The NWS at Charleston, SC conducts rawinsonde observations at least twice a day. Balloons are launched at our office at 7 AM and 7 PM EDT and 6 AM and 6 PM EST. Weather balloons are simultaneously launched at
91 other NWS offices across the U.S. Special weather balloon flights are occasionally launched to observe the latest state of the atmosphere ahead of significant weather or to conduct
research. The special upper air observations are usually launched at 2 PM/AM EDT and 1 PM/AM EST. The NWS has been flying weather balloons since the 1930s. The data collected by these weather balloon flights are critical for weather model performance and forecast accuracy