Why weather balloons? A moment of science

Storm Team 2
Balloons aren’t just for birthday parties! The ones that meteorologists use are a bit bigger than the ones you get at the store.

Weather balloons are an essential tool for meteorologists as it allows us to capture and record a vertical slice of upper atmosphere. This is the only way we can get this data so twice a day, every day, weather balloons are launched at National Weather Service offices throughout the United States, including our local office in North Charleston. 

Emily McGraw from the NWS was nice enough to let me tag along for a balloon launch- walking me through the process.

First things first, inflating the balloon, made from a biodegradable latex, with either helium or hydrogen. After some time- the balloon is completely inflated to around 6 feet in diameter.

“The whole inflation process takes around 10-15 minutes,” McGraw said.

The balloon provides the lift, but meteorologists care more about what comes along for the ride: an instrument called a radiosonde.

“On the radiosonde…there’s a temperature sensor, humidity sensor, we have pressure, and there’s GPS to derive the winds. So we’re getting that data every second all the way from the surface to over 100,000 feet.”

Emily McGraw, NWS Charleston

This data is visualized in a diagram called a Skew-T. Studying this is crucial in severe weather as it provides answers to how the day might shape up. This data is also ingested into weather models, which in turn creates a better forecast.

Back to the balloon- after ascending for nearly 90 minutes, expanding to nearly 20 feet, it bursts. 

“This parachute will bring it safely back down to Earth with the radiosonde attached to it,” McGraw said.

These radiosondes are expendable and are often lost with only 20% found and recovered, but if you are lucky enough to find one- “there’s a mailing envelope already attached on the radiosonde, so you can pull that out, it already has the postage on it, and you can ship it back so we may recycle and reuse it.”

If you’d like to see a balloon launch, be sure to contact the National Weather Service Office to schedule a visit. 

Storm Team 2 Meteorologist David Dickson

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