If you are preparing for your first meteorology interview there are some extra things you can be ready for. Most importantly, make sure you are yourself and stay calm and breathe.
My first interview over the phone was with 5 other people and I don't remember anything about it because I was so nervous and I was speaking so fast.
Also, make sure you are on the ball about the weather. Study up on the basics. They are not going to ask you specifics about the math part, unless you are trying to get a job in a math oriented job. They will ask general questions at first and then depending on the job, will get more specific.
I remember I applied to work as a marine forecaster, having no experience in marine and none as a forecaster. I however, had friends that worked for the company and the tipped me off to the types of questions. I made it through a phone interview, two in person interviews and part of a video conference interview. It ended up that the last person I saw didn't like me from the get go, nothing about the questions I was answering.
Make sure you don't go off topic. I got cornered when I went off about a company I would start. So they grilled me business questions, which I wasn't prepared for. I didn't get the job because of those questions.
Dress appropriately for the first in person interview.
Most companies that I dealt with will do phone interviews first before narrowing down the field.
If you are trying to get into the National Weather Service, no matter what any employee of the NWS tells you, you might have better luck playing the lottery.