Jul 17, 2008
A frontal boundary was located to the northwest of Iowa and remained nearly stationary as a shortwave advanced across the state. The airmass became very unstable with in the 3000 to 4000 J/kg range and lifted indices in the -6 to -9 C. range. The atmosphere was weakly sheared with 20 to 30 kts of shear. A fair amount of downdraft CAPE was available at the onset with values in the 800 to 1000 J/kg range. CAPE in the -10 to -30 C. layer of the atmosphere was somewhat limited, in the 200 to 300
Source: NOAA National Weather Service Storm Events Database (event 103746). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Polk County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.