The National Weather Service (NWS) in Rapid City, SD normally launches an upper-air balloon with a radiosonde twice a day. We launch the balloon at 11Z and 23Z. Sounding valid times are 12z and 00z. During Daylight Savings time, the launch time is 500 PM and 500 AM. During Standard time, we launch at 400 AM and 400 PM. For special weather events such as severe weather outbreaks, we can launch the balloon at anytime during the day to sample the atmosphere. Facts about the NWS Upper-Air program are available.
A short video (117 seconds) of an Upper-Air Launch at the NWS Rapid City, SD office:
An NWS Meteorologist prepares the radiosonde for launch.
There is much more to sampling the atmosphere than the brief video and pictures can convey. If you are interested in additional information, please visit the Upper-Air Observations Program web site.