Jun 21, 2013
A very unstable airmass was in place over Iowa during the predawn hours of the 21st. The elevated CAPE was in the 2000 to 3000 J/kg range. Downdraft CAPE was quite high at 1400 J/kg. There was 500 to 600 J/kg of CAPE available in the -10 to -30 C layer of the atmosphere. Moisture was transported into the area with a 30 kt jet and precipitable water values increased to about 1.75 inches. The freezing level was quite high at 14,000 feet. The LCL was only 750 meters, however the convection wa
Source: NOAA National Weather Service Storm Events Database (event 447567). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Winnebago County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.