if she can show that she is going to advance herself and make a better living, the judge will not hold her back. my X filed a restraining order on me not to remove the children from the state of IN to move to FL. i had a huge career opportunity and the judge let the restraining order go and allowed me to move the kids with me.
if you want to try to stop her, file a restraining order from removing the child from the state. most states the custodial parent has to file with the court to move out of state anyways. this will buy you some time to make your defense, show why the child is better to stay where she is (your family, mother's family, schools, sport teams, etc.) and that mom is not going to advance her current situtation for the better...sounds like she is going on a whim to me. from my understanding interns do not make a whole lot.
i am sorry this is happening to you. i don't want to be the downer about it....but it did work out in my case cause i was moving to make more money and improve the financial situtation the children were in. i wanted to tell you why i was able to do it. (plus X was an abuser and had anger issues)
good luck!
-------------------- to my ex - what goes around, comes around. you'll get yours...