Not balloons, but radiosondes.I watched a documentary about the NOAA's Orion and their missions on the Smithsonian Channel a week or two ago. Showed their planning and the inflight activities that are involved in each flight.
Something I learned from it was that the Orion has a tube that allows the crew to drop weather balloons out of and into the hurricane, which provides data based on the current state of the storm and its strength. Pretty interesting!
I forgot the proper terminology, but remember it being a torpedo shaped object that was sent out of the aircraft. I found it fascinating.Not balloons, but radiosondes.