Storm Events Database

Event Details

Event Thunderstorm Wind
Magnitude 50 kts.
State IOWA
County/Area GRUNDY
WFO DMX
Begin Date 07/07/2008 17:39:00 CST-6
Begin Range 1
Begin Azimuth S
Begin Location GRUNDY CENTER
Begin Lat/Lon 42.36/-92.77
End Date 07/07/2008 17:39:00 CST-6
Deaths Direct/Indirect 0/0 (fatality details below, when available...)
Injuries Direct/Indirect 0/0
Property Damage 2.00K
Crop Damage 0.00K
Episode Narrative A warm front lifted northeast across Iowa during the day on the 7th as a cold front approached from the northwest. The cold front reached northwest Iowa by the early morning hours of the 8th, however a shortwave lifted northeast across the state during the afternoon and evening of the 7th. The airmass became very unstable by the mid and late afternoon hours as temperatures warmed to the upper 80s to mid 90s and dewpoint temperatures warmed to the upper 60s to mid 70s. CAPE values rose to between 4000 and 6500 J/kg by late afternoon, and lifted indices fell to between -7 and -10 C. The environment was moderately sheared with 25 to 35 kts of shear available. The downdraft CAPE was quite high, and was between 800 and 1300 J/kg. A decent amount of CAPE was available, 300 to 500 J/kg, in the -10 to -30 C. layer of the atmosphere, however the freezing level was very high. Freezing levels ranged from 14,500 feet over northern Iowa to 16,000 feet over the south. With the high freezing level, there was a very deep warm cloud layer with precipitable water values in the 1.6 to 1.8 inch range. The threat for tornadoes with this system was minimal with LCL values around 1500 meters at the beginning of the event, and 2500 meters by early evening. Thunderstorms developed over north central into west central Iowa by the mid afternoon. Very heavy rain fell in north central Iowa where the storms intersected the warm front. Upwards of 4 inches fell in a 2 hour period, however no flooding was reported. As the event unfolded it became a high wind event. The downdraft CAPE was able to be realized with numerous gusts in the 60 to 70 MPH range. There were numerous reports of tree branches broken and several whole trees toppled. Winds of 70 MPH hit the Waterloo-Cedar Falls area. Tree and power line damage was extensive in the area. High winds in Boone County overturned a semi-tractor trailer. No injuries were reported however. Heavy rainfall became a problem, especially after sunset when the line of thunderstorms became stationary over southern Iowa. The heavy rain over the northern part of the state, such as the 2.44 inches that fell in Clarksville in Butler County, did not cause much in the way of flooding. Overnight, a large area of thunderstorms remained over the same areas of south central Iowa. Numerous reports of rain in the 4 to 6 inch range were received in the area with the heaviest rain occurring in the Appanoose and Davis County areas. The schoolnet site in Bloomfield reported 7.68 inches of rain, while the Centerville Schoolnet site reported 7.58 inches. A measured rainfall of 6.9 inches was received from southwest of the Bloomfield area for one of the heavier non-automated totals. Centerville received 6.13 inches from overnight rains as reported by the Cooperative Observer. Appanoose County had received heavy rainfall the day before, as did many of the surrounding areas. The heavy rainfall caused water to flow over may roads and even over a few state highways. Iowa Highway 5 was closed north of Marysville by high water for example. Water also covered U.S. Highway 34 near Albia.
Event Narrative Four to five inch diameter tree limbs down in Grundy Center.


All events for this episode:

Location County/Zone St. Date Time T.Z. Type Mag Dth Inj PrD CrD
Totals: 0 0 575.00K 5.00K
DEER CREEK WORTH CO. IA 07/07/2008 12:55 CST-6 Thunderstorm Wind 52 kts. EG 0 0 3.00K 0.00K
MANLY WORTH CO. IA 07/07/2008 13:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 0.00K
GRAFTON WORTH CO. IA 07/07/2008 13:33 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
CLARKSVILLE BUTLER CO. IA 07/07/2008 15:20 CST-6 Heavy Rain 0 0 0.00K 0.00K
CHURDAN GREENE CO. IA 07/07/2008 15:43 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
LANYON WEBSTER CO. IA 07/07/2008 16:00 CST-6 Thunderstorm Wind 50 kts. EG 0 0 1.00K 0.00K
BOXHOLM BOONE CO. IA 07/07/2008 16:06 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
PILOT MOUND BOONE CO. IA 07/07/2008 16:15 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 0.00K
BRADFORD FRANKLIN CO. IA 07/07/2008 16:33 CST-6 Thunderstorm Wind 56 kts. MG 0 0 2.00K 0.00K
PLAINFIELD BREMER CO. IA 07/07/2008 16:42 CST-6 Thunderstorm Wind 52 kts. EG 0 0 3.00K 0.00K
WAVERLY BREMER CO. IA 07/07/2008 16:44 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
CLARKSVILLE BUTLER CO. IA 07/07/2008 16:50 CST-6 Thunderstorm Wind 57 kts. EG 0 0 10.00K 0.00K
CLARKSVILLE BUTLER CO. IA 07/07/2008 17:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
SHELL ROCK BUTLER CO. IA 07/07/2008 17:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 15.00K 0.00K
WAVERLY BREMER CO. IA 07/07/2008 17:10 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 5.00K
FAULKNER FRANKLIN CO. IA 07/07/2008 17:20 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
GRUNDY CENTER GRUNDY CO. IA 07/07/2008 17:39 CST-6 Thunderstorm Wind 50 kts. EG 0 0 2.00K 0.00K
(ALO)WATERLOO MUNI A BLACK HAWK CO. IA 07/07/2008 18:00 CST-6 Thunderstorm Wind 59 kts. MG 0 0 5.00K 0.00K
(ALO)WATERLOO MUNI A BLACK HAWK CO. IA 07/07/2008 18:01 CST-6 Thunderstorm Wind 61 kts. MG 0 0 10.00K 0.00K
CEDAR FALLS BLACK HAWK CO. IA 07/07/2008 18:03 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
WATERLOO BLACK HAWK CO. IA 07/07/2008 18:05 CST-6 Thunderstorm Wind 57 kts. EG 0 0 20.00K 0.00K
CEDAR FALLS BLACK HAWK CO. IA 07/07/2008 18:12 CST-6 Thunderstorm Wind 57 kts. EG 0 0 25.00K 0.00K
TOLEDO TAMA CO. IA 07/07/2008 18:35 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
ATLANTIC CASS CO. IA 07/07/2008 20:30 CST-6 Thunderstorm Wind 61 kts. EG 0 0 20.00K 0.00K
BLOOMFIELD DAVIS CO. IA 07/07/2008 23:00 CST-6 Heavy Rain 0 0 0.00K 0.00K
CENTERVILLE APPANOOSE CO. IA 07/07/2008 23:00 CST-6 Heavy Rain 0 0 0.00K 0.00K
CENTERVILLE APPANOOSE CO. IA 07/07/2008 23:35 CST-6 Flash Flood 0 0 25.00K 0.00K
SHARON APPANOOSE CO. IA 07/08/2008 00:00 CST-6 Flash Flood 0 0 25.00K 0.00K
ALBIA MONROE CO. IA 07/08/2008 00:00 CST-6 Flash Flood 0 0 10.00K 0.00K
MELROSE MONROE CO. IA 07/08/2008 00:20 CST-6 Flash Flood 0 0 30.00K 0.00K
INDIANOLA WARREN CO. IA 07/08/2008 00:30 CST-6 Flash Flood 0 0 20.00K 0.00K
ATTICA MARION CO. IA 07/08/2008 00:40 CST-6 Flash Flood 0 0 25.00K 0.00K
NEWBERN MARION CO. IA 07/08/2008 01:00 CST-6 Flash Flood 0 0 25.00K 0.00K
MELCHER MARION CO. IA 07/08/2008 01:00 CST-6 Flash Flood 0 0 25.00K 0.00K
AVERY MONROE CO. IA 07/08/2008 01:00 CST-6 Flash Flood 0 0 25.00K 0.00K
BLOOMFIELD DAVIS CO. IA 07/08/2008 02:00 CST-6 Flash Flood 0 0 75.00K 0.00K
SELECTION MONROE CO. IA 07/08/2008 02:00 CST-6 Flash Flood 0 0 50.00K 0.00K
STEUBEN DAVIS CO. IA 07/08/2008 02:20 CST-6 Flash Flood 0 0 25.00K 0.00K
MARYSVILLE MARION CO. IA 07/08/2008 04:30 CST-6 Flash Flood 0 0 50.00K 0.00K
Totals: 0 0 575.00K 5.00K