Abundant heat and humidity were again present over Iowa on Tuesday and once again, the combination helped to fire late afternoon thunderstorms that brought heavy rainfall to the state. Based on hourly reports, the heat index topped off at 109°F for Des Moines after a pleasant morning with heat index values only in the lower 70s. This combination is the subject of today's featured chart. The chart presents the hourly distribution of heat index reports on coincident days of having at least one such report of at least 105°F. The black dots show the hourly reports for Tuesday and the hourly violin plots show the distribution of values with the red ends representing the range. So having such cool values during the morning hours is certainly within the range of observed values on record. The wide range that shows up during the late afternoon hours is the result of thunderstorm activity that quickly drops the heat index. It is interesting to note that none of that aforementioned activity appears within the 3 PM observation range.

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Tags:   heatindex