How "big" of circumstances?
obviously there is no one standard to measure the size of circumstantial changes...but i can list a couple of things, which if happen, would make me seriously consider appealing a rejection. It' just me tho.
GPA increases from school's 25th percentile to above school's 50th percentile (it's your senior year...how?)
Feb/June LSAT increases by 3 points or more AND at least in the school's 25/75 range
Schools of higher rank accepted you. I seriously don't see how they would give a sh!t.
Receive additional academic honors from college