Weather notwithstanding, what kind of traffic does JFK see on a Sunday morning? I have a flight coming up just after the new year, I-D:

ICN-JFK, arriving at 10am (T1)
JFK-ATL, leaving at 1:25pm (probably T4)

I'll have one checked bag, no GE (using Mobile Passport), and I'll be flying J and F (so SP). The first and last time I stopped through JFK I didn't have to change terminals (D-I), so I'm not quite sure what to expect in terms of immigration/customs/transfer times.