Storm Events Database

Event Details

Event Thunderstorm Wind
Magnitude 50 kts.
State IOWA
County/Area GRUNDY
WFO DMX
Report Source Law Enforcement
NCDC Data Source CSV
Begin Date 2007-07-18 17:00:00.0 CST-6
Begin Location 0N HOLLAND
Begin Lat/Lon 42.4/-92.8
End Date 2007-07-18 17:00:00.0 CST-6
Deaths Direct/Indirect 0/0 (fatality details below, when available...)
Injuries Direct/Indirect 0/0
Property Damage 5.00K
Crop Damage 0.00K
Episode Narrative Several boundaries were in position across the state with the main boundary being that left from the previous nights convection from northwest into east central Iowa. At the same time, a cold front approached the state from the northwest while low pressure developed over eastern Nebraska. The atmosphere became very unstable by the early afternoon hours with CAPE values in the 3000 to 4500 J/kg range and lifted indices falling to between -7 and -10 C. Shear across the north half of Iowa was in the 30 to 40 kt range. During the afternoon, temperatures rose into the upper 80s to mid 90s, as dew point readings rebounded in to the mid to upper 70s along the boundary. Thunderstorms erupted by mid afternoon with a large area of thunderstorms moving from northwest into parts of north central and eventually in to east central Iowa. The main mode of severe weather was high winds. There was between 900 and 1100 J/kg of DCAPE available with fairly strong winds in the mid levels. Reports of downed trees and power lines were numerous with wind gust reaching 70 MPH or more with some of the stronger storms. There was little in the way of hail reported, though pea to small marble size hail was common. The available cape in the hail layer, -10 to -30 C. layer of the atmosphere, was significant in the 400 to 600 J/kg range, but the freezing level was very high. Typical of mid July, the freezing level was between 14,000 and 15,000 feet, which limited hail production. The storms moved east-southeast at 35 to 45 MPH for the most part with the first round exiting the DMX CWA by early evening. Thunderstorms began to redevelop during the evening. One of the storms produced penny size hail in the Marshalltown area.
Event Narrative


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All events for this episode:

Location County/Zone St. Date Time T.Z. Type Mag Dth Inj PrD CrD
Totals: 0 0 328.00K 228.00K
BANCROFT KOSSUTH CO. IA 07/18/2007 15:00 CST-6 Thunderstorm Wind 57 kts. EG 0 0 15.00K 5.00K
POMEROY CALHOUN CO. IA 07/18/2007 15:22 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MANSON CALHOUN CO. IA 07/18/2007 15:30 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 5.00K
DAKOTA CITY HUMBOLDT CO. IA 07/18/2007 15:31 CST-6 Thunderstorm Wind 61 kts. EG 0 0 15.00K 5.00K
DAKOTA CITY HUMBOLDT CO. IA 07/18/2007 15:32 CST-6 Thunderstorm Wind 61 kts. EG 0 0 15.00K 25.00K
MANSON CALHOUN CO. IA 07/18/2007 15:33 CST-6 Thunderstorm Wind 61 kts. EG 0 0 15.00K 5.00K
FT DODGE WEBSTER CO. IA 07/18/2007 15:45 CST-6 Thunderstorm Wind 52 kts. EG 0 0 15.00K 0.00K
CALLENDER WEBSTER CO. IA 07/18/2007 15:53 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 5.00K
CALLENDER WEBSTER CO. IA 07/18/2007 15:53 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
EAGLE GROVE WRIGHT CO. IA 07/18/2007 16:16 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
WILLIAMS HAMILTON CO. IA 07/18/2007 16:18 CST-6 Thunderstorm Wind 61 kts. EG 0 0 5.00K 5.00K
BLAIRSBURG HAMILTON CO. IA 07/18/2007 16:20 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
RADCLIFFE HARDIN CO. IA 07/18/2007 16:35 CST-6 Thunderstorm Wind 50 kts. EG 0 0 3.00K 0.00K
ELDORA HARDIN CO. IA 07/18/2007 16:39 CST-6 Thunderstorm Wind 52 kts. EG 0 0 10.00K 0.00K
ZEARING STORY CO. IA 07/18/2007 16:47 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 10.00K
WELLSBURG GRUNDY CO. IA 07/18/2007 16:50 CST-6 Thunderstorm Wind 61 kts. EG 0 0 5.00K 10.00K
HOLLAND GRUNDY CO. IA 07/18/2007 17:00 CST-6 Thunderstorm Wind 50 kts. EG 0 0 5.00K 0.00K
IOWA CENTER STORY CO. IA 07/18/2007 17:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 5.00K
STATE CENTER MARSHALL CO. IA 07/18/2007 17:06 CST-6 Thunderstorm Wind 65 kts. EG 0 0 30.00K 50.00K
MARSHALLTOWN MARSHALL CO. IA 07/18/2007 17:07 CST-6 Thunderstorm Wind 52 kts. EG 0 0 10.00K 0.00K
GARWIN TAMA CO. IA 07/18/2007 17:11 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 3.00K
BUCKINGHAM TAMA CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 10.00K
GRUNDY CENTER GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 0.00K
MORRISON GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 61 kts. EG 0 0 20.00K 5.00K
REINBECK GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MARSHALLTOWN MARSHALL CO. IA 07/18/2007 17:18 CST-6 Thunderstorm Wind 52 kts. MG 0 0 3.00K 50.00K
LA PORTE CITY ARPT BLACK HAWK CO. IA 07/18/2007 17:25 CST-6 Thunderstorm Wind 56 kts. EG 0 0 30.00K 10.00K
GRINNELL ARPT POWESHIEK CO. IA 07/18/2007 17:40 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MONTEZUMA POWESHIEK CO. IA 07/18/2007 18:20 CST-6 Thunderstorm Wind 56 kts. MG 0 0 10.00K 5.00K
MARSHALLTOWN MARSHALL CO. IA 07/18/2007 21:05 CST-6 Hail 0.75 in. 0 0 0.00K 10.00K
ODEBOLT SAC CO. IA 07/18/2007 22:05 CST-6 Thunderstorm Wind 52 kts. EG 0 0 10.00K 5.00K
Totals: 0 0 328.00K 228.00K