Likely to ease, I'm a veteran of many late August ISP-MCO and back trips and always found prices low. I find it futile to chase the "opening day" excitement & hype and think WN dangles a few low fares that are quickly sold out. ISP is a different bear too with no real competition.

If you need to lock it down now, you might want to try MCO-LGA. Or take the earlier in the day $212 NS's and switch if the late one becomes competitive. Sometimes buying the ticket to the next stop the plane goes after ISP saves me a ton but unlikely this one is headed out at 9:30p on a Sat night.