I was hanging out at home listening to an approaching thunderstorm. I went outside to see the light show. I immediately noticed a very bright green light in the south western sky. It was LED bright and steady, it looked as if it may have had a diamond shape. At this point the storm was getting closer and the winds picked up. This object in the sky was obviously having a difficult time maintaining altitude, it was a lot closer to the squall then I was. This sighting lasted approx 25 seconds, enough time for me another witness to talk about what we were seeing. "look at that" "do you see that" "what's it doing" "that's not an airplane" The light was having a difficult time with the storm. It zigged and zagged momentarily and struggled for altitude. At one point the light "yawed" heavily and the green ultra bright LED like light turned to a dull white light, with maybe a hint or red/pink, this lasted less than a second. As the light rotated back so the green light was facing us, it maintained altitude for an instant before it dropped like a rock out view. It fell from about 30 degrees to below the tree line/roof line in less than a second. That was the last we saw of it. I initially thought this was an airplane, but the light only moved up and down with varied zig zag motion. As an aircraft mechanic/pilot I know that a starboard wing has a green NAV light. I would expect the white light on every aircraft's tail to be equally bright, as well as the port side red light. This was not the case, If you need to change one NAV light bulb.. you change all of them. Plus, no pilot in his right mind would purposely fly into an approaching storm of that magnitude.