Past IEM Features tagged: july

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Setting Records in July

08 Jul 2012 11:03 AM
The forgettable week of blistering hot weather for Iowa has mostly come to an end this Sunday. The high temperature in Des Moines hit 100+ degrees for four straight days, but only on Saturday did it tie a previously set record. The featured chart presents the dates and years of daily high temperature records being set or tied. Of note, is the lack of events in July as shown by the highlighted area. In fact, it has been since 1955 that a record was either tied or set in July for Des Moines! The plot overall shows a lack of new records in the summer months. A common explanation for this is that our increased agricultural activity has increased dew points during the summer months through increased plant transpiration. Heating this moisture rich air takes more energy and acts to suppress high temperatures in the mid afternoon. Or others may say that the dust bowl era (1930s) rewrote our summertime records to levels that will be very difficult to exceed without another organized large scale drought event.

Voting:
Good: 109
Bad: 20

Tags:   jul12   july  

July Dew Points

04 Aug 2009 06:14 AM
This past July will probably be the coldest on record once all of the data is collected. The featured plot displays the average dew point for Des Moines for the past Julys since 1973. The lack of humidity helps to allow temperatures to cool off during the night time. August has started off muggy and warm, which is a welcome change of pace for now.

Voting:
Good: 34
Bad: 3

Tags:   jul09   july  


Bucking the trend

31 Jul 2007 06:48 AM
The featured graph is of average July dew points and rainfall (color scale) for Des Moines since 1973. The preliminary total for 2007 is shown with a box around the data point. It is interesting to see how much lower dew points have been this year as compared with the past 10 years. These past 10 years have helped to push the overall dew point trend to +7 °F per 100 years (R2=0.14). Some of the increase is often speculated to be from increased agricultural activity and plant transpiration.

Voting:
Good: 11
Bad: 14

Tags:   july