The crew who never bothered to get updated weather through the entire flight
The weather was immaterial. They had fuel for an alternate, so they were prepared for it. I wouldnt have used my alternate fuel though for the approach but they had onwards clearance giving them a false sense of security that they were about to commence the approach thereby burning it in the process. JFK is well known to send you back to the holding pattern in the middle of an arrival sequence or the approach if there is a delay.
No real Mayday declared
It was pretty clear when the F/O said they are low on fuel and requesting priority.
D6