I'd have to say its even weak for that, particularly as a 9th level spell. Given that firestorm is 2 levels lower, covers a massive area (2 10x10 cubes per level), deals a crapton more damage, and its effects occur the round its cast. If you have the drop on the enemy, its a much better choice.
Storm takes a full round to cast, doesnt do anything until the 2nd round, you have to maintain concentration, and the supposedly useful obscuring effect doesnt even begin until the 5th round in. The spell's area isnt even THAT big. 360' radius. Your average chain shirt wearing pud will be safely out before the hail starts, and definately out before the rain really kicks in, so the vision limit wont even come into play in many situations. If I'm still standing in the area by round 4 or 5, I failed my save vs. idiocy. The useless d6 acid rain damage isnt good for anything except killing a bunch of commoners or squirrels (maybe) and destroying plant life. How druidic. The spell just blows on so many levels (pun intended). If I'm a 17th level druid, a bunch of 1st level warriors arent particularly going to scare me, and even if they did, there are much more effective tools to dispatch them (and lower level to boot) that dont leave me out of casting for several rounds.