Since setting record high temperatures on Thanksgiving, our weather has been on the windy side with wind gusts measured above 30 mph each day since somewhere in the state. The featured chart presents the climatology of having one or more hours of wind observations at or above 30 mph for each day of the year. The annual signal is clear with these events more limited in the summer and peaking during the transition seasons of spring and fall. There are some localized peaks due to peaks in thunderstorms and strong winter storms.

Voting:
Good = 14
Bad = 2

Tags:   wind  

The wind speed and direction can be broken into two components. These are a south to north (v wind) and west to east (u wind) component. [Those of you that failed geometry may wish to vote bad now]. The featured graph presents the daily averaged u and v wind speed component. This chart shows a clear annual cycle. Outside of the summer months, the jet stream is often nearby and tends to help promote dominant westerly winds. The v winds show us the dominant air temperature advection regimes with northerly (negative v values) during the winter time and warm southerly (positive v) in the summer time. September is shown as a transition period with westerlies increasing and southerlies decreasing.

Voting:
Good = 43
Bad = 6

Tags:   wind   climate  

Sustained wind speeds on Monday were some of the strongest we have seen since early May as shown by the featured image. The black line represents climatology and nicely shows the yearly minimum in winds during the early part of August. Wind speeds will increase as surface temperature gradients become stronger during the spring and fall seasons. Thunderstorms are back visiting the state this morning with more expected into Thursday.

Voting:
Good = 22
Bad = 7

Tags:   2010   wind  

Continuing in the series of climate features, today's plot is of the hourly frequency of an observed 10+ mph wind speed by month based on archived data from Des Moines. Those of us that live in Central and Northwest Iowa notice the many wind farms that are being built. Obviously, these turbines need reliable wind speeds to generate power. This plot indicates that outside of the afternoon hours in the spring and fall, having 10+ mph winds is roughly a 50% or lower chance on a daily basis.

Voting:
Good = 17
Bad = 5

Tags:   climate   wind  

The featured plot continues the series of hourly climatology plots. This plot is of average hourly wind speeds by hour and by month. The windiest time of year appears to be 4 PM in April and the least in the early morning in August. This plot nicely shows two maximums in the spring and fall. These are a result of the season transition periods as warm and cold air fights over Iowa! Large temperature gradients result in stronger winds.

Voting:
Good = 18
Bad = 14

Tags:   climate   wind