Weather for Kids

Weather balloons come in a variety of sizes or weights, giving better accuracy and control in how high a balloon will rise and how fast it will rise. Balloons can be made of latex or neoprene rubber. The latex balloons tend to be more spherical when inflated and have a faster, more uniform rise rate into the atmosphere. While neoprene balloons are somewhat elongated and their tops tend to flatten when rising, providing a slower, less uniform rise rate. Severe weather and fast-rising balloons are available, and are used for special purposes. Typical lighter-than-air gases are used in weather balloons and may consist of hydrogen, helium, or natural gas.

The National Weather Service launches weather balloons from nearly 100 locations across the United States. A string on the balloon is attached to a small instrument package called a radiosonde. The radiosonde is a little larger than a can of soda, and consists of special sensors that take measurements of humidity, temperature, pressure, wind speed and wind direction. The radiosonde is tracked by a ground-based radar that collects and processes the weather data. In this area of the country, balloon launches are done twice-a-day at National Weather Service Offices located in Spokane, Boise, and Great Falls. The data retrieved from these balloons are used for local weather predictions. It is also sent to a supercomputer in Washington, D.C., where the weather measurements are used as input for computer modeling of our atmosphere.

A weather balloon flight can last in excess of two hours. The balloon can rise over 100,000 feet or nearly 20 miles into the atmosphere, and drift more than 125 miles from its release point. When the balloon has expanded beyond its elastic limit and bursts, a small parachute opens and the instrument package gently floats back to the ground.