CST)
Location: ACKLEY
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in FRANKLIN, IOWA
From 16-AUG-04 17:57:00 to 16-AUG-04 17:57:00 (CST)
Location: ACKLEY
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Tornado in FRANKLIN, IOWA
From 16-AUG-04 18:10:00 to 16-AUG-04 18:12:00 (CST)
Location: BRADFORD
Tornado F-scale: F0
Property damage: 1K
Crop damage: 1K
Reported by: LAW ENFORCEMENT

Tornado touched down in farm fields southeast of Bradford.  Tornado then crossed the county line into Hardin County.

Hail in MARSHALL, IOWA
From 16-AUG-04 21:44:00 to 16-AUG-04 21:44:00 (CST)
Location: CLEMONS
Magnitude: 1.00 
Property damage: 3K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Flash Flood in HARDIN, IOWA
From 16-AUG-04 20:30:00 to 17-AUG-04 00:45:00 (CST)
Location: NORTHEAST PORTION
Property damage: 10K
Crop damage: 10K
Reported by: EMERGENCY MANAGER

Hail in FRANKLIN, IOWA
From 16-AUG-04 17:14:00 to 16-AUG-04 17:17:00 (CST)
Location: HAMPTON
Magnitude: 1.50 
Property damage: 10K
Crop damage: 5K
Reported by: GENERAL PUBLIC

Hail in FRANKLIN, IOWA
From 16-AUG-04 17:40:00 to 16-AUG-04 17:40:00 (CST)
Location: ACKLEY
Magnitude: 0.88 
Property damage: 1K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Flash Flood in GRUNDY, IOWA
From 16-AUG-04 19:55:00 to 17-AUG-04 00:45:00 (CST)
Location: NORTHWEST PORTION
Property damage: 10K
Crop damage: 10K
Reported by: AMATEUR RADIO

Hail in WRIGHT, IOWA
From 16-AUG-04 20:13:00 to 16-AUG-04 20:13:00 (CST)
Location: DOWS
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in GRUNDY, IOWA
From 16-AUG-04 18:30:00 to 16-AUG-04 18:30:00 (CST)
Location: WELLSBURG
Magnitude: 1.75 
Property damage: 5K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Flash Flood in BUTLER, IOWA
From 16-AUG-04 19:55:00 to 17-AUG-04 00:45:00 (CST)
Location: SOUTHWEST PORTION
Property damage: 10K
Crop damage: 10K
Reported by: AMATEUR RADIO

Hail in FRANKLIN, IOWA
From 16-AUG-04 17:00:00 to 16-AUG-04 17:00:00 (CST)
Location: COULTER
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in FRANKLIN, IOWA
From 16-AUG-04 17:10:00 to 16-AUG-04 17:10:00 (CST)
Location: HAMPTON
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: LAW ENFORCEMENT