Algol - we used to try and get a ground return on the far side of the storm to see if it was a hole or heavy rain and then tilt up to get an idea how hight the tops were. It was far from foolproof with the small antennas on a piston twin, sometimes you just had to keep away from all of it or heavy rain where you were would blind you to what was coming. I suspect that is still true - heavy enough precip where you are right now won't let you see very well if even worse is in front of you.