what to do about relocating to fl if my14 yr old daughters dad wont let her

We are moving to Florida in 6 weeks and my 14 yr old daughter's dad doesn't want her to leave.I have a custody order and he has visitation but does not follow it.He sees her once in a while and does not help with appts or meetings etc.She has lived with me her whole life and has lived with her step dad for over 6 yrs.She also lives with her 2 sisters,1 brother and step bother and sister which she is very close to.The reasons for us relocating are I have fibromyalgia and the cold weather in pa has me in alot of pain,we also have better jobs set up there and have some friends and family there.Also my daughter has been in alot of trouble in school and poor grades and the school won't help her to get an iep that she needs.We also live in a bad area.I would like to move to florida and get a lawyer once I get down there because I have someone renting my house in pa.So can I do that without a big problem?