Tuesday, September 18, 2012

Summer Overview 2012

The summer thunderstorm season is over, and Fall will officially begin in a few days. During the summer our rainfall amounts by month were: June 0.05" (0.34"); July 2.91" (4.13"); August 2.75" (1.17"); and September through the 15th 0.62" (0.38") - Total = 6.33" (6.02"). Values in parentheses are for the airport (TUS). Normal at the airport is 6.08" and the amount here is about in the middle of years I have records for (1999 - 2012). So the summer was neither very wet nor very dry at these two points - although, it has apparently been quite dry over the grasslands of southeast Arizona.

Here at the house there were 9 days with 0.25" or more; 4 days with 0.50" or more; and 1 day with an inch or more (1.57" on July 15th). It appears that 59% of the summer's rain fell on only four days and within a total time period of only about 4 hours. The key events that determine the rainfall character of the entire season tend to hit very quickly.

The above graphic shows GPS measured precipitable water (PW) at the University campus from June 14 through September 17th. There were several dry periods during the summer, most notable were those during August. below is a graphic showing the average daily dewpoint temperature at the NWS observation site at the airport. generally the Td tracks well with the GPS PW - 54F was the old monsoon definition's key value (which corresponds quite well with PW of 30 mm)..

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