Weather balloons: What goes up must come down

We spend a lot of time talking about what it's doing outside: "It's 85 degrees" or "the dew point is 63 degrees" or "the wind is from the southeast at 7 mph," and so on.

Because we make these observations near the ground (and usually at airports – but that's a different blog post!), we call them surface observations. However, we all know the atmosphere doesn't just exist here close to the ground, and what happens aloft can and does affect the weather here on the ground.

That's why the National Weather Service sends up balloons from a few dozen sites across the country twice a day, in coordination with other weather forecasting agencies around the world. These balloons have small instrument packages attached to them that record temperatures, dew points and pressures as they rise. These data are used by meteorologists and computer models to assess the current state of the third dimension of the atmosphere and aid in forecasting future weather.