Just been flying in low level wind about 8mp with no gusts and noticed the phantom was maybe not as stable as other times and guessed it was just the wind. I checked my geomagnetic app after the flight and noticed that the KP index today is level 5, which is a weak geomagnetic storm. I know the level goes from 1 to 9 and 6 is a geomagnetic storm. Anybody know what the magic number is that we should not be flying in. The app says level 5 as affects on communication systems with it being a weak storm. Never actually seen the KP index this high to be honest.