A powerful low pressure system has brought windy conditions to the state and such strong storms become more common as we transition from fall into the winter season. These systems need strong temperature gradients, which are difficult to come by during most of the summer season. The featured chart presents the hourly wind speed climatology for Des Moines for three periods within October. The increase in speed during the month is apparent as well as the diurnal influence with the highest average wind speeds during the peak heating hours. The mixing of the lower atmosphere during the daylight hours causes higher speed wind aloft to mix to the surface and increase our winds. By about 4 PM, the lower atmosphere starts to stabilize and higher speed air aloft is not as effectively mixed down.

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