June is finally in the books! Des Moines had 22 days with measurable precipitation which ties a record set back in 1902. Even with all those rainy days, we ended June on a very dry note with day four of no-rain in progress today. Friday should be dry as well with rain holding off until the holiday weekend. Hurricane Alex looks to impact our weather on Sunday and possibly bring more heavy rainfall.

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Tags:   jun10   june  

The featured chart plots the relationship between the total rainfall during June with maximum temperature observed based on data from Ames. The red lines indicate the average value and the percentages show the frequency of the observations in each quadrant. Having both above average rainfall and maximum temperature is the least common combination, which makes physical sense as typically the warmest temperatures are associated with dry soils, which implies less precipitation. The 2010 value is shown with the red dot.

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Tags:   june  

The featured image is an attempt to show how the wind changes direction when it rains. While there appears to be no obvious signal in this chart, it is interesting to note the clustering of points around south to southeast. Of course, if we are seeing southwest around to northeast winds, rain is probably not in the immediate forecast.

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Tags:   june  

The table presented here provides an interesting comparison of winds, rainfall, and dew points for the past 7 Junes for Ames. The first noticable value is the average 4 PM dew point of only 54 degrees with all other years in the upper 50s and 60s. Certainly not having much rain is involved in our low dew points due to decreased evaporation, but perhaps the most important factor is the lack of southerly winds shown by the very low value of v-component wind. The v wind is simply the component of the wind from the north or south. A larger value of v indicates a stronger southerly wind and thus greater moisture transport from the more humid air masses to our south. You can see the largest v values associated with very humid June months of 2005 and 2002.

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Tags:   june