Actually, it's both. Actually read the entry; it says that it can be used as an element for Evocation. This shouldn't be terribly surprising, given that the book says that taking Sponsored Magic is equivalent to taking both of the appropriate the Channeling and Ritual powers.
Sorta. It's
used as an element...but is really more of a thematic statement of available effects. It definitely gives you Channeling...but it's channeling based on a theme, based on kinds of effects not what element you use to grant those effects. This kind of thematic channeling is, per the rules, only available to Sponsored Magic. Normal magic has to be an element (a means of achieving effects) not a theme (a set of types of effect)...which is a big difference in how the two operate, much like the difference between functional/thematic specialties in Thaumaturgy only if the thematic ones were only available via Sponsored Magic.
So, yes, you can Channel with it. It is
used as an Element. But that doesn't make it precisely the same thing.
Now, luckily, Storms/Weather is a perfectly valid element, so the OP doesn't need to worry about any of this, but it's still a valid and important distinction to draw.