Heavy Rain in Iowa, October 23 to 25, 2021

Southwesterly flow allowed for deep moisture transport from the Gulf coast region and into the Midwest. At the same time a shortwave trough moved across the central plains and into the Midwest. While severe storms were limited by deep saturation and only modest shear, widespread moderate to heavy rain fell across the entire state. Rain began across southern Iowa shortly after midnight on October 24th and quickly expanded across the state through the early morning hours. This rain lasted through the day before tapering off across the state on the morning of October 25th. Widespread rain totals of over 2 inches were common with the heaviest rain falling across southern to eastern Iowa. A few pockets of 3.5 to over 4 inches fell in this region. Thanks to the long duration and antecedent exceedingly dry conditions, there was no flood impact. In fact, even area rivers showed little change as most of the rain soaked into the ground rather than running off.