Twice a day, every day, your National Weather Service Office in Rapid City, SD launches an upper-air sounding to measure the three dimensional state of the atmosphere. The morning launch on Friday, November 22, 2013 at 12z was exceptionally dry. The precipitable water measured on the morning sounding was 0.03".
This ties the previous record for November set on November 13, 2007. The all-time record low precipitable water for our sounding site was 0.02" set on December 19, 2006. Precipitable water is defined as:
Measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location, usually extending from the surface to 300mb.
Our sounding and comparison from 12z Friday 2013-11-22 (click for full resolution images):
Here is what an upper-air sounding launch looks like at our office: