One of the most important things for this boss is your range to other players. You have to be close enough to everyone else so that you can quickly move to them when a Storm comes. You do not have a lot of time before it will kill you. Some sort of boss mods is very helpful to let you know when a storm can come, and you can start moving closer to the tank.  What has seemed to work is to spread out in a circle around the tank, having everyone within the square in the middle of the platform. If you are more than about 30 yards from any other player, there is a good chance someone will die from the storm. You just have to watch out if someone gets static charged, and move away from them.

He will shoot a big black lightning bolt at the person who he is storming, so it is hard to miss.