Question About Connecting Flights (BUF) to (NAS)

I am supposed to fly from Buffalo (BUF) to Nassau (NAS) via New York (JFK) tomorrow, I am sure as a lot of you know, there is lake effect snow in Buffalo that is causing weather delays. We are supposed to fly tomorrow out of Buffalo however we will probably get another 1 to 3 feet of snow. I was debating getting a rental car from Buffalo and driving to New York to catch the flight out from there. The question is if I don't show up for the Buffalo to New York flight and it is potentially delayed, would it consider me as a no show and forfeit my tickets for the rest of my trip? Or can I show up to New York and board there? The trip was supposed to start on Sunday but the airport was already shut down, leaving me with three less days to vacation as is.