how to?

Physics. I suggest you contact the poster of http://www.gamesas.com/topic/1367489-screaming-npcs-and-repackaging-game-assets/.

Heavy scripting, new textures/meshes as well.

Hi Prometheus, got your message... replying here because others may be interested. My tornado spell (considering turning it into a shout with a 10 minute cooldown like Call Storm, because... damn) works by creating a stack of volumetric fog activators (using the FXSmokeSmokeLgVol.nif model) each with an attached script that translates them to themselves while rotating 180 degrees, then repeats. This, in combination with the CallStormHazard01 hazard and some custom physics make for a pretty convincing tornado. If I understand you correctly, you don't need physics at all, but just the storm, which should simply things immensely and reduce the strain on the scripting system.

Note that using the CallStormHazard and the Fog objects introduces a rather peculiar bug. From certain angles, the fog will be become almost completely transparent while the CallStormHazard is running, making your storm invisible. The only way I've found to fix it is periodically check the player''s position relative to the hazard center and change its Z angle so that it's always offset 90 degrees from the player heading. It's very annoying and causes a "skip" in the cloud animation when it updates, but it's better than an invisible tornado.

Of course, if you have someone who can create you a nice tornado nif, that would be MUCH easier, but since I don't have the time to learn enough about Blender or Maya to create one, this is how I did it.

Examples of my effect:
http://www.youtube.com/watch?v=ehGMpvTuq0Y
http://www.youtube.com/watch?v=YNlbRelbNok
http://www.youtube.com/watch?v=vYhM8_jVZDw

Edit: Forgot to mention that for the base of the tornado I used one of the Dwemer steam billow animations. While it doesn't actually spin, combined with the rotating clouds around it the illusion is pretty convincing.

Wow, and here I thought I was being creative using the healing nif for my tornado, but this is infinitely better. Well done and I hope you get all of the bugs worked out.

Well I first tried to modify the NIF for Blizzard, because it was already spinning and had some cloud effects.... While struggling with that, though, I wondered how feasible this would be, so I tried it... pretty happy with it

The blizzard is something u rez or is a weather effect you summon? couse eventually I don't even need a tornato ... Actually I want to make a whirlpool , a large huge water gorgus with a superstorm all around ... eventually more strong than normal blizzard ...

...wow

Have you released this in a mod yet?

- Hypno

Prometheus: A whirlpool is almost certainly going to require a custom NIF and some heavy duty scripting (if you want to be able to swim in it or anything). If you want a HUGE swirling storm, like, say, one that goes all around your island, that's almost certainly going to be a weather effect, though you can try something like scaling up the Storm Call hazard to a giant size and see how that looks.

Hypno: It's going to be a part of my upcoming mod, Elemental Mastery. It'll also incorporate updated versions of all my current mods, like Summon Meteor, Earth Prison, Ice Wall, etc. Though probably not Actor Magnet

Hi are u interested in releasing ur mod with another in order to give ur new spells a reason d'etre in an important quest and new landmass or u plan to have them out endependant and learnable by a book placed somewhere in skyrim.?

As for the storm a rotating storm all around a ship would be enough do I need to look for exhisting nif or I have to mak. Custom one? Thx for ur answers...

Prometheus: If you just need a storm around a ship, I highly recommend looking at the CallStormHazard01 hazard, maybe in combination with some volumetric fog that blows across the deck.

My current plan is to release Elemental Mastery as a spell pack like Midas, Phenderix and Apocalypse, with short quests in place to unlock the super-spells like Impact, Blizzard, Whirlwind or Divine Wrath... Unfortunately I have very little free time right now to work on modding, so I have no idea when it will be finished. If you'd like me to work on some effects for your mod I can try to help, but again I don't have a lot of free time so I can't guarantee anything :/