Storm Events Database

Event Details

Event Thunderstorm Wind
Magnitude 50 kts.
State IOWA
County/Area GRUNDY
WFO DMX
Begin Date 07/18/2007 17:00:00 CST-6
Begin Range 0
Begin Azimuth N
Begin Location HOLLAND
Begin Lat/Lon 42.4/-92.8
End Date 07/18/2007 17:00:00 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


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
IOWA CENTER STORY CO. IA 07/18/2007 17:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 5.00K
HOLLAND GRUNDY CO. IA 07/18/2007 17:00 CST-6 Thunderstorm Wind 50 kts. EG 0 0 5.00K 0.00K
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
GRUNDY CENTER GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 0.00K
BUCKINGHAM TAMA CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 10.00K
REINBECK GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MORRISON GRUNDY CO. IA 07/18/2007 17:15 CST-6 Thunderstorm Wind 61 kts. EG 0 0 20.00K 5.00K
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