Anatomy of a very short weather balloon flight over MSP

Twice a day, meteorologists at the Twin Cities and other National Weather Service offices launch weather balloons into the sky.

The balloons carry an instrument package called a radiosonde several miles up into the atmosphere. The radiosonde beams back real-time data on atmospheric parameters like temperature, wind speed and direction, humidity and pressure.

The 6 a.m. launch

Thursday’s 6 a.m. Twin Cities NWS weather balloon launch rose nearly straight up into the atmosphere. Light winds in the lowest mile caused the balloon to rise fairly close to the launch point.

As the balloon gained altitude, stronger but still relatively light westerly winds gently pushed the balloon eastward along Interstate 494 in the southern Twin Cities.

Bloomington balloon burst

The balloon continued to gain altitude over Eden Prairie. By the time it reached Bloomington, it was more than 20 miles above ground level — 108,675 feet above the ground to be precise.

Then it burst.

The parachute on the radiosonde slowed carried the unit gently back to earth. The instrument package began to descend as it drifted over Richfield, the Minneapolis-St. Paul International Airport, Mendota Heights and West St. Paul.

Finally, the parachute guided the instrument package to a landing in Woodbury in the eastern Twin Cities.

Here’s the map of the flight path from Thursday morning’s launch.

An unusually short flight Thursday

Weather balloons launched front the Twin Cities NWS office in Chanhassen, Minn., typically travel 80 to 200 miles. But Thursday’s morning flight was unusually short.

The light wind profile above the Twin Cities produced a flight of only about 30 miles. The NWS Twin Cities tweeted Thursday about the unusually short flight.

Successful data collection

So, what did data the balloon launch gather? This is a little inside weather baseball geeky, but take a look at the sounding below. The left-hand image shows the temperature and dew-point profile with height through the atmosphere.

You can see the wind direction and velocity barbs on the right-hand side of that image at different levels above ground. The right-hand side shows the balloon’s corkscrew path as it rises.

Not always that easy

Thursday’s launch occurred under nearly ideal conditions given the light surface wind. That’s not always the case. Check out this launch under extreme conditions during the April blizzard in 2018.

Neither rain nor snow — nor raging blizzard.