Development of low storm clouds in the atmospheric mixing layer over the NPOL and D3R radars on June 12, 2013 at ~12:00 p.m. CDT. Credit: Walt Petersen /NASA . On Wednesday afternoon, June 12, a severe storm outbreak developed and moved across central and eastern Iowa, and then western Illinois, spawning huge thunderstorms and several tornadoes. NASA's Polarimetric (NPOL) precipitation radar, currently deployed in Iowa as part of the Iowa Flood Studies field campaign for the Global Precipitation Measurement mission, rapidly scanned these storms as they moved across the state. NPOL capturing...