Is this a Mystery Cult or an Ex Miscellena Tradition? (or none of the above)
Everything mentioned is cool so far. Some other ideas:
Deft Form (Auram)
"Whistle Up the Wind" (See the Ex Miscellena section of HoH:S)
New Target: Cloud Shadow. Can target anything within the shadow of one specific cloud. As always, the caster must be aware of the target. If it's a completely overcast day, the spell is considered unbounded and therefore doesn't work. Same level as... structure?
A lot of the good ideas for abilities have been mentioned. Can I propose some ordeals and sacrifices, assuming this is a Mystery Cult?
Weak Parma: Terram
Deleterious Circumstances: Indoors with no view of the outside
Mandatory Experimenter (that thing where you are required to use Arcane Experimentation whenever you invent something in the lab).
I'm thinking about a Major Hermetic Virtue ala 'Elementalist', where Auram (as the obvious choice) is the focus, but paired with other Forms. Like Elementalist connects Auram, Aquam, Ignem and Terram, this Virtue should instead pair Auram with 3 other forms. These forms should get the small exp gain, whenever exp is spent on Auram, but not the other way around. And any Auram spell with a requisite of any of those other 3 connected Forms, is not increased in magnitude because of that. But which forms? Aquam comes to mind, for either storms at sea, or rains of various other liquids. Terram comes to mind for magic which changes things from a storm into solid objects, or for storms picking up debris. Ignem could be relevant for controlling temperatures of weather phenomena. Animal for creating rains of frogs etc. Many good options, but I think it should be just 3, and those are fixed in the virtue, no variations. This way it's comparable in power to 'Elementalist'.
Great ideas. My player will have lots to choose from.
Do you mean the ability to create auram vis instead of vim vis in a season? Or did you mean perhaps as an ability where the magus can extract auram vis from a storm? If the latter, I was thinking a stress roll against a fairly high TN with a modifier based on the storm.
Good question. I think of a Tradition more like a collection of like-minded individuals. With respect to a weather tradition, I see mages in that tradition working to build out a body of knowledge (spell texts, summae, and tractatus) about weather. I don't view them as creating initiation scripts to confer additional supernatural or hermetic virtues on its members. My view could be wrong, of course.
It is easy enough for me to create some lost bit of magic lore that the character can build a mystery cult around. And I believe that the player is interested in that approach. But, if creating scripts is possible with a tradition, he might be interested in that approach as well.
I like this one.
And thanks for the ordeals and sacrifices. While the player will not be too happy with those, I think they will work quite well with his initiation scripts.
A Weather Master virtue is intriguing, although I admit to not being too keen on the rain of frogs aspect. Perhaps it is the same 3 forms, but the study bonus only applies from Auram to the other three. And being able to ignore requisites for spells for these four forms would only apply for weather related spells. I think this would make it a minor virtue.
From my own "House Trisana" of mainly weather mages ill add an extra option that we always liked alot.
1st, we added a Weather Magic ability, if you handle it otherwise you will need to figure out another mechanic.
The ability to take a natural weather and place it in storage and then release it whenever they wish...
The ability score is the limit on how powerful "weathers" can be stored, representing the magnitude you would get from making a spell to create it but before adding any Range or Duration, for example "Wrath of whirling winds and water" would be magnitude 8, "Clouds of rain and thunder" would be merely magnitude 1.
The ability score squared is the total number of magnitudes, as above, that can be freely stored together with the magi at any one time(have rules somewhere for how to transfer this into items(lesser enchanted items) that anyone can use and that the magi no longer has to "hold" actively themself).
The ability to control "weathers" Ability score times/week(or day if you want more power), during score rds/use, at up to magnitude power as above. How you capture weather patterns and release them where and how you want them.
(google "Trisana" if you want where the idea came from)