A Mesoscale Analysis of the April 13, 2006 Eastern Iowa Severe Weather Outbreak

On the evening of April 13th, 2006, a line of super-cell thunderstorms passed through eastern Iowa spawning large hail and multiple tornadoes. The system moved into Southern Wisconsin and Illinois and produced extreme hail in those regions as well. The convection that started the whole process was very rapid and somewhat unexpected. The day experienced warm temperatures from an incoming warm front and daytime solar heating. Due to this heating, evapo-transpiration occurred over the corn fields of Iowa and created an unstable planetary boundary layer. After a subsidence inversion cap was broken by a passing low-level jet, deep convection was started throughout western Iowa and worked its way eastward. Strong wind shear throughout the troposphere allowed for the production of super-cell thunderstorms in eastern Iowa.