A cold front moved into northwest Iowa during the day on the 19th.  The front reached southeast Iowa after midnight.  The atmosphere was unstable ahead of the front with temperatures warming into the mid 80s to around 90, and surface dewpoint readings in the upper 60s to low 70s.  CAPE increased to over 2000 J/kg.  Downdraft CAPE was in excess of 1000 J/kg.  The freezing level was quite high, around 15,000 feet.  Available CAPE in the -10 to -30 C layer of the atmosphere was in the 500 to 800 J/kg range.  Precipitable water was around 1.8 inches.  Adequate shear was available with the effective shear in the 35 to 45 kt range.  A line of thunderstorms developed ahead of the cold front.  The storms became severe by the mid afternoon hours.  The severe period lasted for about 2 1/2 hours in the Des Moines CWA with the most of the severe weather in a band extending from south of Waterloo, through Des Moines, into the southwest corner of the state.  The predominant mode of severe weather was in the form of high winds.  Numerous reports of high winds were received with wind speeds of 60 to 80 MPH.  In the Des Moines metropolitan area, 40,000 customers were reportedly out of power at the peak of the storm.  After 12 hours, nearly one quarter of those still remained without power.  Tree and power line damage was widespread along the line.  Scattered roof damage was reported in the Des Moines metropolitan area as well.  A semi truck was blown over on Highway 169 north of Tingley in Ringgold County.  Spotty hail was reported, mainly in Dallas, Polk, and Marion Counties.  The largest hail was in Marion County with a report of golf ball size hail in Pleasantville.

Hail in STORY, IOWA
From 19-SEP-13 15:07:00 to 19-SEP-13 15:07:00 (CST-6)
Location: ROLAND
Magnitude: 0.75 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:25:00 to 19-SEP-13 14:25:00 (CST-6)
Location: ADEL
Magnitude: 65.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Damage to a garage.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:45:00 to 19-SEP-13 14:45:00 (CST-6)
Location: CLIVE
Magnitude: 69.00 EG
Property damage: 150.00K
Crop damage: 50.00K
Reported by: NWS Employee

Power lines down for about a mile long stretch west of Urbandale.

Hail in MARION, IOWA
From 19-SEP-13 15:41:00 to 19-SEP-13 15:41:00 (CST-6)
Location: PLEASANTVILLE
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:50:00 to 19-SEP-13 14:50:00 (CST-6)
Location: HADDEN HILL
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A six foot section of a privacy fence was blown over.

Hail in MARION, IOWA
From 19-SEP-13 15:50:00 to 19-SEP-13 15:50:00 (CST-6)
Location: PLEASANTVILLE
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:36:00 to 19-SEP-13 14:36:00 (CST-6)
Location: HADDEN HILL
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A 4 inch diameter tree was down with damage to a deck.  Gutters...soffit...and shingles blown off shed.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:53:00 to 19-SEP-13 14:53:00 (CST-6)
Location: DES MOINES
Magnitude: 56.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 65 MPH.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:30:00 to 19-SEP-13 14:30:00 (CST-6)
Location: REDFIELD
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six to 8 inch diameter limbs blown down.  A 12 inch diameter tree was also down.

Thunderstorm Wind in TAMA, IOWA
From 19-SEP-13 16:43:00 to 19-SEP-13 16:43:00 (CST-6)
Location: CHELSEA
Magnitude: 54.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 60 to 65 MPH.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:40:00 to 19-SEP-13 14:40:00 (CST-6)
Location: SHULER MINE
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Numerous 16 inch diameter trees down and a garage door blown out.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:40:00 to 19-SEP-13 14:40:00 (CST-6)
Location: HADDEN HILL
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 60 MPH.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:50:00 to 19-SEP-13 14:50:00 (CST-6)
Location: URBANDALE
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 60 MPH.

Hail in DALLAS, IOWA
From 19-SEP-13 14:33:00 to 19-SEP-13 14:33:00 (CST-6)
Location: ORTONVILLE
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: CARNEY
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Winds estimated at 70 MPH.

Hail in DALLAS, IOWA
From 19-SEP-13 14:39:00 to 19-SEP-13 14:39:00 (CST-6)
Location: ADEL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:55:00 to 19-SEP-13 14:55:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 61.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 70 MPH in Windsor Heights.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:11:00 to 19-SEP-13 14:11:00 (CST-6)
Location: REDFIELD
Magnitude: 58.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Very large tree downed across the road. Power lines down as well.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:03:00 to 19-SEP-13 15:03:00 (CST-6)
Location: ORALABOR
Magnitude: 52.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 60 MPH.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: FT DES MOINES
Magnitude: 58.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six to eight inch diameter tree snapped.

Hail in POLK, IOWA
From 19-SEP-13 14:53:00 to 19-SEP-13 14:53:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:11:00 to 19-SEP-13 15:11:00 (CST-6)
Location: ALTOONA
Magnitude: 61.00 MG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in JASPER, IOWA
From 19-SEP-13 15:39:00 to 19-SEP-13 15:39:00 (CST-6)
Location: BAXTER
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in MAHASKA, IOWA
From 19-SEP-13 16:35:00 to 19-SEP-13 16:35:00 (CST-6)
Location: OSKALOOSA MUNI ARPT
Magnitude: 53.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:45:00 to 19-SEP-13 14:45:00 (CST-6)
Location: GRIMES
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Windows blown out of home. Mutiple 30 ft tall pine trees downed and damaged chain link fence. Some wind driven small hail too.

Thunderstorm Wind in ADAIR, IOWA
From 19-SEP-13 14:13:00 to 19-SEP-13 14:13:00 (CST-6)
Location: ADAIR
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Twelve inch branches broken.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:35:00 to 19-SEP-13 14:35:00 (CST-6)
Location: ADEL
Magnitude: 61.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Two 9 inch tree limbs down.  Virtually every street has some tree damage.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:32:00 to 19-SEP-13 14:32:00 (CST-6)
Location: ADEL
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Trees reported down onto Highway 169 and 15th Street in Adel.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six to 8 inch diameter branches down near Ankeny Blvd. and NE 9th St.  Nine inches of water on the road.

Thunderstorm Wind in MARION, IOWA
From 19-SEP-13 15:54:00 to 19-SEP-13 15:54:00 (CST-6)
Location: LAKE RED ROCK
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Measured at the Lake Red Rock bridge.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:47:00 to 19-SEP-13 14:47:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Tree down blocking 55th street south of Hickman Rd.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:10:00 to 19-SEP-13 14:10:00 (CST-6)
Location: KENNEDY
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 75.00K
Reported by: Amateur Radio

Significant crop damage and a 12 inch limb down.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: ANKENY
Magnitude: 65.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Shingles blown off roofs of several houses.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:45:00 to 19-SEP-13 14:45:00 (CST-6)
Location: DODGE FLD ARPT
Magnitude: 56.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: NWS Employee

Six to eight inch diameter trees snapped.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:10:00 to 19-SEP-13 15:10:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Up to 18 inch diameter limbs and branches down around central Ankeny.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:02:00 to 19-SEP-13 15:02:00 (CST-6)
Location: LOVINGTON
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Twelve inch diameter pine tree snapped in half near Beaver and Amick.

Thunderstorm Wind in MARION, IOWA
From 19-SEP-13 16:15:00 to 19-SEP-13 16:15:00 (CST-6)
Location: ATTICA
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Power line down across the 1800 block of Highway G76 near Attica.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:41:00 to 19-SEP-13 14:41:00 (CST-6)
Location: URBANDALE
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Many tree branches down and a few power lines down.

Thunderstorm Wind in TAMA, IOWA
From 19-SEP-13 16:34:00 to 19-SEP-13 16:34:00 (CST-6)
Location: CHELSEA
Magnitude: 54.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Five inch branches down around town.  Winds estimated over 60 MPH.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six inch diameter branch snapped.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: BONDURANT
Magnitude: 65.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Shingles blown off roofs of several houses with 12 to 18 inch diameter tree snapped in half.  Many 4 to 8 inch branches blown down.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:03:00 to 19-SEP-13 15:03:00 (CST-6)
Location: RIDER
Magnitude: 69.00 EG
Property damage: 75.00K
Crop damage: 50.00K
Reported by: Amateur Radio

Six power poles snapped with power lines on the road just west of the intersection of Highway 141 and Highway 44.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:01:00 to 19-SEP-13 15:01:00 (CST-6)
Location: DODGE FLD ARPT
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several large tree branches down around the area. Some 8 to 12 inch trees snapped off at the base.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:04:00 to 19-SEP-13 15:04:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: NWS Employee

Six inch tree branches down on house, reported by of an off duty NWS employee.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:43:00 to 19-SEP-13 14:43:00 (CST-6)
Location: DALLAS CENTER
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Employee

Eight to nine inch trees blown down.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:57:00 to 19-SEP-13 14:57:00 (CST-6)
Location: URBANDALE
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Minor damage to the roof of a business at the corner of Urbandale Ave and Merle Hay Road.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:05:00 to 19-SEP-13 15:05:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Small to large branches down in Ankeny.  Business sign damage along 1st Street with construction material on the road.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:04:00 to 19-SEP-13 15:04:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six to 12 inch diameter trees down near NE 5th and Trilein.

Hail in DALLAS, IOWA
From 19-SEP-13 14:43:00 to 19-SEP-13 14:43:00 (CST-6)
Location: DALLAS CENTER
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:44:00 to 19-SEP-13 14:44:00 (CST-6)
Location: WAUKEE
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Employee

Two foot diameter tree snapped off a few feet above the ground.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: LOVINGTON
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A 16 inch diameter tree branch was down blocking the intersection of Clinton Ave and 38th St.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:49:00 to 19-SEP-13 14:49:00 (CST-6)
Location: WINDSOR HGTS
Magnitude: 60.00 MG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: NWS Employee

Significant tree and power line damage.  Trees down on buildings.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:44:00 to 19-SEP-13 14:44:00 (CST-6)
Location: CLOVER HILLS
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: NWS Employee

Sixty to 70 MPH winds with lots of small to medium branches down.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:55:00 to 19-SEP-13 14:55:00 (CST-6)
Location: URBANDALE
Magnitude: 61.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Two to three inch diameter limb driven through a car windshield near Douglas and 68th St.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:09:00 to 19-SEP-13 15:09:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An 8 inch diameter tree trunk snapped 2 feet off the ground and laying across the fence line of Northwest Elementary School.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: ANKENY
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Six inch diameter tree was snapped.

Thunderstorm Wind in RINGGOLD, IOWA
From 19-SEP-13 15:15:00 to 19-SEP-13 15:15:00 (CST-6)
Location: TINGLEY
Magnitude: 56.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A semi truck was blown over on Highway 169.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:45:00 to 19-SEP-13 14:45:00 (CST-6)
Location: GRIMES
Magnitude: 69.00 EG
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Roof damage reported at South Prairie Elementary School in Grimes.

Thunderstorm Wind in MAHASKA, IOWA
From 19-SEP-13 16:32:00 to 19-SEP-13 16:32:00 (CST-6)
Location: OSKALOOSA
Magnitude: 52.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several 4 to 6 inch diameter trees down throughout Oskaloosa.

Thunderstorm Wind in WARREN, IOWA
From 19-SEP-13 15:40:00 to 19-SEP-13 15:40:00 (CST-6)
Location: HARTFORD
Magnitude: 56.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds estimated at 65 to 70 MPH.

Thunderstorm Wind in MARION, IOWA
From 19-SEP-13 15:46:00 to 19-SEP-13 15:46:00 (CST-6)
Location: DONNELLY
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tree across the road at 80th Ave 1/2 mile south of Highway 92.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 15:00:00 to 19-SEP-13 15:00:00 (CST-6)
Location: NORWOODVILLE
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

An exit sign was blown down on the east Mixmaster.

Thunderstorm Wind in DALLAS, IOWA
From 19-SEP-13 14:30:00 to 19-SEP-13 14:30:00 (CST-6)
Location: DALLAS CENTER
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Power lines down along Quinlin Ave just northwest of Dallas Center.  Pole damaged at the base and laid over in the ditch.

Thunderstorm Wind in POLK, IOWA
From 19-SEP-13 14:55:00 to 19-SEP-13 14:55:00 (CST-6)
Location: URBANDALE
Magnitude: 69.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Partial roof damage to business located at 5900 Douglas Avenue.

Thunderstorm Wind in WAPELLO, IOWA
From 19-SEP-13 17:00:00 to 19-SEP-13 17:00:00 (CST-6)
Location: OTTUMWA
Magnitude: 52.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees and power lines down in town.