IEM Daily Feature
Thursday, 19 November 2020

November Wind

Posted: 19 Nov 2020 05:35 AM

Wednesday was another very windy day. The winds were out of the south helping temperatures to warm nicely above average. It seems we have had more than our fair share of windy days this month, but does the data validate that impression? The featured chart presents the average daily wind speed between 1 and 18 November for Des Moines. Long term wind climatology plots are fraught with caveats and this plot nicely illustrates one of those caveats. The chart clearly shows a regime shift around the year 1960. This isn't natural variability, but rather a change in observation methods and/or IEM coding bugs! It turns out that recording a wind speed is not necessarily straight forward but subject to many variances including the height of the sensor, type of sensor, dynamic response time, averaging method, and sampling period for a sustained wind measurement. Well that got off into the weeds, but assuming that the past few years are directly comparable, indeed this November has seen more wind than the previous few. Ironically, the 2020 value comes up near long term average shown by the plot!

Good = 12
Bad = 1

Tags:   nov