A strong storm system developed over the southern Rockies during the early morning hours of the 17th.  A strong frontal boundary extended from the low, northeast across Iowa.  A 50 kt low level jet developed during the predawn hours.  The jet transported significant moisture over the top of the frontal boundary.  Precipitable water values increased to between 1.1 and 1.3 inches over southern Iowa by sunrise.  The atmosphere was strongly sheared with 40 to 50 kts of effective shear present.  The freezing level was quite low, in the 10,000 to 11,000 foot range.  CAPE values increased through the night with MUCAPE in the 1000 to 2000 J/lg range.  CAPE in the -10 to -30 C layer of the atmosphere was between 300 and 500 J/kg.  Downdraft CAPE was less than 500 J/kg.  Thunderstorms developed rapidly during the predawn hours around the frontal boundary.  Many of the storms produced pea size hail with enough hail to cover the ground.  Several storms produced nickel to quarter size hail around sunrise over south central Iowa.  The severe weather decreased during the day as the event turned into a heavy rain event, though isolated storms became severe.  One storm produced high winds, causing some roof damage, and quarter size hail in Ringgold County late in the afternoon.  High winds also occurred during the evening in the Ottumwa area.  Flash flooding occurred in several counties, including Ringgold, Monroe, and Wapello Counties.  Heavy rainfall of 3 to 6 inches fell over parts of the southeast third of the Des Moines CWA.  There was one unofficial report of 7 inches north of Kellerton in Ringgold County, with a 7.3 inch amount in Appanoose County.  The heavy rainfall lead to flooding in many areas.  Several southeastern Iowa counties received a State Declaration by Governor Branstad.  Mahaska was the only one in the Des Moines CWA.

Flood in MARION, IOWA
From 18-APR-13 03:46:00 to 19-APR-13 02:00:00 (CST-6)
Location: BUSSEY
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Highway G71 was closed due to high water over the road from the Cedar Creek near Bussey.

Hail in RINGGOLD, IOWA
From 17-APR-13 17:20:00 to 17-APR-13 17:20:00 (CST-6)
Location: BEACONSFIELD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in WAPELLO, IOWA
From 17-APR-13 19:54:00 to 17-APR-13 19:54:00 (CST-6)
Location: OTTUMWA
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in WAYNE, IOWA
From 17-APR-13 06:33:00 to 17-APR-13 06:33:00 (CST-6)
Location: PROMISE CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Rain in UNION, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: LORIMOR
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.69 inches in the past 24 hours.

Heavy Rain in MAHASKA, IOWA
From 18-APR-13 04:00:00 to 18-APR-13 04:00:00 (CST-6)
Location: OSKALOOSA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Storm total rainfall of 4.25 inches.

Heavy Rain in MARION, IOWA
From 18-APR-13 18:40:00 to 18-APR-13 18:40:00 (CST-6)
Location: DONNELLY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total rainfall 6.20 inches.

Heavy Rain in TAMA, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: TRAER MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Rainfall of 3.04 inches in the past 24 hours.

Hail in APPANOOSE, IOWA
From 17-APR-13 06:44:00 to 17-APR-13 06:44:00 (CST-6)
Location: CENTERVILLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash Flood in RINGGOLD, IOWA
From 17-APR-13 13:21:00 to 17-APR-13 17:30:00 (CST-6)
Location: BEACONSFIELD
Flood cause: Heavy Rain
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Water over County Road P64 and also 210th Street north of Highway 2 with roads impassible.

Heavy Rain in POLK, IOWA
From 18-APR-13 15:00:00 to 18-APR-13 15:00:00 (CST-6)
Location: WINDSOR HGTS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Storm total rainfall 3.22 inches.

Heavy Rain in MARION, IOWA
From 18-APR-13 05:25:00 to 18-APR-13 05:25:00 (CST-6)
Location: KNOXVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total rainfall 5.70 inches.

Heavy Rain in CLARKE, IOWA
From 18-APR-13 05:00:00 to 18-APR-13 05:00:00 (CST-6)
Location: MURRAY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 4.44 inches in the past 24 hours.

Flash Flood in MONROE, IOWA
From 17-APR-13 17:00:00 to 18-APR-13 01:00:00 (CST-6)
Location: AVERY
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Public

Water from creek covering several miles of old Highway 34.

Flash Flood in WAPELLO, IOWA
From 17-APR-13 20:15:00 to 18-APR-13 01:00:00 (CST-6)
Location: OTTUMWA
Flood cause: Heavy Rain
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Ottumwa Police reported several roads and intersections in the city as impassible to cars.

Heavy Rain in POLK, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: RIDER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 2.74 inches in the past 24 hours.

Hail in APPANOOSE, IOWA
From 17-APR-13 06:50:00 to 17-APR-13 06:50:00 (CST-6)
Location: FORBUSH
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail fell from Centerville to 6 miles north of Centerville.

Heavy Rain in APPANOOSE, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: NUMA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Rainfall of 7.30 inches in the past 24 hours.

Heavy Rain in RINGGOLD, IOWA
From 17-APR-13 17:17:00 to 17-APR-13 17:17:00 (CST-6)
Location: MT AYR
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Rainfall of 5.5 inches.

Heavy Rain in STORY, IOWA
From 17-APR-13 19:03:00 to 17-APR-13 19:03:00 (CST-6)
Location: STORY CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Rainfall of 3.50 inches.

Flood in MARION, IOWA
From 18-APR-13 02:10:00 to 19-APR-13 02:00:00 (CST-6)
Location: HAMILTON
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Cedar Creek out of its banks covering Highway 5 in the 2300 block.

Flood in CLARKE, IOWA
From 18-APR-13 05:00:00 to 19-APR-13 02:00:00 (CST-6)
Location: MURRAY
Flood cause: Heavy Rain
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Severe road erosion and washouts noted on some gravel roads.

Heavy Rain in POWESHIEK, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: GRINNELL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 3.20 inches in the past 24 hours.

Heavy Rain in POWESHIEK, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: GRINNELL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.86 inches in the past 24 hours.

Heavy Rain in WARREN, IOWA
From 18-APR-13 05:30:00 to 18-APR-13 05:30:00 (CST-6)
Location: CHURCHVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Rainfall of 4.55 inches in the past 24 hours.

Flood in MARION, IOWA
From 18-APR-13 02:10:00 to 19-APR-13 02:00:00 (CST-6)
Location: PERSHING
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Water over Highway 5 due to the English Creek overflowing its banks.

Heavy Rain in APPANOOSE, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: FORBUSH
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 6.73 inches in the past 24 hours.

Hail in TAYLOR, IOWA
From 17-APR-13 04:16:00 to 17-APR-13 04:16:00 (CST-6)
Location: BEDFORD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Heavy Rain in LUCAS, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: LUCAS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 5.26 inches in the past 24 hours.

Heavy Rain in JASPER, IOWA
From 17-APR-13 19:30:00 to 17-APR-13 19:30:00 (CST-6)
Location: NEWTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 2.55 inches.

Heavy Rain in DAVIS, IOWA
From 17-APR-13 13:52:00 to 17-APR-13 13:52:00 (CST-6)
Location: DRAKESVILLE
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Rainfall from 0300 CST of 3.80 inches.  Creeks in Drakesville area out of their banks.

Heavy Rain in CASS, IOWA
From 18-APR-13 05:00:00 to 18-APR-13 05:00:00 (CST-6)
Location: ATLANTIC
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Rainfall of 1.37 inches.

Heavy Rain in CLARKE, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: OSCEOLA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.86 inches in the past 24 hours.

Heavy Rain in WAYNE, IOWA
From 18-APR-13 05:52:00 to 18-APR-13 05:52:00 (CST-6)
Location: PROMISE CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 5.90 inches.

Heavy Rain in TAYLOR, IOWA
From 17-APR-13 12:30:00 to 17-APR-13 12:30:00 (CST-6)
Location: BEDFORD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall total 3.2 inches.

Heavy Rain in MARION, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: HARVEY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 5.25 inches in the past 24 hours.

Heavy Rain in JASPER, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: KELLOGG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 5.00 inches in the past 24 hours.

Heavy Rain in POLK, IOWA
From 18-APR-13 05:45:00 to 18-APR-13 05:45:00 (CST-6)
Location: BONDURANT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.14 inches in the past 24 hours.

Heavy Rain in BOONE, IOWA
From 17-APR-13 20:00:00 to 17-APR-13 20:00:00 (CST-6)
Location: MADRID
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall total 1.94 inches.

Heavy Rain in POLK, IOWA
From 18-APR-13 08:57:00 to 18-APR-13 08:57:00 (CST-6)
Location: CLOVER HILLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Rainfall of 2.99 inches in the past 24 hours.

Heavy Rain in POWESHIEK, IOWA
From 18-APR-13 05:55:00 to 18-APR-13 05:55:00 (CST-6)
Location: BROOKLYN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.32 inches in the past 24 hours.

Heavy Rain in BUTLER, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: PARKERSBURG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 1.64 inches in the past 24 hours.

Heavy Rain in TAYLOR, IOWA
From 17-APR-13 19:00:00 to 17-APR-13 19:00:00 (CST-6)
Location: BEDFORD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total through 1900 CST of 4.50 inches.

Heavy Rain in WEBSTER, IOWA
From 18-APR-13 05:59:00 to 18-APR-13 05:59:00 (CST-6)
Location: HARCOURT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 1.65 inches in past 24 hours.

Heavy Rain in TAYLOR, IOWA
From 18-APR-13 04:34:00 to 18-APR-13 04:34:00 (CST-6)
Location: BLOCKTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 3.8 inches in the past 24 hours.

Heavy Rain in DALLAS, IOWA
From 18-APR-13 06:30:00 to 18-APR-13 06:30:00 (CST-6)
Location: ADEL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Rainfall of 2.60 inches in the past 24 hours.

Heavy Rain in DALLAS, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: HADDEN HILL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 3.18 inches in the past 24 hours.

Thunderstorm Wind in RINGGOLD, IOWA
From 17-APR-13 17:20:00 to 17-APR-13 17:20:00 (CST-6)
Location: BEACONSFIELD
Magnitude: 61.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Emergency Manager

One inch diameter hail along with damage to house roofs and vehicles.

Thunderstorm Wind in WAPELLO, IOWA
From 17-APR-13 19:48:00 to 17-APR-13 19:48:00 (CST-6)
Location: OTTUMWA
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds of 58 MPH with heavy rain and very low visibility.

Heavy Rain in BREMER, IOWA
From 18-APR-13 06:00:00 to 18-APR-13 06:00:00 (CST-6)
Location: TRIPOLI
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Rainfall of 1.38 inches in the past 24 hours.

Hail in TAYLOR, IOWA
From 17-APR-13 03:30:00 to 17-APR-13 03:34:00 (CST-6)
Location: BLOCKTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Pea to nickel size hail lasted four minutes and covered the ground.