I was wondering the same since I have an IAD-JFK round trip flight on Saturday and since I am flying back and forth the same day and there is bad weather forecast for that day so I am now wondering whether I am better off taking the flight that leaves early morning versus mid-morning. My ticket is alway an award with money paid for the Even More Space/More Speed premium. I don't fly JetBlue often and last time I flew when there was the threat of a winter storm they cancelled everything whereas Delta kept flying and luckily it was a very odd situation where I happened to also have a return flight on Delta so I just took the refund on JetBlue.