Jul 18, 2010
A very unstable airmass was in place over Iowa as a cold front approached from the west. High temperatures the previous day were in the upper 80s and 90s for the most part, with 101 at Fairfield. Dewpoint readings were in the 70s east to near 80 over the west. CAPE was in the 4000 to 5000 J/kg range with lifted indices of -8 to -11 C. Downdraft CAPE was quite high, 1200-1400 J/kg. CAPE in the -10 to -30 C layer of the atmosphere was between 300 and 500 J/kg. The atmosphere was quite strong
Source: NOAA National Weather Service Storm Events Database (event 233432). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Marion County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.