For the second day in a row, something has fallen out of the sky and into a West Seattle neighborhood. Tuesday, suspected plane parts in Gatewood; today, a weather balloon in Fauntleroy. Our photo shows its information-gathering component, a radiosonde, hanging from a utility line near tipster Michael‘s house; the blue NOAA logo is clearly visible, as is “HARMLESS WEATHER INSTRUMENT” and some explanatory text. Michael says what was left of the balloon turned up on his neighbor’s roof. We matched the item in the photo to this page on NOAA’s website, which explains that weather balloons are launched daily from 102 sites around the U.S. Here’s part of the backstory:
As the balloon rises through the atmosphere, radiosonde sensors measure and transmit profiles of air pressure, temperature and relative humidity from the Earth’s surface to about 20 miles high in the sky. While in flight, radiosonde sensors also obtain data for wind direction and speed.
Radiosonde data are received by a ground-tracking receiver, which processes it for transmission to weather forecasters and other data users. This information is a primary source of upper-air data for weather prediction models.
NOAA’s website says the balloons rise up to 100,000 feet before popping. This NOAA image shows one about to be launched in Rapid City, South Dakota:
Michael plans to contact NOAA, whose website says only 20 percent of the radiosondes are returned, though each one comes with its own postage-paid bag! (Hard to tell that when the device is hanging off an overhead wire, though.) P.S. Here are the official instructions on what to do if YOU ever find one.