New to premier status (i am silver), flying tomorrow to Guatemala city.

How does upgrade work ?

I have checked in.

For my different segments it shows i am first in the waitlist :
YOW-ORD United BusinessŪ: 6 | Booked: 5 | Checked In: 2
ORD-IAH United FirstŪ: 16 | Booked: 14 | Checked In: 2
IAH-GUA United BusinessŪ: 16 | Booked: 12 | Checked In: 0

Do i have any good chance of being upgraded on any of the segments ?

Max