For NWS Forecast Offices that serve Iowa, only Davenport has issued a tornado warning this year. The featured chart presents the period between the first and last tornado warning issued each year by the Des Moines Office. The year 2012 shows up as quite the outlier on this plot with no warnings after the first part of May for the rest of that year. Making it through the end of April with a warning is not uncommon as six years and the past two have done just that since 1986.

Voting:
Good = 35
Bad = 24
Abstain = 11