Meteorologists use a lot of high-tech tools: satellite, radar, computer models... but one of the most important is the simple, helium-filled weather balloons.
For two hours, these balloons reach the edges of space, recording weather data as they go, feeding in back to computers and weather stations across the country. Among the data they record are temperature, wind speed and direction and air pressure. All of that can be used to create a more accurate model of the weather and forecasts.
Eventually, they pop, and float back to the ground, thanks to a parachute. GPS info helps the scientists on the ground find them when they return to earth.
In Weather School, Why Meteorologists Fly Weather Balloons
6ABC WEATHER SCHOOL