The @NWSSPC issued a Mesoscale Convective Discussion (MCD) for SE IA and NW IL. The MCD stated a 80% probability of a watch. A watch ended up not being issued. The unofficial chart is my attempt at verifying probs given a 50% areal overlap w/ watch poly and within 2.5hr of time. pic.twitter.com/LDclTr5KgU

— daryl herzmann (@akrherz) August 13, 2019