Akasha can fly as well, so Thor staying up in the air isn't really an advantage. Creating a hurricane takes time, time that Thor doesn't have considering these are speed blitzers. Has Thor ever created lightning quickly in the movies? From what I recall, he needed to lift his hammer, power it up, before lightning fell. Granted it only takes a second or two but if it takes him that long to generate lightning, then it's pretty useless against speedsters like these.
Again, I don't see any way for Thor to hit this vamps. His weather manipulation powers are great but slow. On the other hand, we have no quantifiable idea just how strong the vamps (especially Akasha) are or exactly how durable Thor is. They may or may not be able to hurt him... but I'll take that gamble over the sureness of Thor not being able to hit them.
I noticed that this forum is heavily biased for superheroes, and Thor is my favorite superhero... but I realize his weaknesses and against speedsters, there' not much movie Thor can do.