<p>Physics probably comes the closest. Make sure to get a good background in math (at least up through linear algebra and differential equations), and maybe through a few geology courses and a programming course into the mix. (A friend of mine is a meteorology major overseas. He said he spent his first year taking general courses in math, physics and geology before he got to the more specialized courses in his second year.)</p>
<p>Have you looked at the websites of a few graduate programs in meteorology? They probably specify what sort of background they are looking for. Since meteorology is not a very wide-spread major, they are used to admitting students with other majors.</p>